Low RPMs with Ultimax Belt

[concretepaul]

I have recently switched to an Ultimax XS805 belt on my 09 Nytro XTX. I have 18/39 gearing and the backcountry 1.75 track. I was able to get 8750 rpm going down the road with the 8DN belt, now I am only able to get 8300. The XS805 appears to be slightly longer than the 8DN. Has anybody else seen this and/or have a fix. The belt is riding just barely out of the secondary.

Thanks,

Paul

 

[dirkdiggler]

The Dayco belts are softer. Your actually grabbing your belt better then you do with the 8dn that's why your rpms are down.

 

[nytro addict]

The Dayco belts are softer. Your actually grabbing your belt better then you do with the 8dn that's why your rpms are down.

X2

 

[stephenpen]

I'm going through the same thing right now. On my yamaha belt I revved around 9000rpm and now I rev at 86-8700 with the XS 805 belt. I was not sure If it was the belt because I changed my muffler and fuel controller all at the same time. I decided to go back to the Yami belt. Hopefully my revs with come back. I let you know how its goes later this weekend.

 

[NFLD-Nytro]

The Nytro is the first sled I've had in years that I have NO idea where it's reving or shifting. I've often thought about putting the gages from a Vector on the Nytro, so I could actually see what was going on, but don't like the price.
Anyway, as I get older I get less concerned about those things, as long as the sled is working good, and goes where I want it to go, I'm happy.

 

[mach9]

With stock clutching I ran an XS805 to some very nice top speeds.
But when I switched to heavier weights to grab the belt harder it blew fast.
I'm running the Yammie 8DN now with heavier weights without problems.

 

[concretepaul]

Thanks for the help. I think I am going to go back to the 8DN for simplicity sake.

 

[mcamzr]

I have had the flip result on 3 sleds now (121 models though) on my ZR, MXZX and Now the Nytro I saw a 200 RPM Gain with the Ultimax XS vs the OEM. On the Nytro it was a bit longer but mic'ed the same on the width so I shimmed the secondary to get the right deflection, the XS is a much softer belt so it does grab better but I put 100 miles on the OEM belt and switched to the XS and it seemed to cure a tiny flat spot in the accelaration around 7500 (ish since you cant really tell with the Nytro guage). So now I wonder why I saw an increse in RPM when everyone say a decrese? could it be my sleds were all 121?