A little setup help please

[kodak]

I have a 2014 viper xtx with hurricane Turbo and clutching setup at 0 and 1 on helix about 3 weeks ago did some riding in low snow conditions and sled was around 8900 max rpm and would lift the ski about 2 ft off ground in places where snow was a little deeper with ease. Last weekend in great snow conditions from 2 ft powder on ponds to 4 to 6 ft powder in back country max rpm was 8200 and ski would not lift off ground anymore than 3 inches on flat . Belt looked good but could be worn a little and has 900 km on it out . I just put a new belt on as I was leaving and without a helmet tried to check out max rpm and saw 8400 but probably could of had more but to risky without the beanie on when hit throttle from take off hit rev limiter . Not much snow to test on where I live but can a warn belt bring down rpm because I thought it would raise rpm and slip if warn. A little help and maybe some education on how belt wear affects rpms would be appreciated . I turbod the viper to do wheelies and catwalks so need help to get there . I will contact Dave from hurricane for help he has always been helpful and available but wanted to see if anyone had some insight into possible solutions and I do not feel this is a turbo issue but maybe more of a clutch or belt issue. Thanks my finger is tired now and needs some rest

 

[skidooslayer687]

You'll under rev in deep snow if it's been set up for a "trail/hard pack" condition

 

[Yamadog]

Well mine as the belt wears out hits the rev limiter more often due to slipping and the smaller the belt is width wise should allow the clutches to shift out faster I would think. If it stretches then it would effectively change the shift out of the primary being faster than the secondary causing the engine to over rev.

I can tell you that we ran into this a lot last season with our MPI's at 6#'s of boost some days we would see 9000 rpms and others were 8400. Mine was fixed by machining both primary sheaves for overdrive and the secondary to relieve spring bind and converting to 8 dn belt. Yamaha Tim had even more trouble with this in his LTX than I did with the XTX. We were both blowing belts about every 200 miles. I can teel you that my secondary is wound 6-3. With even a trail turbo at 180 hp you should not have a problem spinning the track in deep snow and lifting the nose.

 

[Studroes144]

Yamaha belts are very hard so when cold they'll slip a bit more. Once they warm up they grip better and will pull rpm down, but you'll want to clutch accordingly to full operating temps of the belt and clutches, not when the belt and clutches are cold, that can really throw u off

 

[STAIN]

My turbo also taps the limiter with a cold belt. 8JP belt with 4200 miles on it!!!

 

[ApexGTman]

I also have a rpm issue with my MPI turbo with Ulmers clutch kit on '15 RTX LE. I found on Hard Packed road it pulls like a freight train. But today on a snow covered lake, I could only hit 8100 and fall back to 7800 with top speed of little less than 70 mph.

Anyone have any suggestions, need some help please.

 

[Yamadog]

I have not but I would "assume" that in deep powder with spinning track especially the 1.25" It is spinning with no load on it and your primary is shifting out faster than the secondary throwing the ratio off and causing it to pull the motor down or if you did not machine the secondary for spring bind that may be happening on the secondary keeping it from full shift out. Is it the trail turbo or stage 1 kit?

I would email Allen he could tell you.

 

[ApexGTman]

I have not but I would "assume" that in deep powder with spinning track especially the 1.25" It is spinning with no load on it and your primary is shifting out faster than the secondary throwing the ratio off and causing it to pull the motor down or if you did not machine the secondary for spring bind that may be happening on the secondary keeping it from full shift out. Is it the trail turbo or stage 1 kit?

I would email Allen he could tell you.

It wasn't powder, just heavy snow. It has the 1.7" track and I don't think it had much track spin. The secondary is not machined. I sent Allen an email, just waiting for his reply.

 

[Yamadog]

oops sorry forgot you had the 1.7" track but im sure Allen will get it figured out. I was all over the place on rpms until he fixed mine. Spring bind is a problem but not sure why you guys are dropping that low on rpms mine would go to 8900 then drop to 8200 then rise to 8400 and stay there on lakes.

 

[ApexGTman]

oops sorry forgot you had the 1.7" track but im sure Allen will get it figured out. I was all over the place on rpms until he fixed mine. Spring bind is a problem but not sure why you guys are dropping that low on rpms mine would go to 8900 then drop to 8200 then rise to 8400 and stay there on lakes.

It is a trail kit, do you know what the fix was for you? I still have the stock 21/49 gears, going for a ride next week for a few days and would like to fix it, 111 km/h (69 mph) is just not going to cut it for a turbo'd sled. Maybe there's something simple I need to do?

 

[sxr70001]

You could try increasing your secondary wrap to see if that helps. Sounds like its shifting out too fast.

 

[kodak]

I was speaking to Dave and I am going to change my primary spring and shim my wastegate to increase rpm and add washers to heel of arms to keep off rev limiter at holeshot will try this over next week and report

 

[ViperRTX-Turbo009]

I have a

I also have a rpm issue with my MPI turbo with Ulmers clutch kit on '15 RTX LE. I found on Hard Packed road it pulls like a freight train. But today on a snow covered lake, I could only hit 8100 and fall back to 7800 with top speed of little less than 70 mph.

Anyone have any suggestions, need some help please.[/QUOTE

I have a hurrican turbo on the me, stick gearing is back in it, I had the same problems as you, try a. Stiffer primary spring, i did this an I'm right up at the 8800-9000 mark. In the soft snow I hit about 85-90 mph all day and on hard pack/ little snow I saw 96 mph- I'm going to get the clutches machined for next year and see how tht goes to. With the stick low gearing and a turbo it pulls like a freight train! Try and stiffer primary's spring and let me know how it works - I have Dave's clutch kit in just tried a couple diffrent primary springs till
I got what I wanted

 

[ViperRTX-Turbo009]

Rtx le as well
With a hurricane turbo. I had the same problem as you, try a stiffer primary spring. It worked for me, I'm
Pulling 8800-9000 in the snow and 9000 on the hard pack. In the snow I'm seeing anywhere from85-90
Mph and hardpack I saw 96 last weekend. Need to get the clutches machined for next year year tho! Try this out lemme know how it works for ya ! I have Dave's clutch kit as well tho not ulmers... But it's something to think about

 

[ViperRTX-Turbo009]

Shim your

I was speaking to Dave and I am going to change my primary spring and shim my wastegate to increase rpm and add washers to heel of arms to keep off rev limiter at holeshot will try this over next week and report

Shim
Your wastegate , me just curious what psi are you running before doing this ?