Ulmer clutch kit issue.

[Burnzy]

I bought a 14 viper ltx with only 170 miles on it. Previous owner installed ulmer clutch kit, k/n air filters and changed belt to 8dn last season. 144 studs. no turbo. previous owner and i are close to same weight. First ride on the sled a couple weeks ago, this thing was a rocket up to 60mph. but from 60 to 75 it simply ran out of "gear". Top speed never broke 80 and motor was turning 9k. Something isn't right. I'm not a "clutch" guy so this is all new to me. Sled is at my dealer right now but having trouble getting ulmer to call back. Does anyone have any idea what could be wrong? It feels like something isn't shifting, and i noticed when holding it at a consistent speed the rpm's never really back down either. My mechanic said he took it all apart and everything looked to be correct except the weights in the primary were "sticky". Getting frustrated. I'm not a lake racer but it should run faster than this is stock form. Any suggestions would be appreciated. thanks in advance.

 

[titanrcr]

At only 170 mi I wouldn't be too concerned about top end but 9000 rpm sounds a bit high. That engine will gain a good amount of power and rpm as it brakes in. I would get through your brake in and than address you clutching.

 

[Burnzy]

Sled has 785 miles on it now and nothing changed.

 

[TD Max]

Take a look at the various threads regarding Viper top speeds. They are VERY condition sensitive and can be quite frustrating. Sounds like the clutching is doing it's job the conditions are just holding you back. Tat is of course assuming the secondary is not binding etc which the mechanic seems to have verified.

 

[titanrcr]

Sled has 785 miles on it now and nothing changed.

You are well into the brake in at that mileage. When you say the rpm won't drop down while at a consistent speed and primary weights are "sticky" that could be an area for concern. Maybe you know of someone else who could have a look at the clutches for you ?

 

[Studroes144]

There's been many cases of Yamaha clutches that bind up due some slag left on the clutches from factory. Nospro has a couple videos in the FAQ regarding this as well as clutch cleaning. I had a cat 7000 do the same exact thing, rocket to 85 then it's like u put the brakes on and it would not gain, even in perfect conditions. Dealer took the primary clutch apart and cleaned it in the places it was tight and went out that day and went 99mph, my guess is your issue is with the clutch itself and not the clutch kit.

 

[stingray719]

There's been many cases of Yamaha clutches that bind up due some slag left on the clutches from factory. Nospro has a couple videos in the FAQ regarding this as well as clutch cleaning. I had a cat 7000 do the same exact thing, rocket to 85 then it's like u put the brakes on and it would not gain, even in perfect conditions. Dealer took the primary clutch apart and cleaned it in the places it was tight and went out that day and went 99mph, my guess is your issue is with the clutch itself and not the clutch kit.

Yep, and some including one of ours had belt dust from the original 8JP foul up the primary. Dust gets into the bushings and primary gets sticky. Easy to check, take off belt and cover and see if it goes all the way in and back easily by hand. If so polish shaft and clean clutch with compressed air and soap and water

 

[stingray719]

Lots of info in this thread,
http://www.ty4stroke.com/threads/post-your-clutch-setup.132429/

 

[Studroes144]

Yep, and some including one of ours had belt dust from the original 8JP foul up the primary. Dust gets into the bushings and primary gets sticky. Easy to check, take off belt and cover and see if it goes all the way in and back easily by hand. If so polish shaft and clean clutch with compressed air and soap and water

Exactly! Getting familiar with your machine and doing simple cleaning and maintenance will be very rewarding!

 

[yamahaguy]

Last year at a TY ride my XTX LE would top out at 75ish mph with the same clutch kit with the 8jp belt. I mostly ride off trail so top speed is not big deal for me but I always thought the sled should be faster then 75ish mph on good snow conditions. Some good friends suggested removing the kits secondary spring and installing the original OEM secondary spring back in and setting it to 6-2 so we switched it right in the parking and made no other changes. The sled will do 96 mph without breaking a sweat now with one simple change. Lots of great ideas here from the others, so let us know what you/dealer find.

 

[ClutchMaster]

Put it on a stand and take it up 90 mph watch the clutches while you are cycling between 90 and 60 mph. If they are sticking you will see it. When you get on and off the gas. Clutches should open and close smoothly.

 

[ClutchMaster]

Yamaguy,
How are you rpms and mid range with the stock secondary spring? It's a white correct?

 

[NOS-PRO]

Yamaguy,
How are you rpms and mid range with the stock secondary spring? It's a white correct?

No, I installed the Pink back in Yamahaguys sled and wrapped it 6-2. His rpms went down cause he was htting the rev limiter. The sled rocks now!

 

[ClutchMaster]

Pro was it Ulmers red spring?

 

[yamahaguy]

Pro was it Ulmers red spring?

Yes, it was the red spring that was removed, Then the stock Pink spring was put back in and been there ever since.