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DTT April BOTM Winner

DTT April BOTM Winner
By Dime City Cycles April 17, 2017 1 comment

In 1978 while in High School Jim Platek bought a brand new Yamaha XS500, a road bike with an 8-valve double overhead cam 4-stroke twin cylinder. This started a 37 year "bond" with the bike. “It was my commuter, tourer, road racer, and dragracer. I finally decided that it was time to change things up, and I parted out all but the frame, switchgear, gas tank, and mirrors.”

A buddy sold Jim a 1989 YZ250 roller chassis which supplied the front forks, triple trees, wheels, brakes, swingarm, and a seat base. “I was looking for the right engine for a long time. I wasn't exactly sure what the right engine was at that point, but I knew it had to be a 2-stroke! NOT a motocross engine, as I had already done a CR500 for a drag bike in another XS500 chassis. I watched Craigslist, eBay, and I posted want-ads everywhere. Finally I found a destroyed Yamaha Blaster YFS200 quad.” A stock Blaster engine is a 196cc, aircooled, counter balanced, 6-speed single cylinder.

Jim did a complete top to bottom rebuild with a Hot Rods 4mm stroker crank, Wiseco forged 1mm over piston and Wiseco forged clutch basket, V-Force 4 CF reeds, a 36mm Mikuni TM Flatslide carb, he made his own billet intake manifold, and did enough cylinder porting to cause Carpal Tunnel. “My good friend Bob machined the squish head and cylinder bore, and supplied the RD350 expansion chamber. It displaces 217cc and gets well over 45 mpg! I modified the swingarm to utilize one shock on the right hand side, eliminating the entire linkage and the giant centrally located monoshock. I thought what the heck, let's try this, and it works quite well while being a bit different.”

The tires are Shinko SR241 DOT trials tires, 21" up front and 19" rear. “They are soft and sticky, handle great, and yet wear amazingly well.” The fenders are Acerbis YZ250 replicas with an Acerbis DOT headlight, and taillight. It retains a full charging system with a Ballistic Battery and Trail Tech digital gauge. Sprockets and an O-ring chain from JT Sprockets round out the final drive. The two tool/luggage bags on the rear fender are Wolfman.

“I ride mostly sand roads here in south central Kansas, and it is really fun exploring all the desolate back roads.” -Jim Platek, Wichita Kansas

#Yamaha Posted in: Do the Ton
rayplatek.rp@gmail.com April 17, 2017 at 7:33 PM
Looking good Jim, can't wait to ride it.
Building bikes, runs in the family!