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Old 10-08-2012, 07:01 PM   #7505
Joined: Jul 2005
Location: Traveler
Oddometer: 5,218
Originally Posted by Aussie Steve View Post

Actually got one on order.

If I read the reason you have added the flow info correctly you are thinking it could be the cam kicking in at 5000rpm? Had a little experience owning cars with cranky cams and the way this changes bang on at 5000rpm regardless of throttle or load makes me think timing advance changes at that point, its also a crisp edge unlike a cam which ramps up a little slower.

I agree that a faulty plug or cam timing out a bit would make this much more noticeable.
Actually I stuck it in just to show how complex tuning can be.
Not sure what year your mc is, does it have the hi-flow head?
As for the rally cam, my guess is that the factory riders just beat the engine and never let it under 5k rpm.

It's an easy habit to get into, even with my stock machine, stock jets, modded exhaust it works best to run 4k+ for rpms.
I think it's easier on the engine.

If I was you with the rally cam I would open the exhaust system or find an Akrapovic. What carb are you using?
'02 KTM 640 Adventure-lowered
"On the road there are no special cases."
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The faster it goes the faster it breaks.
And high performance=high maintenance.
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