2018 MUDDY CREEK NATIONAL | FULL COVERAGE Ryan Sipes has been racing the National circuit since 2004. His best overall result was 3rd in the 250 East Coast Supercross series in 2011. A few years ago, Ryan switched disciplines to the offroad racing world. He hasn’t forgot about his roots as he makes sure to hit a few outdoor Nationals each yearl. He usually rides the 450 class, but this year he wanted to try to qualify on a 125cc machine in the 250 class at the 2018 Muddy Creek National. With the top 36 qualifying straight out of practice, Ryan qualified 25th out of 71 riders. Check out Ryan ripping around of the Husky TC125 two-stroke in practice at the 2018 Muddy Creek National. Maybe he will be able to score some points today! The post RYAN SIPES QUALIFIES ON A 125cc IN MUDDY CREEK | LISTEN TO THE TWO-STROKE SING appeared first on Motocross Action Magazine.
This story is from the January 1999 issue of Motocross Action Magazine. 1999 KTM 125SX TWO-STROKE SPECS Engine: Water-cooled, 124.8cc, two-stroke, reed-valved engine. Bore and stroke: 54.25mm by 54mm. Transmission: Six-speed, wet clutch. Suspension: 13.4-inch WP 50mm conventional forks and 11.8-inch WP shock Wheelbase: 57.56 inches. Claimed weight: 199.8 pounds. Price: $4998. Those are the tech specs, but these are the questions that most riders want the answers to: QUESTION ONE: IS THE ’99 ENGINE FAST? Fast enough to get from point A to point B ahead of the rest of the 125 pack. Last year’s KTM engine mimicked the power of a CR125. For ’99, Honda should have copied the KTM. With the same Honda-ish characteristics as the ’98, KTM’s ’99 125 blows the lid off of a Honda. The engine is dead down low, but it hits with authority in the middle and revs into the ionosphere. QUESTION TWO: IS THE ’99 ENGINE BETTER THAN THE ’98? A little. After such great success with a brand-new engine in ’98, KTM wasn’t about to dump it all and start with something different for 1999. The power characteristics are the same as in 1998–with improvements. Like Yamaha, KTM has designed a good engine. Now all they have to do is a little tinkering (like Yamaha has done since ’96) to make it great. The 1999 KTM 125SX engine got from point A to point B faster than its competition. QUESTION THREE: WHAT DID KTM DO TO THE ’99 ENGINE? Since KTM revamped the 125SX in ’98, there weren’t a lot of engines changes for 1999. However, KTM did make a few: (1) The 125SX gets a newly designed reed block assembly. It features a two-petal reed assembly and horizontal vanes in the intake tract (a la Honda). The new reed should improve throttle response. (2) The hydraulic clutch, which was tested on the 125SX last year, has proved to be completely reliable. (3) To improve shifting, KTM switched to an all-new shift fork design. The 1999 shift fork uses spring loading to reduce drag and lower the friction coefficient. How? Small springs at each end of the shift shaft suspend it to allow each gear to engage without resorting to excess undercut on the dogs. QUESTION FOUR: WHAT DO THE CHANGES MEAN? You can shift with ease, fan the clutch to your heart’s content and feel the engine be more responsive. In 1998 the Hydraulic clutch on the 125 was the test bed for the big bikes. For ’99, it is the standard by which every clutch is measured. Easy pull, no fading and consistency make the hydraulic clutch a work of art. KTM has come a long way in the shifting department, but they still have a little further to go. Despite the ’99 being easier to shift than the 1998, it still isn’t as responsive as a Yamaha or Suzuki. However, it is on par with the KX and light years better than the CR. QUESTION FIVE: DOES THE ’99 REV FARTHER? Why would you want it to? The ’98 KTM revved forever. The 1999 still revs forever. QUESTION SIX: WHAT ABOUT THE JETTING? Way off. For SoCal’s sea level tracks we had to lower the main jet, pilot jet and raise the clip one position to get the KTM to run crisp. This was our best setting: Mainjet: 185 Pilot jet: 45 Needle: NOZH Slide: 6.0 Clip: Groove number 2 Air screw: 2 turns Note: KTM’s are very responsive to jetting changes. If your bike feels sluggish, keep changing the jetting until it barks. The stock jetting of the KTM 125Sx carb was horrible. It took some time to clean the jetting up. QUESTION SEVEN: WHAT ABOUT THE NO-LINK SUSPENSION? Don’t obsess on the lack of a rising-rate linkage. It doesn’t mean much. By positioning the shock within the known framework of a scalene triangle (one in which the sides have different lengths and angles) it is possible for KTM to duplicate the rising rate of any linkage system. The advantages of the no-link, one-sided system are: (1) Less complexity and fewer moving parts. (2) Future rising rate changes can be accomplished by moving the lower shock position (rather than redesigning a complicated linkage). (3) Shock access is excellent. (4) The one-sided shock makes room for a straighter carburetor tract. Two years ago Ohlins developed a special twin-piston damper to use with the no-link system. So why does the KTM have a WP (White Power) shock? Three reasons: (1) KTM owns White Power. (2) Ohlins couldn’t or didn’t want to produce the shock for the price. (3) KTM licensed the technology from Ohlins and had WP build the shock. The KTM shock features two damping pistons (instead of one). One piston is speed sensitive (to the speed of the oil rushing through it). The second piston is position sensitive (to the location of the shock shaft). How does the WP shock know which piston to listen to? A tapered rod runs down through the shock shaft and half way through the shock’s stroke the rod activates both pistons (prior to halfway only the speed-sensitive piston is operational). QUESTION EIGHT: HOW WELL DOES THE NO-LINK WORK? Better than most linkages. Boy, what a difference a year makes. The original No-Link PDS system was flawed from the get-go. Not due to placement, positioning or spring rates, but bad valving. One generation later KTM has sorted out the bugs, redesigned the piston and delivered a No-Link rear suspension system that is better than most of its competitors’ linkage systems. The PDS WP no-link rear suspension always got a bad wrap, but it has its advantages. QUESTION NINE: WHAT WAS OUR BEST SHOCK SETTING? What was our best shock setting? For hardcore racing we recommend this shock set-up: Spring rate: 7.6/11.0 kg/mm Race sag: 95mm Compression: 6 clicks out Rebound: 14 clicks out Notes: Common sense and years of experience tell a rider that turning the compression clicker in (clockwise) will stiffen the compression damping. Not so on a KTM. Turn the clicker out for more compression and in for less. All in all, the ’99 PDS system receives a good rating. It works best with minimal compression damping. QUESTION TEN: HOW GOOD ARE THE NEW FORKS? Gone are the wimpy 45mm Marzocchi conventional forks and in their place are 50mm WP conventional forks. This is a great change. The 1998 Zokes worked well, but suffered from terminal maintenance problems. The Dutch-built WP’s work very well, without the blown seals, warped shims and questionable metallurgy of their Italian counterparts. Is there a downside to the WP swap? Yes. Weight. The 50mm WP forks weigh 7 pounds more than the Marzocchi 45’s. Can that weight be felt? Yes, but since the WP forks work so much better, it is a small price to pay. QUESTION 11: WHAT ARE THE BEST FORK SETTINGS? What was our best fork setting? For hardcore racing we recommend this set-up: Spring rate: 0.40 kg/mm Oil height: 150mm Compression: 11 clicks out Rebound: 10 clicks out Fork leg height: 3mm above triple clamp Notes: There is something to be said about 50mm forks. Because of the 125’s smaller size, flex is slim to none. Out of the crate, KTM is the only company with good spring rates, valving and clicker settings. 1999 was a big year for the KTM 125SX. It made huge improvements to the bike and became competition for the Japanese manufactures. QUESTION 12: HOW DOES IT HANDLE? Like a Japanese bike. If you were expecting the same old line about how KTM’s feel tall and flop through the turns, guess again. The KTM 125 still doesn’t crave tight turns, but it will carve when asked to. European GP testing and a slightly slack head angle keep the KTM stable on the high speed stuff. KTM gets kudos for their aluminum bars and handlebar bend, but they fail miserably in the categories of bar height and placement. The bars feel low–so low that the sensation of going over the bars never goes away. We ditched the stock bars for a set of Honda highs. If that doesn’t work, KTM recommends switching to an Applied KTM top triple clamp that moves the bar clamps up 5mm and forward 10mm. KTM has been fine tuning their easy access air box design for years now. QUESTION 13: WHAT DID WE HATE? The hate list: (1) Color: We like orange. Orange and black is okay (although it smacks of Halloween and Harleys). However, we draw the line at orange, black and silver. Let’s lose one of the three. (2) Fork guards: We kind of hope that WP would make a front number plate/fork guard combo similar to Suzuki’s. (3) Front fender: Earth calling! The worst looking fender in the universe. (4) Rear fender: The gray rear fender turns white in blotches. It gets ugly fast (plus why is it gray in the first place). (5) Gas cap: The gas cap is too small. (6) Radiator wings: The rear corners of the radiator wings hook on your leathers. (7) Side panels: Whoever designed the trapezoid shape of the KTM side number plates never put a number on a bike in his life. No matter what angle you put the numbers on it’s wrong. (8) Turning radius: When turning left, the fork tubes hit the ignition black box. Since there is no black box on the right side, the KTM can turn farther in that direction. Come on guys, move the black box. (9) Air filter: We love the easy access airbox, but on several occasions our Twin-Air filter was pushed off the edge of the cage while pushing the D-shaped cage into the airbox. Always check around the edges for air leaks. In 1999, KTM was one of the only manufactures using aluminum bars. However the bend was much too low. QUESTION 14: WHAT DID WE LIKE? The like list: (1) Clutch: It’s hydraulic. Good thing, because the Honda-style power requires lots of clutch work. This is the clutch of the future. (2) Airbox: It’s cool not to have to remove the seat to get to the filter, but be very careful that the recess cage doesn’t knock it off when putting the air filter in. (3) Handlebars: The bars are aluminum–very cool, but too low. (4) Tires: Bridgestone M77/78 are very good intermediate terrain tires. We like this sneaker combo. (5) Silencer: Very quiet. When you combine the lack of low-end and the absence of sound, it’s eerie. You gas it just to make sure it’s running. (6) Frame guards: KTM and Kawasaki are the only manufacturers to include plastic frame guards to protect the paint on the tubes. (7) Brakes: We have often referred to KTM brakes as “Euro brakes.” What are Euro brakes? Ones that you have to pull on with more effort than “Japanese brakes.” For ’99 the KTM brakes are powerful enough to avoid the Euro nomenclature. The front is powerful and, for a change, the rear isn’t a light switch. (8) Shock preload: Instead of two interlocking preload rings, KTM uses one thick single ring (which clamps to the shock body via an Allen bolt). To adjust the spring preload you loosen the Allen bolt, turn the preload to the correct sag and then tighten the Allen. However, you can’t tighten the Allen if you don’t make a full revolution with the preload ring. QUESTION 15: WHAT DO WE REALLY THINK? Let’s review. Engine: Like a Honda but better. Don’t try and lug the KTM. Once you get in the midrange you will be infatuated, and when you hit the top end you will think it’s true love. This is a good midrange and up engine. Handling: Sitting on the KTM it feels tall. Riding it you think the front is too low. Once you fix the handlebar problem with a new set of bars, you will find a bike that does nothing remarkably good or bad. Suspension: This bike has top-notch suspension. The new 50mm WP Extreme forks handle small and big bumps alike. The rear suspension, although not as silky smooth as the front, handles bumps with a consistent demeanor as long as you don’t get confused and turn the compression adjuster the wrong way. Overall rating: Last year KTM shocked everyone with a 125 that was competitive with the Big Four. This year, the KTM isn’t just competitive, it’s better than most of the big four. Welcome to the party. The post 1999 KTM 125SX TWO-STROKE RACE TEST appeared first on Motocross Action Magazine.
This test is from the 2001 February issue of Motocross Action Magazine. QUESTION ONE: IS THE 2001 SUZUKI RM125 FASTER THAN THE 2000 RM125? If it wasn’t Suzuki would have wasted a lot of money designing an all-new engine. The 2001 is faster than the 2000, but that wouldn’t be too hard to accomplish–the 2000 engine was fun to ride but produced very little horsepower. And by very little we mean about two horses less than the class leader. The 2001 engine is still fun to ride, but now makes horsepower–not as many ponies as the fastest bikes in the class, but darn close. Over the years Suzuki resisted the urge to jump on the Yamaha YZ125 powerband wagon. They stayed their course. What is the RM125‘s niche? Rev over grunt. To make the most of the RM125 powerband you have to be comfortable living at 12,000 rpm. The 2001 RM125 has almost limitless rev. QUESTION TWO: WHAT’S NEW WITH THE RM125 ENGINE? What isn’t? Here’s the short list of changes: (1) The engine cases have been downsized. (2) The water pump is back on the outside of the engine. (3) The cylinder sits at a 17-degree angle instead of last year’s 20-degree angle. This allows for a straighter intake tract. (4) Last year’s Keihin carb has been replaced by a 38mm Mikuni TMX–yes, we said 38mm! (5) The ignition black box is lighter. (6) The shift shaft has been hollowed out. (7) The diameter of the ignition rotor has been decreased by 4mm. (8) Crank mass is redistributed to compensate for the smaller ignition rotor. (9) The exhaust port is wider and reshaped (after being shrunk last year for durability). Suzuki closely examined every part to see if weight could be saved. In the end, the engine lost almost two pounds. The 2001 engine is faster than the 2000, but that wouldn’t be too hard to accomplish–the 2000 engine was fun to ride but produced very little horsepower. QUESTION THREE: WHAT’S THE RM125’S BEST ATTRIBUTE? Midrange hit (combined with a whole lot of rev). There is something to be said for a 125 that hits hard in the middle and then pulls into the upper stratosphere. However, that kind of power puts the onus on the rider to decide how to use it–there are two choices: (1) The most obvious choice is to catch gears in the meat of the midrange and try to ride the wave. It might be the logical option, but in our opinion it’s risky. If you try to ride the RM125 in the midrange, as you would a Honda or Kawasaki, the RM125 will fall flat on its face when you shift to the next gear. (2) The second choice, is actually, the best choice. Rev it to death. Wring its little guts out. Hold it on long and hold it on hard. Once the RM125 engine hits in the midrange, hold the throttle wide open until you can’t take it anymore–then, and only then, shift. QUESTION FOUR: WHY DOES THE RM125 REV SO HIGH? Because they designed it to. KTM, Yamaha and Suzuki have all made conscious decisions to go for high-rpm rev by mounting big carbs (carbs that would normally be OE on a 250). The side effects of super-sizing the carb on a 125 is a loss of low-end (witness the 2001 KTM 125SX and Yamaha YZ125). Big carbs don’t become efficient until the revs are high enough to create sufficient fuel velocity (this doesn’t happen until the dogs start to howl). A lot of factors go into making the big carb work. Suzuki uses a high-rpm ignition curve (with the advance tilted to the top-end) and a small reed cage inlet size (to aid in increasing fuel velocity). The end result is a 125 that rivals the rpm of an Indy Car. The 2001 Suzuki RM125 revs really high due to its big carb. QUESTION FIVE: IS IT THE FASTEST 125 OF 2001? Heavens no. In our opinion Yamaha and KTM still outshine the RM125, but it’s a big improvement over last year’s anemic RM125. QUESTION SIX: HOW GOOD IS THE GEARING? Atrocious. Two years ago Suzuki had 12/50 gearing on the RM125. They switched to 13/49 for 2000. Now, in 2001 and it has 12/49 on it. Forget second gear turns, let alone second gear starts. Save yourself a lot of trouble and gear the RM125 down. We had our best luck with two more teeth on the rear sprocket. If you don’t gear it down–it will fall off the pipe with regularity. Stock gearing on the RM125 is horrible. It needs to be geared down. QUESTION SEVEN: WHAT ABOUT THE JETTING? Jetting the 2001 RM125 takes trial and error (not to mention brass). The hardest part of jetting the RM125 is finding a lean enough pilot jet to clean up the rich bottom end. Here are our best settings: Mainjet: 460 Pilot: 25 (27.5 stock) Needle: 6BGY23-75 Slide: 5.75 Air screw: 1 1/2 turns Clip: 3rd QUESTION EIGHT: WHAT ABOUT THE REAR SUSPENSION? Suzuki’s engineers came to the conclusion that the RM250‘s suspension woes may have been caused by Showa–so they threw Kayabas at it. Surprise! It’s still jacked up. Even more surprising was that Suzuki decided to stick with Showa components on the RM125–and it is pretty good. We won’t say the rear suspension is perfect, but it is more race ready than any RM125 since ’95. It still has a slight tendency to blow through the stroke (only this year it will take a much harder landing or bigger bump). We spent most of last year hating the progressive-rate rear shock spring. Thankfully, Suzuki saw the light and switched to a straight rate 4.8 kg/mm rear spring for 2001. QUESTION NINE: WHAT WAS OUR BEST SHOCK SETTING? You can race the 2001 Suzuki RM125 with the stock rear suspension and not fear for your life. That’s a big improvement. Here’s our best setting: Spring rate: 5.0 kg/mm (4.8 stock) Race sag: 98mm Hi-compression: 1.5 turns out Low-compression: 12 clicks out Rebound: 15 clicks out Notes: Spring choice depends on rider weight and speed. We chose a 5.0, but smaller riders can stick with the stock 4.8 (depending on their speed). QUESTION TEN: WHAT ARE THE BEST FORK SETTINGS? It should be noted that Showa switched their fork diameter from 49mm to 47mm for 2001. The downsizing may not make sense to you, or to the MXA wrecking crew, since Suzuki’s race team runs even larger 50mm tubes, but Suzuki believes that the new lighter frame and steering geometry work better with the smaller diameter fork tubes. For hardcore racing we recommend this set-up: Spring rate: 0.42 kg/mm Oil height: 390cc Compression: 8 clicks out Rebound: 14 clicks out Fork leg height: Level Notes: Slide the Suzuki forks up and down in the triple clamps to alter the handling (down for more stability and up for sharper turning). When working on the forks, please note that Showa doesn’t measure fork oil height in millimeters, but rather in cubic centimeters of fluid. QUESTION 11: HOW DOES IT HANDLE? Better than last year. Suzuki has a rep for building “cornering machines”–a reputation they have worked hard to keep in spite of beaucoup criticism. To keep the RM agile, Suzuki changed the head angle from 27.75 to 26.5 degrees. Very risky! The RM125 has always been twitchy and the head angle change could easily have sent the RM125 into a graveyard spiral. But, it didn’t! The new head angle was combined with totally new frame (one that is more resilient) and the whole package got better. The RM125 is still a carving knife, but now it’s a steady one. If we had to race on a supercross track this is the bike we’d do it on. No other bike feels as good in the air, in tight turns or on hard ground, but there is one caveat: As swift and agile as the RM is on a supercross track, it is busy and loose on an outdoor track. QUESTION 12: WHAT DID WE HATE? The hate list: (1) Bars: Weird bend. (2) Plastic: It may be light, but it came at a price. This is the thinnest and flimsiest plastic we’ve ever seen. (3) Jetting: Fat on the pilot. (4) Clutch: The Suzuki clutch runs on the verge of perpetual slip. This is a marginal clutch at best. (5) Gearing: So bad it’s embarrassing. (6) Graphics: Buy aftermarket graphics before your leave the showroom floor. You’ll need them after the first ride. (7) Reliability: We’d rate Suzuki’s durability last after Honda, Yamaha, KTM and Kawasaki. QUESTION 13: WHAT DID WE LIKE? The like list: (1) Ergos: For years it seemed like RM’s were only designed for small people. Finally, taller riders will feel at home on the 2001 RM125. (2) Front brake: Suzuki has an excellent front brake (if you don’t mind a little squeaking). (3) Shock spring: We’re happy to see Suzuki dump the progressive-rate spring for a straight rate. The rear suspension is much improved. (4) Color: The pale yellow has its detractors, but it stands out. QUESTION 14: WHAT DO WE REALLY THINK? You have to give Suzuki props for going all out in 2001. They spent mega bucks redesigning both the RM250 and RM125. How successful were they? One out of two ain’t bad. Suzuki struck out with the RM250, but with the RM125 Suzuki hit a home run. The post TWO-STROKE TUESDAY | WE TEST THE 2001 SUZUKI RM125 appeared first on Motocross Action Magazine.
Ever wish that Honda would start building two-strokes again? Why wait? Here is a quick primer of how one man built his own. By John Basher Just as with other major things in today’s world, there are opposing views in the dirt bike world. There are die-hard two-stroke loyalists and new-age four-stroke aficionados. A line has been drawn in the sand. As the popular saying goes, “You can’t have your cake and eat it too.” Don’t tell that to Justin Steyn, who has managed to do the unthinkable. The South African has blended the lines by shoehorning a 2001 Honda CR250 two-stroke engine into a 2016 Honda CRF250 four-stroke chassis. It took a judicious amount of money, help from a stranger, lots of research and a little bit of luck. MXA sat down with South African Justin Steyn to have him take us through the steps. WHERE DID YOU COME UP WITH THE IDEA OF PUTTING A 2001 CR250 ENGINE IN A 2016 CRF250? The Honda CR250AF idea popped into my head when my 2011 CRF250 four-stroke was ready to be upgraded. I enjoyed the four-stroke but craved the excitement of a two-stroke again. Believe it or not, the 2016 CRF250 frame I used was the third frame I acquired during the build. I first started with a generation-four 2014 CRF250 frame, but then found a clean 2016 CRF250 came up. I sold the previous 2014 CRF250 engine for three-quarters of what the 2016 bike cost! Building from just a frame up would have been too costly to source all the parts. As with most CR250 builds, the cylinder and head are from a 2001 CR250. That was the last of the good Honda CR250 engines before they went to case-reed induction. Why not a case-reed engine? It suffered from the wah-wahs. TELL US WHY YOU CHOSE THE 2001 HONDA CR250 ENGINE? I read in MXA that the 2001 was the best-performing CR250 two-stroke engine, as it was the last of the cylinder-reed engines before Honda went to the case-reed design with an RC power valve. How I acquired the engine is actually a pretty funny story. I called a guy who advertised a CR250 engine. It turned out that he had a CR250 engine and was looking for a first-generation CR250 frame. We got to chatting. Lo and behold, we had both come across a 1998 CR250 that was for sale. We met up and paid 50/50 on the 1998. I got the engine and he got the rest. I was happy as long as the engine ran. At that stage I sourced a nice 2001 CR250 head and cylinder. I also purchased all of the Wiseco internals that I could. The engine was built with Wiseco internals (crankshaft, piston rod, bearings and piston). There was also a Keihin carb with Intelajet system, Moto Tassinari VForce reeds and a Scalvini pipe. WHY DID YOU CHOOSE A CRF250 FOUR-STROKE CHASSIS INSTEAD OF A STANDARD ALUMINUM CR FRAME? I had owned a second-generation CR250 years ago and loved it. Having said that, the whole project was based on building something pretty trick for the same price (or less) than a new CRF450. I’m an absolute Honda nut and will not ride any other brand. I had to make my own CR250, since Honda discontinued them in 2008. HOW MUCH FABRICATING WAS NEEDED TO PUT THE CR250 ENGINE IN THE FOUR-STROKE CHASSIS? The fabrication wasn’t too complicated. I outsourced the welding and fabrication to a local welder—David from Dreyer Corp. I did some online research of other aluminum frame conversions and learned a lot about them. Basically, the frame’s Y downtube piece needed to be swapped out to allow the head pipe to fit through the frame. The swingarm was spaced using OEM spacers on the CR250 engine, and a new head stay had to be welded in. The exhaust mounts had to be modified, but fitting the carburetor and airbox together was the trickiest bit. On the 2016 CRF250 frame the Y-down tube was rebuilt to allow the pipe to fit through the frame. The swingarm pivot was spaced for the two-stroke cases. The hardest part was lining up the airbox and carb. HOW MUCH DID THE TOTAL BUILD COST? I didn’t keep a record of all the costs, in case my wife found the figures! In all honesty, the total price was just below the price of a new Honda CRF450 four-stroke. WHERE DID YOU SPEND THE MOST MONEY? The engine cost the most, because I really wanted to build a strong powerplant. I ordered all-new Wiseco internals—crankshaft, piston rod, bearings and piston. I also invested in a new 2001 OEM head and cylinder, Keihin carburetor, Moto Tassinari VForce reeds, Intelajet system and a Scalvini pipe. The head, cylinder and carburetor were sent to Dick’s Racing for mods. They taper-bored the carburetor from 36mm to a 39mm, as well as installed the Quad Flow Torque Wing and Intelajet. Most of these mods were decided on after reading about them in MXA. The rolling chassis was a steal. It was a Honda demo that a salesman had dropped off a trailer. The bike had some road rash on the master cylinder, front brake lever, side panel and exhaust. It was minor damage, but it caused the bike to sit on the dealer floor for ages. The dealer eventually sold it to me at cost. After I sold the engine, the rest of the bike cost me about $1000. Despite the minor damage, the bike was a low-hour machine. I could tell by the fact that the brake discs and rims were still like new. LET’S TALK ABOUT THE TRICKY BITS. HOW DID YOU DEAL WITH THE SPACE WHERE THE FUEL PUMP WAS AND INSTALL A FUEL LINE FOR THE CARBURETOR? The pump was easy to remove. I had an aluminum plate fabricated to fit. It bolted right on without issue. There’s an outlet pipe to which the fuel line attaches. Truthfully, that part was rather simple. In front of the gas tank are the air hoses and adjustment dial for the Intelajet carburetor system. It kicks in extra fuel when vacuum pressure in the carb venturi demands it. HOW DID YOU CONFIGURE THE OLD-STYLE TWO-STROKE AIR BOOT? The Moto Speed Shop did the fitment. We used a CR500 airboot and coaxed it into place with the Keihin carb and OEM CRF250 airbox. The reason we used a CR500 airboot is because sourcing the older CR250 airboot is not too easy. They have become scarce. DID YOU OPT FOR A HIGH-COMPRESSION PISTON OR GO OVERBORE? We went with a high-compression Wiseco piston at the stock bore. Dick’s Racing increased the compression by milling the cylinder head. Moto Speed Shop balanced the crank and piston. The bike also has a Vortex X10 ignition. WHAT KIND OF FUEL AND PREMIX ARE YOU RUNNING, AND AT WHAT RATIO? I had some issues with pinging on 95-octane pump gas, so I switched to Avgas. I’m running it at a 40:1 ratio. I live in Johannesburg, South Africa, and it’s 5550 feet above sea level. The finished project combined Honda parts from 2001 all the way up to 2016. DID YOU ACCOMPLISH EVERYTHING YOU WANTED WITH THE BUILD? Yes and no, but for the most part the bike ticks all the boxes. The CR250 chassis has the looks, and the bike has plenty of power. Some think there is too much power! Overall, the bike has the go to match, even if I don’t! The missing item that I would like to get is some Showa A-kit suspension. I’ve tracked some second-hand kits down, but the exchange rate with U.S. dollars makes it a little too much of a sting for now. The crazy thing is, I think the new 2018 Honda CRF250 is a stunner. I might want to start a project on one of those. The post ONE MAN’S JOURNEY TO CR250 TWO-STROKE NIRVANA appeared first on Motocross Action Magazine.
How awesome is this CR125 build? We want it. This is Aleksandr Strizhakov dream bike. He wanted to make a replica of the new aged 2018-19 CRF250 with a CR125 engine. He has been in the works of this build from early 2017. We featured his bike on MXA back in September when it was in the works. It is worth a look to see the start of the build. Another nine months have past and Aleksandr sent us an email about his story and photos of his 2019 Honda CR125 build. Take notes Honda, or Russia is going to build them for you. Take it away Aleksandr: Underneath the CR125’s clothes. “The construction of the bike of my dreams was somewhat delayed, but it has finally come to fruition. I am an engineer and a designer that really loves motocross. I like the handling in the frame of the third generation Honda CR125, and I decided to put it in the hull of Honda’s new design body. It was an excellent and interesting job. I hand built the subframe and transmission and carbon air box. Since I needed a new fuel tank, I decided to make it out of titanium. I applied my method of hydroforming the sides of the tank using a hand grease pump. Next, I worked with metal sheet and after that the entire tank was TIG welded by a friend and the best welder Vladimir. This is the titanium gas tank that can be seen on my bike! I am a perfectionist and decided to build a motorcycle from the best parts in the world, and many parts are made by me. The bike was very light and handling amazing. It has powerfull Motostuff front motor Powerful brakes motostuff rotor well that is controlled be an RE caliper. Of course the engine is inferior to the engines of the KTM and Husky and even Yamaha. But I am 55 years old and the engine suits my riding capability perfect. I also used a hydraulic clutch to help the engine (the bad news is that did honda not make the hydraulic clutch on the 2019 model)! But I can install any two-stroke engine in this frame. Here is a list of details and work: An up close look of the hand-made carbon fiber airbox and subframe. Chassis: 2004 Honda CR125 frame and swingarm. Honda 2017 plastics and seat (I installed the front wing of the 2016 model, which is more suitable for a light 125). D.I.D. LTX rims that I lightened and powder coated the hubs Suspension: 46mm Öhlins front forks that have titanium nitrided lower tubes. Emig modified and polished triple clamps. KYB KXF250 rear shock (shorter than the Honda at 6mm, which lowered the rear of the bike) The 2004 Honda CR125 engine. Engine: 2004 Honda CR125 is that used a Wiseco piston, V-force valve, Pro Circuit pipe and carbon-titanium silencer, Barnett clutch basket and pressure plate and powder coated the right side engine for works factory look. AJP hydraulic clutch master and main cylinder. Brakes: Motostuff 270mm front rotor and Ride Engineering caliper (hand modified and polished for works factory view) Used the stock rear caliper that I vented the body by drilling and used a titanium piston and BBR pedal/ titanium LS footpegs Aleksandr welding his hand-made titanium tank. Hand made: Titanium thickness 0.8mm gas tank. Aluminum subframe. Carbon fiber air box. Full complete titanium bolts.Titanium front/ rear axle and swingarm pivot bolts. Titanium footpegs bracket and more titanium small parts Best regards, Aleksandr Strizhakov. Russia. Sankt-Petersburg The finished product. Aleksandr was finally was able to ride his dream build after more than a year and a half. Motostuff front brake rotor with a custom brake caliper. How trick is the mounting of the CDI box. A close look at some of the customization of the subframe and silencer bracket. Aleksandr Strizhakov and his dream build CR125. Closer look of the caliper. Up close with the hand-made subframe. The post TWO-STROKE TUESDAY | 2019 HONDA CR125 BUILT IN RUSSIA appeared first on Motocross Action Magazine.
THE GEAR: Jersey: FXR Revo, Pants: FXR Revo, Helmet: Scorpion VX-R70, Goggles: EKS Brand GOX, Boots: Alpinestars LE Tech 10. Q: FIRST AND FOREMOST, IS THE 2018 HUSQVARNA TC125 BETTER THAN THE 2017 TC125? A: Yes. The small changes that Husqvarna made to the TC125 for 2018 make it a better all-around race bike; however, if you already own a 2017 TC125 and have spent time and money working on your suspension and jetting, the added cost of stepping up to the new bike would be better spent on new pistons and rings for your old bike. At its core, the 2018 Husqvarna is the 2017 TC125 without the horrible jetting. If, however, you have a 2015 or 2016 TC125, you’ll appreciate the technological leaps that Husky made over the last two years.The 2018 Husqvarna TC125 is only the fourth year that the tiddler has been imported to America. It came into its own in 2017 when it got the WP AER air forks. Q: WHAT IS THE HISTORY OF THE HUSKY TC125 OVER THE LAST FEW MODEL YEARS?A: It would be pointless to go back in time and look at the original Swedish-built, Cagiva-built or BMW-built Husqvarna 125s, so let’s just focus on the period of time when KTM became involved. 2013: The 2013 model year was the last of the BMW-owned, Italian-built, old-school Husqvarna CR125s. The coolest thing that Husqvarna did in 2013 was to include a complete 144cc top-end kit with each CR125 sold. The 2013 CR125 had a narrow, high-rpm powerband that only a highly skilled sugar freak could keep in the sweet spot. Ridden flat out, it was a fun bike to ride, but ridden half-heartedly, it was frustrating. It was, however, a much better bike with the 144cc top-end installed. Back in 2013, a Husqvarna CR125 cost $6299. 2014: Husqvarna, now owned by KTM and moved to Austria, did not import a TC125 two-stroke or FC350 four-stroke to the USA in 2014. That doesn’t mean that the company didn’t make a 2014 Husqvarna TC125—just that it didn’t import it to the USA. KTM had purchased Husqvarna in late 2013 and didn’t have time to come out with a complete fleet of new models for 2014. So, they just gussied up the existing KTMs in white plastic to get the Husky ball rolling. They decided to focus on the TC250 two-stroke and FC250/FC450 four-strokes for U.S. consumers. 2015: It wasn’t until 2015 that Husqvarna brought the first TC125 to American shores. It was a clone of the 2015 KTM 125SX but with white plastic, a molded airbox/subframe and the slipperiest seat cover ever put on a motocross bike. It shared everything else with the KTM 125SX, including the harsh WP 4CS forks, terrific Brembo brakes and strong hydraulic clutch. It was a good bike if you knew a suspension tuner for the 4CS forks and owned a drill for the airbox. 2016 Husqvarna TC125. 2016: This was the year of the big change for the Husky. Every piece of the 2015 engine was re-engineered for 2016. The clutch shaft and crankshaft were moved up for a more compact package. Engine weight was reduced by 4 pounds. It had a new cylinder, piston, head, crankshaft and six-speed transmission. The new frame had 20-percent-greater torsional rigidity and 30-percent less longitudinal stiffness. The head angle was steepened by 0.4mm, and the wheelbase was shortened by 10mm. The triple clamps were rubber-mounted, although they still held WP 4CS forks. The 2016 TC125 was a vastly improved bike. But, the 4CS forks and choked-up airbox were both Debbie Downers. 2017: Husky finally dropped the poorly rated 4CS forks for the all-new WP 48mm AER air forks. It was a massive improvement and saved 3 pounds at the same time. Other changes in 2017 included a 10mm-longer brake pedal, revised rear brake pads, Mikuni TMX 38mm carburetor, bridge-style top bar mounts, ODI lock-on grips and Dunlop MX3S tires. The only downside of the 2017 Husqvarna TC125 was the swap from the proven Keihin carb to the unproven Mikuni. There were jetting issues. The retail price was $6999. The left-side panel can be removed without tools to expose the airbox. The seat is held on with one bolt, and the stock muffler is supported by a molded hanger. Q: WHICH LEADS US UP TO THE 2018 HUSQVARNA CHANGES A: Here is a quick list of the modifications that Husqvarna made to the 2018 TC125 two-stroke. (1) Fuel mixture. Last year the Husky engineers told us to run a lean 60:1 fuel/oil mixture. For 2018 the engineers reversed direction and told us to run a much more common 40:1. The brass ensemble has been changed for 2018 with the same 480 main, richer 35 pilot, leaner air-screw setting and a 6BFY42-75 needle instead of last year’s 6BFY43-73. (2) Fork settings. The 2018 WP AER forks have been updated with a new air seal, air piston and rebound spring on the air leg, along with a new piston on the damping side. For 2018 the compression damping has been firmed up in the mid-stroke. Last year’s AER fork had free-bleed around the compression shim stack, which made the damping too light in the mid-stroke, which created a high-speed flutter in consecutive braking bumps. For 2018 Husqvarna’s engineers addressed this issue; however, what they did to the 2018 forks was not rocket science, and any reputable suspension tuner can duplicate the mods. (3) Clutch. The metal clutch plates have been nitrided, which means they are case-hardened by a heat-treating process that diffuses nitrogen into the surface of a metal. (4) Miscellaneous. The 2018 radiator guards don’t have the shelf that trapped dirt last year, but you can drill out your 2017 shelf or clean your radiator guards between motos to achieve the same thing. A C4 transmission bearing has been installed to increase reliability by virtue of more internal clearance during thermal expansion. For 2018 the shift star is Metal Injection Molded (MIM). In this process, 15-micron metal powder is heated and injected into a mold cavity under high pressure to produce a shift star with closer tolerances than a CNC-machined part. (5) Frame. The frame is exactly the same as in 2017. (6) Shock. The valving has been revised to work with the new fork valving. Q: ARE THE FORK MODS AN IMPROVEMENT ON THE 2018 AER AIR FORKS? A: Yes. The compression damping has been firmed up into the mid-stroke. Last year’s free-bleed around the compression shim stack was the source of considerable flutter in braking bumps and over fast chatter. For 2018 WP put a larger shim (30mm instead of 26mm) against the mid-speed valve to increase low-speed compression by 5 percent and to lessen the high-speed compression by 10 percent. The rebound-damping shim stack remains the same. In a strange move, the fork’s mid-valve, which was constructed from a special ceramic composite material in 2017, was changed back to the previous sintered-steel material. From the earliest prototype version of the WP air fork, the air seal has undergone constant updates. The first version of the AER forks, which were only installed on 2016 European models, had an air seal that could not handle cold temperatures and would leak air pressure from one chamber to the other. WP changed the seal material to a more resilient and less temperature-sensitive compound. Unfortunately, that was not the perfect cure. In 2017, when the AER forks were first introduced in the American market, the lip seal was replaced with a quad-ring seal. The quad-ring solved lots of problems, but because it had four small sealing surfaces instead of one large one, repetitive wear became an issue. For 2018 the WP AER forks switched to a larger air seal to replace the 2017’s quad-ring seal. The new seal has a unique, slightly out-of-square shape that increases surface area for better sealing and longer wear. Husky’s TC125 engine is amazingly compact. They achieved this by stacking the engine shafts vertically. Very trick. Q: WHAT DO YOU NEED TO KNOW ABOUT THE AER AIR FORKS? A: The 2018 air forks are better than last year’s version. Don’t let the demise of Showa SFF-TAC air forks or Kayaba PSF-2 air forks fool you into thinking that air forks can’t be made to work. The WP AER air forks avoided Showa’s and Kayaba’s problem areas by simplifying the air fork concept. You don’t have to have a degree in plasma physics to tune the WP air forks. Unlike Showa and Kayaba, who tried to reinvent the wheel, WP designed its forks so the air pressure in the forks does nothing more than replace the coil springs. On the 2018 TC125 forks, we actually hovered around the recommended 124-psi setting—and never ventured too far away. Slower or lighter riders could go down a few pounds, but for the majority of test riders, we actually upped the air pressure a couple of pounds. This helped hold the forks higher in their stroke, which not only made the forks feel more resilient but balanced out the chassis at the same time. We selected each test rider’s optimum air pressure by placing an O-ring (or zip-tie) on the right fork leg. Then we had them ride a few laps with the stock air pressure. When they came in, we looked at how much travel they were using and raised or lowered the air pressure to get them within 1 inch of full travel. From that point on, we relied on the compression clicker to fine-tune the stroke. We went out on the compression until it stroked through too quickly and then went back in a few clicks. We loved that we could just pull over and adjust the compression by hand. The rebound, however, is on the bottom of the fork and is adjusted by a flat-bladed screwdriver. Q: IS THE 2018 HUSKY TC125 FASTER THAN THE POORLY JETTED 2017 MODEL? A: Yes. Thank goodness. It was a nightmare last year trying to sort out the jetting. This year it is in the ballpark. It’s not perfect, but it’s much closer. We went one size richer on the main jet (490) and Husky went two sizes richer on the pilot (35). We still believe that the Mikuni TMX 38mm carburetor is inferior to the Keihin PWK carburetor, which was less temperamental and ran cleaner throughout the range. Although, when we think back a few years, the Keihin had its teething issues too. Husqvarna did not switch from Keihin to Mikuni for a performance boost. Although Husky, KTM and Keihin have been mum on why the carbs were changed, we assume that it was a production capability issue at Keihin’s factory or a significant price difference between Keihin and Mikuni, or maybe a little of both. Whatever caused Carb-Gate, we miss the no-hassle Keihin. Getting the most out of your WP AER air forks means following a set regimen that takes less than an hour of test times. If you haven’t ridden a new-age 125cc two-stroke, you will be pleasantly surprised. They have much broader powerbands than in the good old days. Plus, the Husky TC125 has a clutch that can take a boatload of abuse without whimpering. The Husky powerplant pumps out 37 horsepower (great for a bike that only weighs 195 pounds). The power-to-weight ratio is incredible. Numerically, there are not a lot of performance items that make the 2018 TC125 better than the 2017 model, but when you aren’t chasing brass, you can get more out of an engine with less worry. On the negative side, the TC125 takes longer to get to the meat of the powerband compared to the KTM 125SX due to the restrictive plastic airbox design. Once in the power pocket, the engine pulls on top like an Audi into a garage wall with granny at the wheel. But, you can get better Husky power by cutting out the right side of the airbox with a box-cutter and drilling a few holes in the left airbox side panel just behind the air filter. Husqvarna specs a 42 N/m shock spring. It is lighter than an FC250 or FC450 spring, but it works great. Q: HOW DOES THE HUSKY TC125 HANDLE? A: Better than any four-stroke you have ever ridden. Without the rotating inertia of a valve-and-cam engine to deal with or the extra tonnage of the complicated four-stroke engine, you can put the TC125 where you want it. And, if you change your mind about where you want it, you can muscle it to a new line in an instant. The fact that the Husqvarna TC125 weighs 33 pounds less than the 2018 Honda CRF250, 31 pounds less than the RM-Z250, 27 pounds less than the YZ250F, 25 pounds less than the Husky FC250 and 23 pounds less than the KTM 250SXF is what accounts for the little two-stroke’s handling prowess. It’s quick, agile, light and flickable. Q: HOW WAS THE STOCK GEARING? A: Given the effects of the plastic airbox on low-to-mid throttle response, the 2018 Husqvarna TC125 could use a bit more bark to get it out of corners. MXA’s faster test riders could use talent to keep the power in the sweet spot, but mortal men elected to swap the stock 50-tooth rear sprocket for a 51-tooth rear sprocket. It helps jump the power up into its effective range sooner. But even more important, it makes third gear more effective. Husqvarna installs an hour meter on every bike at the factory. They don’t stay at 0.2 hours for very long. Q: WHAT DID WE HATE? A: The hate list: (1) Spacers. There are spacers in the seat-bolt hole and right-side panel that fall out when you remove either of these two bolts. Shouldered bolts or tolerance-fit spacers would solve this problem. We used grip glue. This issue will be addressed for 2019 at the factory. (2) Sprocket/spokes. Watch the sprocket bolts. They loosen up constantly. The same holds true for the spokes, especially the one next to the rim lock. (3) Front brake hose. Be very careful when hooking tie-downs onto your handlebars that they don’t crimp the L-bend tube coming out of the front brake’s master cylinder. Always use soft-tie straps. (4) Tiny Torx. Although the left-side panel pops off without any tools, the right-side panel requires a #20 Torx wrench or 6mm socket. Plus, you’ll need a #20 to bleed the forks. To make matters worse, the clutch-side ODI lock-on grip can only be removed with a #15 Torx wrench. (5) Gearing. The best all-around fix for Novices and Vets is to gear it down one tooth. (6) Frame guards. Why paint the frame white if you are going to cover the most visible parts with full-length black frame guards? Q: WHAT DID WE LIKE? A: The like list: (1) Weight. This bike feels as light as it is. (2) Brakes. They are the best in the class. And since these are the same brakes that come on the heavier Husqvarna FC450, they are even more impressive on the 195-pound TC125. (3) Hydraulic clutch. Husqvarna’s self-adjusting clutch is ahead of its time—or are the Japanese brands way behind the times? (4) Airbox. After years of having to wrestle big filters through small holes, the KTM/Husqvarna air-filter design is a blessing. We don’t think changing an air filter could get any simpler. (5) Engine. This small but mighty engine puts out some serious power. If you want better throttle response, you can get it with a drill. (6) Suspension. The WP suspension components are getting better each year. (7) Tires. The TC125 comes with Dunlop Geomax MX3S tires front and rear. Q: WHAT DO WE REALLY THINK ABOUT THE 2018 HUSQVARNA TC125? A: The best thing about riding a 2018 Husky TC125 is blowing by a bunch of guys on $20,000 450cc four-strokes. This test rider weighs 195 pounds. The Husky TC125 weighs 195 pounds. They are in the same weight class. Guess who wins a wrestling match? MXA’S 2018 HUSQVARNA TC125 SETUP SPECS This is how we set up our 2018 Husky TC125 for racing. We offer it as a guide to help you find your own sweet spot. WP AER FORK SETTINGS First, focus on balancing out the bike for your weight by adjusting the air pressure in the forks. If the forks are diving into the corners, go up a few psi. If they tend to be rigid and push on the entrance of corners, drop the psi down a few points. For riders between 155 and 170 pounds, we ran 127 psi. Riders 170 to 200 pounds favored 130 psi. Once the pressure was set, all the riders went softer on the compression. The forks have good bottoming resistance, so going softer for a plusher ride was not an issue. For hardcore racing, we recommend this fork setup for the 2018 Husqvarna TC125 (stock settings in parentheses): Air pressure: 127 psi (124 psi) Compression: 24 clicks out (12 clicks out) Rebound: 15 clicks out (12 clicks out) Fork-leg height: First line Notes: Don’t worry about checking the WP AER fork’s air pressure every time you hit the track. Do, however, bleed both of the air screws on the top of the forks. WP SHOCK SETTINGS The rear shock has a stiffer initial feel compared to last year, making the setting in the ballpark for just about all of our test riders. After we set the sag at 105mm, most riders didn’t change a thing. For hardcore racing, we recommend this shock setup for the 2018 Husky TC125 (stock specs are in parentheses): Spring rate: 42 N/m Race sag: 105mm Hi-compression: 2 turns out Lo-compression: 15 turns out Rebound: 15 turns out Notes: The stock shock settings are in the ballpark. The majority of MXA test riders made no adjustments other than sag adjustments for their weight. This shock may not be up to Kayaba YZ125 shock standards yet, but it is closing the gap each year. MIKUNI TMX 38MM JETTING SPEC Here’s what we ran in our 38mm TMX (stock settings in parentheses). Main jet: 490 (480) Pilot: 35 Needle: 6BFY42-75 Clip: 3rd position from top Air screw: 2 turns out Notes: The TMX carb can be temperamental at times, but in most cases, an air-screw adjustment is the best place to start ironing it out. MXA FIRST RIDE VIDEO: 2018 HUSQVARNA TC125 The post MXA MOTOCROSS RACE TEST: 2018 HUSQVARNA TC125 TWO-STROKE appeared first on Motocross Action Magazine.
RV On A YZ125 The post Ryan Villopoto’s 125 Two-Stroke Weekend appeared first on Transworld Motocross.
An all-new two-stroke engine from Yamaha? Yes! The post Yamaha’s 2019 Two-Stroke Lineup Includes A New Engine appeared first on Transworld Motocross.