Clutch and Contra Spring

Troll · 01-15-2014, 10:19 PM

Just bought a VIP and the guy has installed the high rpm clutch and contra springs in the clutch. It has racing variater on it with 5gr weights in it. My problem is it's having to rev up to 6000 to 7000 rpm before it engages, I'm afraid is going to snap the belt. Any ideas on how to fix this? Now I do have another one with the red springs in it that's complete.

qwertydude · 01-18-2014, 02:00 AM

That's the problem with just randomly sticking parts in and hoping for the best. When performance tuning it's important to change only one thing at a time because you don't know how they'll all interact. In this case you've put all three things that tend to increase RPM's on take off, it's no wonder you're revving sky high before the engine even engages.

When you put strong contra springs you generally have to raise the roller weights to compensate. Also unless your belt was slipping from too much power the stronger contra spring just serves to rob power because it squeezes the belt too hard resulting in more friction. This also tends to wear out belts and roller weights faster.

On top of that light weight clutch springs do nothing for power all it does is make for snappy engagement off the line. They also tend to create more friction and heat and can cause wear and intermittent belt snapping.

Troll · 01-18-2014, 12:49 PM

I rode it yesterday for the first time for about a 80 mile round trip.It really seemed to do alright and the top end seemed good, just thinking for going up on the sliders to maybe an 8 gram to knock down the high rev or maybe mixing 5 an 6 grams, what do you guys think would be a better way to go?

qwertydude · 01-20-2014, 03:09 AM

Don't guess on weights. Buy a cheap digital tach-hour meter. They're only about $25 on ebay. This will tell you exactly what your engine is doing and how you'll need to change the weights. Generally keep the engine running about 7000 rpm, this leaves a little wiggle room because initial rpms on takeoff can rise higher than the cvt setpoint before settling.

01-18-2014, 02:00 AM	#2
qwertydude Join Date: Jan 2010 Posts: 139	That's the problem with just randomly sticking parts in and hoping for the best. When performance tuning it's important to change only one thing at a time because you don't know how they'll all interact. In this case you've put all three things that tend to increase RPM's on take off, it's no wonder you're revving sky high before the engine even engages. When you put strong contra springs you generally have to raise the roller weights to compensate. Also unless your belt was slipping from too much power the stronger contra spring just serves to rob power because it squeezes the belt too hard resulting in more friction. This also tends to wear out belts and roller weights faster. On top of that light weight clutch springs do nothing for power all it does is make for snappy engagement off the line. They also tend to create more friction and heat and can cause wear and intermittent belt snapping.
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01-20-2014, 03:09 AM	#4
qwertydude Join Date: Jan 2010 Posts: 139	Don't guess on weights. Buy a cheap digital tach-hour meter. They're only about $25 on ebay. This will tell you exactly what your engine is doing and how you'll need to change the weights. Generally keep the engine running about 7000 rpm, this leaves a little wiggle room because initial rpms on takeoff can rise higher than the cvt setpoint before settling.
	0