Hitting rev limiter?

[Woody255]

Hello all, first post in some time here. Somewhat of a unique situation I think. A friend has a 2020 SW XTX. All stock except the Hurricane/Hindle Mountain Lite can. A few days ago the sled blew a belt while under heavy load. The belt disintegrated, and a piece of cord wrapped up in behind the primary onto the stub shaft. We were unable to remove it trail side. He rode 25 miles back to my shop. We pulled the primary off, which was the most difficult one to remove I’ve encountered yet.

Once the clutch was removed, we could see the bearing on the stub needed to be recessed. This was completed in a press.

A new 8JP belt installed, no other issues observed. On the next ride, the sled appears to be hitting the rev limited. 9350 was seen on the tach. No changes were made, and no evidence of belt slipping. Clutches are clean.

Anyone experience this? Thanks.

 

[0degC]

Hello all, first post in some time here. Somewhat of a unique situation I think. A friend has a 2020 SW XTX. All stock except the Hurricane/Hindle Mountain Lite can. A few days ago the sled blew a belt while under heavy load. The belt disintegrated, and a piece of cord wrapped up in behind the primary onto the stub shaft. We were unable to remove it trail side. He rode 25 miles back to my shop. We pulled the primary off, which was the most difficult one to remove I’ve encountered yet.

Once the clutch was removed, we could see the bearing on the stub needed to be recessed. This was completed in a press.

A new 8JP belt installed, no other issues observed. On the next ride, the sled appears to be hitting the rev limited. 9350 was seen on the tach. No changes were made, and no evidence of belt slipping. Clutches are clean.

Anyone experience this? Thanks.

you could be overrevving or over boosting with the can not having a tune. odd it did not do before the belt change but guess the new belt and maybe better clutch alignment is working better getting you into cutback?
I think that muffler is suppose to give you 15hp so add some weight to primary or you could go to an XS belt to bring down your rpm.. if that is your problem.

 

[KnappAttack]

Hello all, first post in some time here. Somewhat of a unique situation I think. A friend has a 2020 SW XTX. All stock except the Hurricane/Hindle Mountain Lite can. A few days ago the sled blew a belt while under heavy load. The belt disintegrated, and a piece of cord wrapped up in behind the primary onto the stub shaft. We were unable to remove it trail side. He rode 25 miles back to my shop. We pulled the primary off, which was the most difficult one to remove I’ve encountered yet.

Once the clutch was removed, we could see the bearing on the stub needed to be recessed. This was completed in a press.

A new 8JP belt installed, no other issues observed. On the next ride, the sled appears to be hitting the rev limited. 9350 was seen on the tach. No changes were made, and no evidence of belt slipping. Clutches are clean.

Anyone experience this? Thanks.

I'm not sure where the rev limit is on a stocker, but I'm pretty sure its higher than that, 9500 I think. I'm guessing the belt change is allowing an overboost situation with the the aftermarket muffler on called a boost cut. It could be allowing it to RPM quicker or less quick. The boost cut shuts down just like a rev limiter does, but not RPM related. Its boost activated. The muffler puts the boost higher and into the boost cut without a tune to raise the boost cut up. The muffler is putting it right on the edge and the new belt has changed it just that little bit. The machine should have a free flowing muffler tune installed to cure it really.

 

[DennyTuna]

I agree with both Knapp and OdegC, a buddy of mine put an aftermarket muffler on his stock Thundercat, nothing but over revving and backfiring was the result. That was his attempt to close the gap on my 240 tune....did not work out well for him.

 

[Turboflash]

I agree with everyone too. I also would NOT put a muffler like that on a stock tune. It's has to be really lean!

 

[Srxspec]

I'm not sure where the rev limit is on a stocker, but I'm pretty sure its higher than that, 9500 I think. I'm guessing the belt change is allowing an overboost situation with the the aftermarket muffler on called a boost cut. It could be allowing it to RPM quicker or less quick. The boost cut shuts down just like a rev limiter does, but not RPM related. Its boost activated. The muffler puts the boost higher and into the boost cut without a tune to raise the boost cut up. The muffler is putting it right on the edge and the new belt has changed it just that little bit. The machine should have a free flowing muffler tune installed to cure it really.

Stock rev limiter is 9400 rpm.

 

[KnappAttack]

Stock rev limiter is 9400 rpm.

Thanks Allen.

So if its indeed just hitting the rev limiter, adding with to the primary, feeding it more helix or swapping to an Ultimax XS belt should fix that easy enough to keep it off the rev limit. If it still shutting down then it's the boost cut making it act up.