need more rpms

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RockinJW

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My mountain light only spins about 10,600-10-700 rpms at wide open throttle. I'm new to the Yamaha clutch set-ups, can anyone tell me how to change that so I can bring the rpms up?

On my Cats I just had to tighten the driven spring, but these Yammi clutches are a little different...
 
gabe7924 said:
How many miles on your sled? Mine didnt hit high rpm(113000-115000) until after about 80 miles.
Click to expand...

That's a lot of RPM! :tg:
 
This motor makes prime power at 11300-11500. Yours should hit that high at wide open throttle. It could have something to do with your homemade exhaust. You may not have enough back pressure. I bet if you put your stock exhaust back on, you will hit the right RPM. There is something to be said for spending money on the right exhaust.
 
gabe7924 said:
It could have something to do with your homemade exhaust. You may not have enough back pressure. I bet if you put your stock exhaust back on, you will hit the right RPM. There is something to be said for spending money on the right exhaust.
Click to expand...

I would bet its your exhaust as well. Put your stock one on and see if that fixes it.
 
Well, i don't want to put the stock exhaust back on, I'd really like to just clutch it to work with what I got.
 
This sled off of the showroom floor with stock clutching kicks butt. Why wouldnt you at least test your stock pipe to see if it is your exhaust causing the problem? If you want to change your clutching just so you can use your home made pipe, knock yourself out. Let me know how it works out for you.
 
If you change your clutching to match your pipe, more than likely you'll lose bottom end..
but more than likely you probably need a bit more backpressure
to get the most out of your exhaust.. to test see if you can get a reducing tip for the very end of your pipe, you might be able to see a difference.
 
You can tighten up the secondary... Take it off, remove the snap ring and follow this chart.

Why not just put 3 engagement shims in the primary... Thats what I would try first.

About the whole pipe thing, well, I've never seen any instant where a person has installed a perforated core straight through muffler and LOST power compared to a restrictive stock unit... Doesn't make sense. You should pickup bottom end, all the way through the top end. May be wrong though, maybe this engine is different from all the others in the world. You don't see John Force running a stock muffler on his funnycar... :Rockon:
 

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I'm almost sure my sled ddidn't lose any power with the exhaust I built. I was riding with a Yammi dealer this past weak and could outrun there box stock phazer mtn. light pretty easily.

Also, the 11lbs I lost by going to this homwmade kit is worth something, even if it lost 1-2hp, which I dont think it did.

Thanks for that info Mars, that's what I was looking for.
 
Bottom line is this: if your motor is not getting to at least 11300 RPM, you are not making peak power. Do whatever you want with it and have fun.
 
That's why I'd like to ind the clutches a little tighter, so I can get up to the 11,300 range
 
Has anyone got a dynograph of this engine? if so, can you e-mail it to me.

Just wanna see if the power drops off after 11300, Id imagine there is a rev limiter somewhere built into the computer anyways.
 
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