Viper Belt Slip/Clutch issue

S

SXviperER

New member
Joined
Sep 8, 2012
Messages
58
Age
37
Location
Ontario
Don't want to thread jack but went for a ride tonight in some freshly groomed trails/powder runs as experienced somewhat of the same problem. It was -28 degree C (-18F) and the sled was running great but sometimes the revs would rise up without any speed increase and think I saw 9k on one pull. I think I saw 45mph at roughly 6k rpm and 50 at 6.5k rpm. The only things I've changed from last year is a rebuilt secondary and a new belt (blew the old one last season). After the ride I touched the sheaves on both clutches and the belt and everything was cool. One thing I noticed is that I might not have the appropriate amount of play on the secondary shaft. I've attached a pic to show how many spacers are installed and also how far down the belt sits. Any ideas would be greatly appreciated.


 
One more thing. New belt has 200 miles on it and the over revving seems to be from belt slip but the belt is always cool to the touch. Thanks,
 
Yes, secondary should have some play side to side (1/8" or so) so it can self align with the primary. Belt should be sitting (I think) 1.5mm above secondary, yours looks about right. What do the rpm's go to if you pin the throttle? If it's stock probably around 9,000. The occasional 9k could just be track spin. Did you wash the new belt before you used it?Is the belt glazed on the edges? Generally with belt slip comes heat on the clutches.
 
Is it just the way the pic looks or is that belt not flat in the clutch? Looks higher on the outside? Maybe too many shims, not enough free play?
 
It was hard to take the pic. If I have too many washers on the secondary shaft or behind the sheaves could this cause my problem?
 
Check for CTC and offset. The belt height looks good to me, even though at first glance I wondered. All that is above the sheave is about 3/4th's of the outside cogs. Look closely at the very top of the pic and you can see that what looks like belt is actually the edge of the sheave. The inside belt height looks about the same.
 
What belt are you running? The 8DN belt is hard as a rock and slips a lot. The Carlisle xs-805 is the belt of choice. That yammie is good to carry as a get home belt, but it leaves a lot on the table performance-wise.
 
Can I really blame the slipping to a harder compound belt? The belt picture leaves a lot to the imagination. The far end of the pic is a true picture of how the belt sits. If that's not my problem would removing a spacer on the secondary shaft increase the belt tension? Clutching newby.
 
Sorry. Running an 8DN. Belt is always cool to the touch and no deposit on the clutches.
 
Last edited:
With all due respect, I disagree with the thought that a harder belt loses any significant performance. IMO this is only true if your clutches are tuned for a softer belt that requires less side pressure, and you try to run a harder belt. If the clutches are tuned for an 8DN then I would run an 8DN. The 8DN is a very durable belt that when adjusted properly will provide long life and excellent performance.
 
I believe the spacers you are referring to are the ones on the shaft itself. These do not affect belt deflection, but rather the side play amount that the secondary has on the shaft. What a previous poster might have been referring to are the washers on the backside of the secondary that affect how far the secondary can close. First make sure your side play is correct (adding or removing washers). Then adjust CTC and offset of the clutches. One thing about the Viper is that it does not come stock with an engine torque arm. Not only does the engine twist under load, but it can also break motor mounts. I prefer to add a SRX torque arm and lock it down tight. Then I don't need much side play in the secondary. Grab your engine and see if you can twist it around in the sled. This will let you know if it can twist under load.
 
I dont think you have a problem at all, most people skimmed right over the fact you were riding the sled at -18 below zero,SO...if it was still jetted stock, she woulda been running real crisp and making a bit more power at that temp, your only over revving 300-400rpm.

I bet if you run it again at more normal winter temps it will be fine as all the rest of the stuff you listed is fine for specs,and the clutchs look to be clean.
 
Rode on warmer day and everything was good. The only thing i noticed is that the belt isnt very tight. I feel as if i could raise it out of the secondary a little. Problem is i'd need to get washers and cant exactly figure out where to install them. I've used the search function and cant turn up a good pic or walkthrough.
 
If someone could point me in the direction for setup on a secondary it would be greatly appreciated.
 
SXviperER said:
If someone could point me in the direction for setup on a secondary it would be greatly appreciated.
Click to expand...

if you want to tighten up the belt deflection, you have to remove the 14mm headed bolt holding on the sec. clutch, then pull off the clutch and flip it over, youll see (3) 8mm headed bolts on the back of it, youll add a washer to tighten up the belt deflection.
 
Spec is .5MM below to 1.5MM above the secondary sheave.

Also the 2002 Vipers in stock form were known to be clutched a little light, they would see 9000 rpm in the right conditions.
Not good over reving, making noise and not going any faster .....
 
You must log in or register to reply here.


Back
Top