This is a lightweight motard bike. Now all you closet DR350 owners can come out from under your rocks! Here's a pic of the dyno chart with various supporting runs.
I'll run down my list of mods first. DR350, Cycle gear 400cc piston, megacycle cam and springs(not the monster lift Web cam this one is a little more sedate), Cobra exhaust with oversized header all wrapped up with heat tape. Mikuni TM36 carb with a 4x6 inch K&N filter on it. just a light cleanup in the head with no port size difference. All transition areas were matched so there's no steps anywhere. That's about it for engine mods. Gearing was 14/46 and all dyno readings were taken in 4th gear.
warrior.bikepics.com/pics/suzuki-rm250-90-bikepics-045204.jpg
warrior.bikepics.com/pics/suzuki-rm250-90-bikepics-045205.jpg
Anyway, first run is the engine with the stock cam and springs. Netted me a 32.7hp and 25.9 tq. That was with regular pump gas too.
Rejetted with the cam and springs gave me an increase to 34 hp or a 4% increase at peak, however the peak with the cam occured at 500 rpm LESS than the stock cam. The cam kept pulling higher toward redline and actually pulled almost 4 more hp when the limiter cut in.
The last 2 lines are with VP Fuels Ultimate 4 racing fuel. I went one size up on the main to compensate for the oxygenated fuel and netted a .7 hp gain. the dyno operator also runs a motard bike (DR-Z no less) and ran MR2 fuel last year. He said the bikes like to run around 12.5 with the oxy fuel, so I went up to a 230 main. The helped me to pick another .6 hp. Then I ran out of gas (literally) and was done for the day.
What I like is the torque spread, from 3500 to 7500 the torque is at least 24 ft/lbs. It still pops like a sumbeyatch when I back off the gas though(no, there are no airleaks).
I think I will try to get a leaner needle to help smooth that dip in the torque, the mix would richen up in that area despite the needle adjustments I made.
I realize this is an old pig of a bike, but it shows what you can do with a little work. I think with wheels brakes, RM USD forks and everything I've got less than $2k into it, that includes the purchase price of the bike.
I'll run down my list of mods first. DR350, Cycle gear 400cc piston, megacycle cam and springs(not the monster lift Web cam this one is a little more sedate), Cobra exhaust with oversized header all wrapped up with heat tape. Mikuni TM36 carb with a 4x6 inch K&N filter on it. just a light cleanup in the head with no port size difference. All transition areas were matched so there's no steps anywhere. That's about it for engine mods. Gearing was 14/46 and all dyno readings were taken in 4th gear.
warrior.bikepics.com/pics/suzuki-rm250-90-bikepics-045204.jpg
warrior.bikepics.com/pics/suzuki-rm250-90-bikepics-045205.jpg
Anyway, first run is the engine with the stock cam and springs. Netted me a 32.7hp and 25.9 tq. That was with regular pump gas too.
Rejetted with the cam and springs gave me an increase to 34 hp or a 4% increase at peak, however the peak with the cam occured at 500 rpm LESS than the stock cam. The cam kept pulling higher toward redline and actually pulled almost 4 more hp when the limiter cut in.
The last 2 lines are with VP Fuels Ultimate 4 racing fuel. I went one size up on the main to compensate for the oxygenated fuel and netted a .7 hp gain. the dyno operator also runs a motard bike (DR-Z no less) and ran MR2 fuel last year. He said the bikes like to run around 12.5 with the oxy fuel, so I went up to a 230 main. The helped me to pick another .6 hp. Then I ran out of gas (literally) and was done for the day.
What I like is the torque spread, from 3500 to 7500 the torque is at least 24 ft/lbs. It still pops like a sumbeyatch when I back off the gas though(no, there are no airleaks).
I think I will try to get a leaner needle to help smooth that dip in the torque, the mix would richen up in that area despite the needle adjustments I made.
I realize this is an old pig of a bike, but it shows what you can do with a little work. I think with wheels brakes, RM USD forks and everything I've got less than $2k into it, that includes the purchase price of the bike.
