Surging at full throttle over 60 mph

[Mills]

I have a 2014 Viper RTX and recently it started to surge in speed when over 60 mph and at full throttle. I have the primary/secondary clutch kit from Ulmer in it and the 2019 re-flash that raises the rev limiter to 9300. I am hitting around 9150 rpm so I am not hitting the rev limiter. I tore the sled down and went through the bearings and chain case. All bearings were good and I had to put about 3.5 turns into the chain tensioner to get it finger tight. Could the surging have come from the chain being to loose at 60 mph or higher speeds and then trying to accelerate more with full throttle application? I also noticed that the air box was coated with oil from a slight right side tip/roll over but it was not pooled in the air box. Could this have had something to do with it?

 

[cannondale27]

I would suspect the sparkplugs.

 

[Tonyb5343]

I have a 15 with the mpi turbo kit and I notice I surge as well at wot above 50/60 mph like the power comes in and out, it isn’t smooth , is that what your referring too?

 

[Mills]

I have a 15 with the mpi turbo kit and I notice I surge as well at wot above 50/60 mph like the power comes in and out, it isn’t smooth , is that what your referring too?

Yes that is exactly what it feels like.

 

[Mills]

I would suspect the sparkplugs.

My sled currently has 3,500 miles on it and I have never changed plugs. I am coming off of my '08 Nytro that had 8,800 miles on it without a plug change and no plug problems. I have heard many Viper plug issues, what is so different between the Nytro and Viper that would cause the Viper to have plug issues but not the Nytro with the same motor?

 

[rbell14]

I've got 6,000 on original plugs, changed them a month ago just because but they looked good. I've not heard of plug issues on Vipers.

 

[cannondale27]

My sled currently has 3,500 miles on it and I have never changed plugs. I am coming off of my '08 Nytro that had 8,800 miles on it without a plug change and no plug problems. I have heard many Viper plug issues, what is so different between the Nytro and Viper that would cause the Viper to have plug issues but not the Nytro with the same motor?

All it takes is one batch of bad gas or one startup where its not fully warmed up to ruin a plug. Its been that way with ALL Yamaha snowmobiles that has not changed other than alot more crappy fuel out there.

 

[Mike P]

All it takes is one batch of bad gas or one startup where its not fully warmed up to ruin a plug. Its been that way with ALL Yamaha snowmobiles that has not changed other than alot more crappy fuel out there.

X2

 

[Mills]

All it takes is one batch of bad gas or one startup where its not fully warmed up to ruin a plug. Its been that way with ALL Yamaha snowmobiles that has not changed other than alot more crappy fuel out there.

Stick with stock plugs or is there a better plug to use in these 4 strokes?

 

[cannondale27]

Stock