Viper XTX clutching thoughts needed

[subaru2006]

my setup: stock gearing, ulmer stage 1, with performance package 4 and a machined secondary.
primary spring- o-p-o
weights 5oy
heel- t1
mid- 0
tip- 1-0

secondary spring- red
helix- h
spring wrap- 6-2

top speed 92 by gps and gauges are dead on. max rpm 8800 in perfect conditions. 85-90mph consistently. i don't hit the rev limiter on take off, i hit around 5500-6000 max and then it climbs to 8700 or so and drops down and climbs back up to around 87-8800.

my issues are and i know most will say to speak with ulmer which i will just not today. i don't know what i should be hitting for rpm and speed. i now have a lot of belt dust compared to before using the 8jp and no mods. i have a studder around engagement and not sure if that's due to the belt marks its leaving low in the primary. i wiped it with my finger and you can see it in the pictures. kind of feels wavy like the primary sheave doesn't go straight out at an angle but tapers some and then some more. that could be normal as i haven't dug into clutches before as much as i have on the viper. it feels like slowly apply throttle on ice and then catching snow (traction) and then going. here are a few pictures. the secondary is hard to see, i will get a better picture when i take it off. but that dark brown goes up and 1" or a little more from the shaft(center). only 400 miles so far.

primary



secondary

 

[Studroes144]

I think a lot of people are seeing that the red spring needs to be adjusted on the looser side (6-1 or 3-3) with the tighter wrap it may be keeping the secondary clutch from shifting and giving you the burn marks, when you wack the throttle no matter what speed you're at you want it to go right to the 8800-9000 range

 

[subaru2006]

i can hit the same rpm range every time i hit the throttle above idle, 86-8800 tho. i thought it might be the primary weights but got into thinking about shifting of the secondary after seeing the dark brown in the secondary. but if the secondary wasnt shifting fully wouldnt the burn marks on the primary be higher on the sheave and not lower like the picture? unfortunately i wont beable to test the less of a wrap due to no snow here in illinois and will be back in the UP in a couple weeks.

subaru2006

I think a lot of people are seeing that the red spring needs to be adjusted on the looser side (6-1 or 3-3) with the tighter wrap it may be keeping the secondary clutch from shifting and giving you the burn marks, when you wack the throttle no matter what speed you're at you want it to go right to the 8800-9000 range

 

[Yamadog]

It is hard to see from the pics but how much deflection do you have? It looks as if the belt is arched pretty high ( maybe camera angle). I had Ulmer machine everything and then I added the belt tension adjuster and have the belt set to just shy of creep at idle, I almost have a noticeable squeel. I have found this made mine launch and shift out much better. It does appear that your primary is spinning on the belt like there is not enough pressure on shift out but could have started with a little oil or grease on the belt or sheaves and once the problem started it just kept getting worse. You could be getting the belt hot enough on the primary that it is leaving residue on the secondary.

You should be seeing 8700 ish right after launch and it should stay there. It sounds like you are starting out in too high of gear and it takes a bit for the secondary to catch up. You would think if it was slipping it would over rev at launch.

I am at 252 hp and still running 8jp belts until I blow up my inventory and 300 miles on the setup now and they are as clean as when I got it back from Ulmer.
Last season with 8jp and Hauck overdrive sheave I was blowing belts every 150 miles. The one that is on it now has 500 on it.

With the 8dn machining of secondary to take up for the difference in belt length/thickness your assuming that the deflection is correct with the tensioner you can fine tune down to just shy of creep.

if you can clean both clutches and try another belt keeping that one for spare after cleaning it good.

 

[subaru2006]

i had a bit of an issues to start with and it was corrected. never cleaned the clutches but the secondary looked same before and after. the primary had 1 black line and the belt didn't go as high as it does now. deflection seems a little loose but i haven't put it on a stand. the belt sits on the secondary flush to just a little above. just barely pushing on the belt i probably have closer to an 1.5" maybe a little more. i have all washers still removed from the deflection screws. i don't hit 8700 until it builds. its hard to look at while launching but it could see it around 5-6 before i had to look up. i also didn't look down soon as i punched it either. conditions were far from perfect since it was snowing the entire time in the UP and always had a dusting on the trails. along with the warmer mushy snow. i will get it on a stand this week sometime and get back about that. the comment about oil or grease, not sure it was a brand new belt but ive never had a problem before with a new belt. i usually wash them. i don't always wash them but still never seen that. what do you guys think about the wavy sheave feeling? did the belt do that? or is it suppose to be like that.

subaru2006

 

[DC5]

If you have all the washers removed your deflection is way to loose.

 

[subaru2006]

That's what another thought of mine wash. I was on the trail and unable to get any washers. The belt sits fine in the secondary like that tho. I'll get it on the stand this week and make sure its OK.

Subaru2006

If you have all the washers removed your deflection is way to loose.

 

[DC5]

Typically with the 8dn at correct deflection it should be around an 1/8" out of the secondary.

 

[Yamadog]

Yup mine before the adjust was machined but needed washers for the 8 dn 0 for the 8JP I would clean them add at least one washer each bolt to get deflection correct. Remember the 8dn has to ride high in the secondary due to the width difference.

 

[Yamadog]

another thought are you sure the secondary is wound correctly? over wound will cause it to bind also

 

[newtron]

You need at least 2 washers in the secondary to run the 8dn. I currently run 3

 

[subaru2006]

Initially is was wrapped by ulmer. It was messed up so I'm not sure how the dealer in the up wrapped it after they fixed the problem. How can I tell minus taking it off?

Subaru2006

another thought are you sure the secondary is wound correctly? over wound will cause it to bind also

 

[Srxspec]

Your belt/clutch marks is coming from loose belt tension. Reset your belt tension by adding 1 thick washer back onto the bolts. Don't worry about how much belt sticks out of the secondary, that is not an accurate measurement, you must press down with two fingers on the belt in between the primary and secondary clutch, you should have approximately 1-1/8" of movement (belt deflection) this is the proper way to set it.

What were the conditions you were running on the weekend? Any loose snow will slow down top speed and so will warmer temps.

 

[subaru2006]

temps were around 30 for the most part and mushy loose snow along with new falling snow. had fresh 1-3" every time we got back on the trail. i couldnt bust 92 by gps. it was tough getting there, but the pull to 85-90 was insane. felt dead at 90 tho. not sure what i should be getting with the xtx gearing. i will adjust the deflection and run it on my stand and see. wont be able to ride with no snow here at home. ill be back in the UP in a couple weeks tho.

subaru2006

Your belt/clutch marks is coming from loose belt tension. Reset your belt tension by adding 1 thick washer back onto the bolts. Don't worry about how much belt sticks out of the secondary, that is not an accurate measurement, you must press down with two fingers on the belt in between the primary and secondary clutch, you should have approximately 1-1/8" of movement (belt deflection) this is the proper way to set it.

What were the conditions you were running on the weekend? Any loose snow will slow down top speed and so will warmer temps.

 

[subaru2006]

ok got the replacement secondary installed you sent, i also have the washer in the adjustment screws. belt sits a little higher in the secondary and belt deflection looks much much better. i have really no snow here just a heavy wet coating on the ground but i was able to go run it around with what you told me to do. maybe 300-400 foot straight. first is i was able to see 9200 on the rpm and my primary shifts to about a 1/2" from the outside but i don't have enough room to run it out. the low speed slip jerk is gone. so far so good. engagement is around 3400 rpm. i will really be able to tell if snow every falls here, if not i will be heading back up north soon.

subaru2006