Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: RM250 Evan on January 10, 2011, 12:01:51 AM
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Hey guys just got my MXA February issue. Inside they answered a question about the 07 Rm250, so I thought I would share.
"Dear MXA,
I have a 2007 RM250 that I have been racing and would like to improve if possible. What can you tell me about the 2007 RM250 two-stroke?
In 2007, Suzuki tilted the RM250 engine forward. They didn't do this to lower the engine, but to raise the counter-shaft sprocket by 3mm to alter the chain torque. The 2007 RM250 engine was a Yamaha clone on terms of cylinder layout and porting. The 2007 RM250 benefited from a Pro Circuit pipe and V3 reeds. The gearing was spot-on. We liked the stock shock, but ran a pro circuit linkage because it stiffened the initial part of the shock's stroke and lowered the rear of the bike by 12mm, which allowed us to raise the forks enough to lower the complete chassis." (MXA)
Learned something new today. ;D
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Except you would have to rotate the engine back to raise the countershaft, tilting the engine forwards, lowers the countershaft, and effecting pro or anti squat in the rear.
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Except you would have to rotate the engine back to raise the countershaft, tilting the engine forwards, lowers the countershaft, and effecting pro or anti squat in the rear.
Assuming the pivot point was the swingarm bolt, what if the pivot point was the engine mount on the bottom of the frame, rotating the engine foward would raise the countershaft sprocket.
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The rear motor mount is also the swingarm pivot point,to raise the rear of the motor you would have to change the centre case castings.When the front of the motor was lowered the crankshaft centre line was also lowered which changes the turning characteristics - hence the PC link.
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Except you would have to rotate the engine back to raise the countershaft, tilting the engine forwards, lowers the countershaft, and effecting pro or anti squat in the rear.
Assuming the pivot point was the swingarm bolt, what if the pivot point was the engine mount on the bottom of the frame, rotating the engine foward would raise the countershaft sprocket.
X2.Exactly so.
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link shmink, get a friggin revalve.
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Except you would have to rotate the engine back to raise the countershaft, tilting the engine forwards, lowers the countershaft, and effecting pro or anti squat in the rear.
Assuming the pivot point was the swingarm bolt, what if the pivot point was the engine mount on the bottom of the frame, rotating the engine foward would raise the countershaft sprocket.
Read the original post says "didn't do this to lower the engine" if the engine is pivoted around the swing arm bolt how will lowering th engine RAISE the countershaft?
What it does is raise the swing arm pivot.