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Clutch engagement-911 cover?

TD Max

TD Max

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Mar 5, 2014
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2,282
Location
Central WI/Hazelhurst WI
I've never liked the engagement on my Viper. Hard to tell if its throttle control related or clutching, but you can't creep up on it. It seems to hit a point then take off. Almost acts like a notched weight but with engine response so touchy I have to wonder could it be partly clutch weight related as well? Wondering about shimming the movable sheave closer to the belt to give the weights better angle when they first contact? Probably simplest with a 911 cover and use the adjuster?

Has anyone used this method to smooth out engagement?
 

I simply adjusted the deflection on my belt last season and it made a huge difference on take off. I have the Thunder Products clutch kit which addresses the issue of rough take off ( I never rode it stock so I do not have a comparison) but still found it to be too rough at take off. I have always run my belt high on the secondary so the bottom of the notch is level with the top of the sheave but lowered it so the top of the belt is level with the top of the sheave and now it is much better in the parking lots. I know Barn of Parts also sells a soft start primary spring that others have had good luck with.
 
I heard replacing the primary clutch spring with a White Pink White was a good OEM replacement for soft start with same finish as stock:

" Using any yamaha spring with an initial preload of 30kg will give you a smooth engagement between 2800 and 3000RPM.
But if you want to have the same finish rate than your stock spring then use the white-pink-white spring #90501-583L5-00."

https://ty4stroke.com/threads/soft-start-yamaha-primary-spring.151716/#post-1410096

Also BOP offers an aftermarket soft start spring as well.

I put a white pink white spring in this year and I'm now pleased with clutch engagement. Much smoother and lower RPM.
 
FYI I run OYO right now which I believe is 30kg start. Also have OPO which if memory serves is 35kg.

I'm working on my weights right now and it seems that dropping 2g from the heel made a nice improvement. I could stand to lose more heel weight so we'll see what that does.
 
I had the BOP spring which worked great on engagement i know have the Ulmer Kit and not happy with engagement his kit has almost all the weight in the tip of the arm which seems strange to me. sled pulls hard but my MPG dropped pretty bad carries lots of RPM just cruising along like it doesn't shift up. I may add some heel weight to drop engagement and hopefully what it runs when just cruising. Hoping I don't add to much that i loose RPM. What sucks is its 4-6 hr ride each weekend for us to get to snow and that point you just want to ride not test.
 
SeX Viper said:
I simply adjusted the deflection on my belt last season and it made a huge difference on take off. I have the Thunder Products clutch kit which addresses the issue of rough take off ( I never rode it stock so I do not have a comparison) but still found it to be too rough at take off. I have always run my belt high on the secondary so the bottom of the notch is level with the top of the sheave but lowered it so the top of the belt is level with the top of the sheave and now it is much better in the parking lots. I know Barn of Parts also sells a soft start primary spring that others have had good luck with.
Click to expand...

This is what you need to check first, deflection.
If the deflection isn’t tight, your take off will be harsh. Set it and then decide if you need a softer primary spring. You certainly don’t need a 911 cover to have smooth engagement.
 
ClutchMaster said:
This is what you need to check first, deflection.
If the deflection isn’t tight, your take off will be harsh. Set it and then decide if you need a softer primary spring. You certainly don’t need a 911 cover to have smooth engagement.
Click to expand...
Don't need it but it helps especially if you run old worn belts or can't find the widest ones!
 
TD Max said:
FYI I run OYO right now which I believe is 30kg start. Also have OPO which if memory serves is 35kg.

I'm working on my weights right now and it seems that dropping 2g from the heel made a nice improvement. I could stand to lose more heel weight so we'll see what that does.
Click to expand...

Removing heel weight will make it engage at a higher RPM than what you currently have. You need to ADD heel weight to lower engagement RPM or run a spring with a lower initial preload.
 
TD Max said:
I've never liked the engagement on my Viper. Hard to tell if its throttle control related or clutching, but you can't creep up on it. It seems to hit a point then take off. Almost acts like a notched weight but with engine response so touchy I have to wonder could it be partly clutch weight related as well? Wondering about shimming the movable sheave closer to the belt to give the weights better angle when they first contact? Probably simplest with a 911 cover and use the adjuster?

Has anyone used this method to smooth out engagement?
Click to expand...

I agree that proper belt deflection is the first step to take. To answer your question, Yes , proper side clearance will make a huge difference toward a smooth engagement. I had been looking for a primary adjuster for quite a while and couldn't find one. I broke down this year and added the 911 cover just for the adjuster. The engagement is now like butter. Very nice piece !!
 
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