The bike made it into the CycleWorld Reader’s Collection in the Minneapolis show in 1995. The project went like this.
In 1990 I wanted to build a project bike…an inexpensive Friday night head-turning custom. So, I put an add out for a Suzuki GT250
and one week later I had my bike. It started life as a 1974 Suzuki GT250 with 4,500 miles on the clock and a dent in the tank.
Expansion Chambers were also fabricated by me and a special thanks to Gordon Jennings and the “Two Stroke Tuner’s Handbook” for the science and calculations behind them. They work great. They come on hard by 5,500 rpm and tail off about 7,500 rpm (500 shy of redline).
The pipes were designed based on design theory laid out by Gordon Jennings in the Two Stroke Tuner’s Handbook. Based on port timing and desired peak power rpm it laid out the physics and equations to lay out a basic pipe design. Shorter cones would give a narrower power band and long cones would give a very broad power band. I designed mine to be fairly broad (not to the off road scrambler level of the time though) with a peak power at 7,000. The bike redlined at 8,000 rpm. I laid out the cone design and started rolling cones. These are made from 22 gauge steel. They then had to be welded together to fit the routing on the bike. The headers are bent auto exhaust and originally the stingers were internal to the last cone but were removed in 2006. The silencers are aftermarket RZ350 cans with custom innards wrapped in fiberglass. The pipes start to come on around 4,000 rpm and pull hard to 7,000 where at 7,500 rpm it falls very flat on power. I don’t know if this is a pipe based limit or ignition or a little of each.
The fairing is a cut down 70’s aftermarket (liberated from the neighbor’s trash) with an early GSXR windshield cut to fit. The front fender is a 750 Intruder (crash victim). Forx Air Shocks. Silencer cans are aftermarket for an RZ350. Pods on the carbs of course. Tach is of unknown Suzuki origin, mounted with redline straight up. And of course....no speedo.
A trip to the machine shop with the top end got me a set of jugs with a 330cc displacement. Almost the perfect 1/3 liter two stroke. Since I had recently replaced all the crank seals in the 250 cases I didn’t want to start over so I did some research and found the stroke, crank, and rods, are the same between the T350 and the GT250. The only difference is the bore. I found in one of the books that you could bolt a T350 topend down to a T250 bottom end if you clearance cut the cases so the piston skirts would clear. When I check fit the T350 cylinders onto the GT250 cases I found that they had already modified the cases in the GT design (Or did they just use the T350 case design when they built the GT250???) The skirts cleared just fine! Presto GT250/T350!
The frame paint is a ’87-’90 Toyota Supra White Pearl Mica Metallic color and the body work is a ’89-‘91 Toyota Corolla Regatta Blue Pearl Metalic. Both have a clear over the top with the Suzuki stickers applied before the clear coat. The engine is PJ case paint which works great as long as the engine is clean enough to eat off of before you paint it!
For more pics of the orginal bike, build process, or finished bike click here!