Cycle News - Archive Issues - 2000's

Straker-modified Yamaha IT-R250 Our Strok....modIfIed YamaINI (Leftl Pemaps the single most important modification Is trashing the stock CY carburetor for a 36mm Mikuni "pumper" carbo n-R250 pnoject bib _ ...safonned Into qutte a capable GIf-.cI bike wItII just a few NIaItweIy minor boIt-on c"-.... A FEW CHANGES DO WONDERS FOR THE TT-R friendly, as well, but listed above are some of the standouts that really take the hassle out of going trail riding. Still, there's no way around it - the TT-R could certainly benefit from a bit more oomph from its modest, aircooled 250cc motor and stiffer springs for the suspension, even for my 165 pounds. So it was time to make some phone calls. My main objectives with our Cycle News TT-R test bike's motor was to give it just a little bit more boost overall and clean up throttle response, so when Stroker's Larry Roeseler immediately offered to tear into the TT-R's motor and stroke the thing to a 300cc trench-digger, I hesitated. Not that I wouldn't like to do that someday, but I was thinking of something a little less extreme for this particular project. Keeping reliability in mind, I wanted simple, not to mention inexpensive. Roeseler said, "Sure, we can do that, too!" Roeseler kept his word by keepiryg the mods simple, yet effective. To improve throttle response, Roeseler simply replaced the restrictive 34mm CY -type carburetor for a more throttle-sensitive, freer-flowing 36mm "pumper" Mikuni carburetor, the single most expensive modification of this project. The carb sells for $375 and comes complete with all the necessary hardware (cables, jets, etc.) for easy bolt-on installation. (I'll tell STORY AND PHOTOS BY KIT PALMER like serious, hard-core off-road riding as much as the next guy, but there are times when I enjoy nothing more than to unwind and take it easy for a while by heading for the hills or desert for a weekend of no-pressure, non-serious and purely for-fun trail riding. Sometimes, you just want to go riding without worrying about if there's a hidden checkpoint around the next corner. So, when the mood strikes me, I'll park my favorite "fullrace" off-road bike for something a little... no, a lot more mellow, like the Yamaha TT-R250. Going trail riding on the TT-R250 doesn't get much simpler: Since it's a thumper, you don't have to worry about mixing gas - you can top 'er off directly from the pump with the bike still in your truck. Since it's a smallbore thumper, you can pretty much ride all day on that one tank of gas. Since it has an electric starter, there's no kicking, and since the TT-R's lowcompression engine isn't churning out crank-twisting horsepower, you don't have to worry much about breaking down when you're 50 miles away from camp. Since the suspension isn't tuned for the Jack Pine National Enduro, the ride is Cadillaclike plush. There are many other little tidbits that make the TT-R250 very 48 OCTOBER 31, 2001 • cue I e n e _ so you right now, the carb kit is worth every penny.) To perk up the motor a little more, he swapped the stock exhaust system for U.S. Forestry-approved SX1 Stroker Exhaust System, including the header pipe. According to Stroker, the new header for this bike is actually more important than the new tail section because the TT-R's stock header is so restrictive. The tail piece sells for $235 and the header for $140, but if you don't want to go the whole nine yards for both, Stroker recommends that you should at least go with the new header first and then think about purchasing the tail piece later on. That was about it for the motor mods. Dealing with the suspension was even easier. To give the TT-R's suspension a little more girth, Stroker beefed up the suspension by installing stiffer springs from Progressive Suspension, including Roeseler Signature fork springs. The internals were left alone. That was about it for performanceenhancing mods, but we weren't done yet. Perhaps the most important modification I wanted to make to the TTR250 was yet to come, and it had nothing to do with bettering the bike's on-trail performance, but, more importantly, it had to do with improving the TT-R's on-trail versatility. In other words, I wanted to make the TT-R street-legal. That way, you can wheelie right past those annoying "street-licensed vehicles only" signs you sometimes see out in the deserts and trails and go exploring, and then, if you want, ride into town for lunch and gas (and fuel for your bike, too). To accomplish this relatively easy goal, Stroker installed a super-sano Baja Designs dual-sport kit on our ITR, and our project was officially finished. Nice and simple. My biggest concem, once I got our project bike back from Stroker, was noise: Would the new exhaust system be too loud? To my relief, it was not. Yes, it was slightly louder than stock, but definitely not excessively louder. On the trail, our Stroker-modified TT-R250 felt just as I had hoped. The new carburetor did, in fact, give the bike better throttle response and a crisper feel, while the new exhaust pipe gave it a bit more snap across the [j)iiJ~I![j)fX]D©§ f1DfSTl SX 1 Stroker Exhaust System $370 Mikuni Carburetor $375 Baja Designs Dual Sport Kit $370 Progressive Suspension Roeseler Signature Fork Springs $84.95 Progressive Suspension Shock Spring $89 .95 Seat Foam $50 Seat Cover $80

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