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Procircuit or FMF
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Posted by: Raptor350yamaha

Which would be a better exhaust for trail riding only. The Hot Seat Perf. has good top end but bottom end is I think worse than stock. Procircuit and FMF

Posted by: Jersey450R

neither. try HMF or sparks.

Posted by: bigdaddy

Get a Hetrick pipe. IMO it is the best. We had a Hotseat pipe and had nothing but problems with it. You will have to rejet and should do your clutch. They can set you up with what you need.

Posted by: Raptor350yamaha

to exspensive for me im just a 14 year old

Posted by: LT80

Trinity.

Posted by: Spike99

.

For the longest time, I was a firm believer in the FMF pipe for trail riders - for the Pred-90 brand. From a white board perspective, it seemed to be a great low cost pipe for releasing bottom end power. But after a while, I noticed lots of complaints about this specific pipe. People where having problems with their FMF pipe and FMF Corporation wasn't giving them an easy process for returns / replacements.

When all was said and done and "emotions are taken out of their posts", many people have stated the FMF pipe and mini's carb must be "perfectly tuned". And the FMF Pipe's packing must be checked / re-done after 10 hours of riding. If the entire configuration isn't 100%, this pipe WILL run too hot. It melts down and it could / can create long term engine problems.

If you do run the FMF Pipe, do ensure the mini's spark plug is "always" beer bottle brown (2 stroke engines) and the FMF's stuffing is checked after 10 hours of riding. If you don't do this, one could have a melted FMF pipe as well.

Note: One bad post is fluke, 2 bad posts get my attention and many bad posts show a pattern. To me, the many FMF posts on other forums show a clear pattern of its history (when installed on the Pred-90s).

Hope this helps in your decision....

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Posted by: Samson

quote:
Originally posted by LT80
Trinity.

Hetrick and Trinity look the same to me????

WRH is right there with them too. You'll get more support from Hetrick or WRH though.

Tell your Pa to pull that wallet out!

Posted by: 400ex4ever

Another option is Eastside Motorsports .

Posted by: Raptor350yamaha

are those pipes good for trail riding or top speed situations. i need tons of low end from an exhaust

Posted by: 400ex4ever

With any pipe you can adjust the top or low end speed with the Torsion spring (?) behind the clutch itself. The one I am using is a 2000 rpm stall (RED) plus the variator weights are 5.4 grams for a lot of top speed. I would call Hetrick or WRH and let them know what type of riding you do. They will have the answer.

Posted by: LT80

Samson, surely you know the pipe story

These pipes are indeed made for low end (as opposed to a pipe like the technigas that produces 2500 more rpm). They have a great power delivery thru the rpm range tho.

I don't understand 400exforevers reply stating that you can change the pipe charicteristics with the torsion spring. The torsion spring slows the opening of the rear clutch pulley faces and only has a small amount to do with the stall speed. The majority of the stall speed adjustment comes from roller weight/rear clutch shoe weight and the springs that go on the shoes. Motor rpms will be the same no matter what torsion spring is used. Now if you under weight the rollers and do not get full clutch travel, then speed would be effected.

Posted by: 400ex4ever

quote:
Originally posted by LT80
Samson, surely you know the pipe story

These pipes are indeed made for low end (as opposed to a pipe like the technigas that produces 2500 more rpm). They have a great power delivery thru the rpm range tho.

I don't understand 400exforevers reply stating that you can change the pipe charicteristics with the torsion spring. The torsion spring slows the opening of the rear clutch pulley faces and only has a small amount to do with the stall speed. The majority of the stall speed adjustment comes from roller weight/rear clutch shoe weight and the springs that go on the shoes. Motor rpms will be the same no matter what torsion spring is used. Now if you under weight the rollers and do not get full clutch travel, then speed would be effected.

I am still learning this CVT thing but what you said makes more sence. Just trying to help with what little knowledge I got....

Posted by: Samson

quote:
Originally posted by LT80
Samson, surely you know the pipe story

Well, been around long enough to hear the accusations. Just didn't know how much stock to put in it or if the pipes have been tweeked.

Posted by: Evana13

hot seat makes a great pipe but you will need to get a k&n tranny kit and the pipe. It makes it rip but you could also try a hetrick c kit I think is what its called here is the link www.hetrickracing.com

Posted by: AFROracing

w

Posted by: AFROracing

what type of main jets do the 90 predators take?

Posted by: 400ex4ever

I remeber them being a small round type. I switched carbs way back to a 28mm and they use the Keihen style.

Posted by: sldhd700

I recently removed an FMF from my son predator and replaced it with a Hotseat pipe. The FMF seemed to have a ton of bottom end it wasn t what I was looking for on the track. Although trail riding it worked great. I am wanting to sell the FMF pipe if your interested email me. This could save you alot of money.
sldhd700@aol.com