hammerhead251
Member
- Feb 23, 2004
- 10
- 0
Major props to Eric and Rich for a great job and good advice.
This is the bike to replace the 525.
99mm piston, 11:1
Stroker crank (78mm)
EXC counterbalancer
1mm oversized Kibblewhite valves
Headwork by Forward Motion
Stock carb bored to 43mm
Stock jetting, no BK Mod
Hotcams 525 cam
Drilled airbox cover
Stock pipe w/can shortened 2.5 inches (due to race damage)
14/48 gearing
Comes out to 600cc even. KTM should sell it.
Thumper Racing did the cylinder, aluminum sleeve welded and machined in stock 520 cylinder, then chromed. I wanted the compression low to help top end (God knows, it doesn't need any more bottom). With this piston/cylinder kit, there is no case boring needed. Sweeeet!
I put it all together and it started third kick (I swear). Now it starts 1st or 2nd kick every time, and the bike isn't any harder to kick than the 525.
This is the smoothest, fastest bike ever. I've only timed three laps so far on my practice track, and one was even with my best lap ever, the other two were 1 and 1.5 seconds FASTER!
With this gearing, I am running 3rd and 4th everywhere. This bike pulls the same gear in the same corners as my 450 which has 13/48. 2nd gear is pretty scary with this bike. If I ever need more speed, 15 front and/or 45 rear should be no problem.
The most amazing thing to me is the throttle response. I expected the worst, but this bike is actually better than my 450 and 525 in rhythm/technical sections. I guess the 99mm bore pushes that big crank around pretty efficiently and 600cc draws plenty of velocity through the giant carb. Blip the throttle and she jumps!
I'm taking 'er to Birch Creek this weekend for the Ultra/Mega/US Eastern/whatever else series race. We'll see how she races. I also plan to have dynos done with different pipes and against my stock 525, my 470SX, and a stock 450SX.
Stay tuned.
This is the bike to replace the 525.
99mm piston, 11:1
Stroker crank (78mm)
EXC counterbalancer
1mm oversized Kibblewhite valves
Headwork by Forward Motion
Stock carb bored to 43mm
Stock jetting, no BK Mod
Hotcams 525 cam
Drilled airbox cover
Stock pipe w/can shortened 2.5 inches (due to race damage)
14/48 gearing
Comes out to 600cc even. KTM should sell it.
Thumper Racing did the cylinder, aluminum sleeve welded and machined in stock 520 cylinder, then chromed. I wanted the compression low to help top end (God knows, it doesn't need any more bottom). With this piston/cylinder kit, there is no case boring needed. Sweeeet!
I put it all together and it started third kick (I swear). Now it starts 1st or 2nd kick every time, and the bike isn't any harder to kick than the 525.
This is the smoothest, fastest bike ever. I've only timed three laps so far on my practice track, and one was even with my best lap ever, the other two were 1 and 1.5 seconds FASTER!
With this gearing, I am running 3rd and 4th everywhere. This bike pulls the same gear in the same corners as my 450 which has 13/48. 2nd gear is pretty scary with this bike. If I ever need more speed, 15 front and/or 45 rear should be no problem.
The most amazing thing to me is the throttle response. I expected the worst, but this bike is actually better than my 450 and 525 in rhythm/technical sections. I guess the 99mm bore pushes that big crank around pretty efficiently and 600cc draws plenty of velocity through the giant carb. Blip the throttle and she jumps!
I'm taking 'er to Birch Creek this weekend for the Ultra/Mega/US Eastern/whatever else series race. We'll see how she races. I also plan to have dynos done with different pipes and against my stock 525, my 470SX, and a stock 450SX.
Stay tuned.
