First Ride = Blown Belt. Fluke?

[YammieDave]

I bought a supercharged (stage 1 MPI, 180 hp) 09 Nytro 144" over the Summer, and last week was my first ride.

We were on a straight, snow-covered road going about 40, when my friend blew past me on the other Nytro I bought (stock, no boost.)

He was on it hard, so I figured this would be a great opportunity to see what a difference the boost will make. I'll get on it, reel him in easily and just blow by.

I punched it. To my surprise, I did not reel him in quickly. I was gaining, but nothing all that impressive. By the time I got to about 75 or 80, my drive belt just exploded.

So now I'm left thinking...

Was it just time for that belt? I hadn't measured it to tolerance before riding.

Or - was my lack of expected acceleration due to the clutch slipping under the high RPMs and high load, which heated up the belt quickly, and blew it?

I don't know if any clutching was done with this sled. I asked the seller if he did anything with clutching after putting in the supercharger, and (if I recall correctly) he said he didn't need to, that the performance was just great as it is. I believe I'm the third owner.

My question is: Is it imperative to mod the clutching with a supercharger? Am I justified in suspecting that the motor may be generating more power than the clutches can hold on to? I'm kind of scared to really jump on it at high speed now, because I don't want to cook another belt to find out.

Hoping for some good feedback from all the experience here. This is my first 4 stroker, and obviously my first supercharger. Rode redhead triples prior to this.

 

[AftonJay]

What belt was on there? How old was it? Was it the correct belt? If it was the belt that was on there when you bought it, it could have been subjected to tons of abuse. I would look at MPI's website or contact them and ask about recommended clutching for your elevation. Personally i like the Yamaha belts, on my old RX warrior that had a little work done i bought an aftermarket belt (high horse power super extreme whatever it was) and blew that thing on a 3/4 throttle blast off. Put on a Yamaha which was actually cheaper and never blew another one.

 

[YammieDave]

Yeah, thanks, forgot to mention that it was an 8DN belt. I'm just not sure where it was in wear width. Visually , it looked fine.

There's a new 8DN on it now, but I haven't pushed it.

 

[InRBigness]

make sure you break in the new belt well before you go at it hard. I would think that it was belt slippage from a used belt.

 

[YammieDave]

Yeah, will do that. Running around at high speed isn't exactly my style anyway, mostly going from 0-40 as fast as possible while boondocking.

I also checked clutch alignment, that looks good.

 

[DTJ]

I would sure think some weight would need to be added to the primary with the super charger. I put just a can on my nytro and was hitting the rev limiter. If no clutching from stock had been done with the super charger install I would sure think your belt is slipping. I put about 2600 miles on my n/a nytro belt before she blew going across a lake in deep snow.

 

[sideshowBob]

With a used sled, especially a modified sled, never assume the P.O. set the sled up or maintained the sled to any kind of standard.
Clean and check your clutches, rollers, bushings weights, secondary buttons ect
Check your clutch alignment
Clean your chaincase, check bearings, adjust chain ect
Check both your Jackshaft and drive shaft bearings
That MPI Nytro should have destroyed a stock Nytro
Once you ensure the sled is sound maintenance wise you could start to dial in the clutch settings
JM.02c

 

[YammieDave]

No truer statement has ever been said on assuming the PO did it right. I have been going through a number of things to get them up to my standards, so clutching will have to be on that list. I did check alignment as that was my first suspicion, but that looks good.