Clutch weights or just a different belt?

[TheFarm845]

I scored a nearly-new BMP full velocity muffler for my 22 LTX. BMP said they recommend their clutch kit to bring the rpms back down due to the muffler. However, I just came across a post from a couple years ago while searching other things and someone mentioned that the Ultimax XS825 will bring your rpms down by 400-500 because it won't slip like the stock belt. Soooo is that true? Seems like a lot. And if so, can a guy just run that belt instead of buying weights and springs?

 

[snowdust]

I'd say more like a drop of 3-400 but yes you can just run that belt to drop the RPM.

 

[DMCTurbo]

Do you have a tune?

 

[TheFarm845]

Do you have a tune?

Nope

 

[DMCTurbo]

Nope

A high flow muffler is going to cause the engine to run lean. Most aftermarket mufflers will require a tune. You best speak to BMP. I'm not familiar with that exhaust.

 

[WinderFab]

20-25 hp increase with no tune required?

Arctic Cat 9000 / Yamaha Sidewinder - Full Velocity Exhaust (2017+)

Fits 2017-Up Arctic Cat 9000 & Yamaha Sidewinder Models A HUGE 20-25 HP Gain No fuel or tuning changes required Our Stage 2 clutch kit is highly recommended A must-have for any sled with tuning Weighs only 10 lbs. Great fit and finish Available in bare stainless or ceramic chrome Need a...

bikemanperformance.com

 

[TheFarm845]

A high flow muffler is going to cause the engine to run lean. Most aftermarket mufflers will require a tune. You best speak to BMP. I'm not familiar with that exhaust.

Bikeman Performance. I called them and they assured me I won't need a tune, its a 2.5" trail muffler. Just highly recommended to clutch it to pull rpms back down. They make tons of products for 2 stroke sleds

 

[TheFarm845]

20-25 hp increase with no tune required?

Arctic Cat 9000 / Yamaha Sidewinder - Full Velocity Exhaust (2017+)

Fits 2017-Up Arctic Cat 9000 & Yamaha Sidewinder Models A HUGE 20-25 HP Gain No fuel or tuning changes required Our Stage 2 clutch kit is highly recommended A must-have for any sled with tuning Weighs only 10 lbs. Great fit and finish Available in bare stainless or ceramic chrome Need a...

bikemanperformance.com

Apparently. That's what they showed on their dyno. That was on a first year 998 thundercat.

 

[DMCTurbo]

Bikeman Performance. I called them and they assured me I won't need a tune, its a 2.5" trail muffler. Just highly recommended to clutch it to pull rpms back down. They make tons of products for 2 stroke sleds

My 6 years experience with these sleds tells me otherwise.

 

[justinator]

Their dyno inflates their products performance far greater than you will ever see if compared on someone elses dyno. They are well known for their overly optimistic dyno. If it in fact runs without a tune im guessing its less than 10hp. For less than the price of that muffler you can buy an 230hp ecotrail stock muffler tune or a 225 stock muffler tune from hurricane and get way more power……safely.

 

[TheFarm845]

I bought it mainly for a little more sound. I have a 4 year warranty so I don't plan on a tune. I honestly could care less if the gain is only 2hp haha. I only paid $275 for it with less than 100 miles of use on it so it was hard to pass it up

 

[jonlafon1]

The XS 825 belt will probably pull your rpm down real nice with that muffler. I would definitely try that first. Otherwise if it doesn’t work go with a adjustable weight from thunder, Dalton or DD.

 

[TheFarm845]

The XS 825 belt will probably pull your rpm down real nice with that muffler. I would definitely try that first. Otherwise if it doesn’t work go with a adjustable weight from thunder, Dalton or DD.

Perfect, because I already bought a XS825 as a spare, so I'll just swap it out before riding next season!

 

[number1kyster]

As others have said, you should have a tune with that muffler. I think Bikeman is giving you bad advice unless the muffler they sold you flows close to stock levels.

The XS825 will bring your RPMs down. No need for clutch weights.

 

[Motorhead]

Start by just adding the muffler and nothing else.
If it over revs, it’s doing something. If not, you need nothing more!
8750 is stock revs, but I always have preferred 8850.

Does Bikeman give a target rpm for their No Tune exhaust?