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Discussion Starter · #1 ·
I know the 450 is not a speed demon but I thought it’s supposed to do around 35mph. I have 10,000 miles on this now and my am top speed is 24 mph on flat paved roads. This is with stock tires, no lift, everything else stock.

once it gets to top speed the rev limiter is kicking in above about 3/4 throttle.

this is what I have done so far.
New OEM belt (measures 28.5mm wide on top.)
New plug
New fuel filter
new air filter
Cleaned the connection under the air box for the green/white reverse wire.

Any thought?
 

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2006 660 Rhino
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I'd read up on a aftermarket CDI. I know the consensus is a airbox snorkel delete, and a slip on exhaust, CDI and enrich the carb jetting supposedly gets
you up to 40 ish.
 

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Discussion Starter · #3 ·
I'd read up on a aftermarket CDI. I know the consensus is a airbox snorkel delete, and a slip on exhaust, CDI and enrich the carb jetting supposedly gets
you up to 40 ish.
Do these cdi slowly go bad or is it all or nothing? The reason I ask is it will still hit the rev limiter just only goes 24mph. I thought they were supposed to go 35mph stock.
Could this be cdi related or is it more likely clutch related? When I pulled the old belt off both sheaves had about 1/4-3/8” of belt dust from the edge. Is the belt supposed to travel all the way to the edge or is this normal. Both sheaves are moving I just don’t know if they are moving far enough.
 

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2006 660 Rhino
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Clean up the sheaves. A lot of guys here talk about using 80 grit sand paper.
Gates says to use a scotch brite pad.

 

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07 686, msd cdi, twin-air filter, Tyrex shocks, stage 1 hot cam, lots of old school tuning tricks
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With the plastic belt cover off, fire up the engine and rev it up. Watch the belt on the rear pulley to make sure it moves all the way to the top. If the belt isn't moving all the way to the top, you need to service your sheave. The fact you're still hitting your rev limiter tells me there's nothing with the engine that has caused your reduction in top speed. An aftermarket cdi will help, but only if your sheave is working properly.
 

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Discussion Starter · #6 ·
With the plastic belt cover off, fire up the engine and rev it up. Watch the belt on the rear pulley to make sure it moves all the way to the top. If the belt isn't moving all the way to the top, you need to service your sheave. The fact you're still hitting your rev limiter tells me there's nothing with the engine that has caused your reduction in top speed. An aftermarket cdi will help, but only if your sheave is working properly.
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The first two pictures are with it off, second two are wide open bouncing off the rev limiter. It appears it is not riding up to the edge of the sheave with weights.
Am I better off buying a new one or pulling it apart clean/ replace parts?
 

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Since you have to disassemble no matter what, take it apart and see if you can get away with just a cleaning - you can always go the other route should you want to. It's pretty obvious you have an issue with the belt not riding all the way up - that's most likely all your lack of performance right there.
 

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Discussion Starter · #8 ·
Here it is taken apart, everything looks there but I don’t know what I’m looking for.

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Discussion Starter · #9 ·
I cleaned one of the weights up and it has a flat spot on it and some deep scratches in the outer circumference of it. I assume this is bad but is that what is cause the clutch not to slide correctly?
 

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Ya you definitely want to clean all that up. I picked up greaseless weights from hunter works as I had the same problem not hitting top speed. All that build up stops your weights from fully travelling. Look up the slug kit from them aswell. Helps on the bottom end .
 

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I cleaned one of the weights up and it has a flat spot on it and some deep scratches in the outer circumference of it. I assume this is bad but is that what is cause the clutch not to slide correctly?
this is what mine looked like before I cleaned it all up.Weights couldn’t do there job with all the carbon build up.
 

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Glad you got some good input here. I also went with Hunter Works using their dry Sheave unit. That was a couple of years ago (at least) and no problems so far..
 

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2006 660 Rhino
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Did you run through a lot of streams or puddles? Seems like more rust than I've seen before.
 

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Discussion Starter · #14 ·
Just wanted to follow up with a conclusion to this thread. I ordered a hot shot sheave kit with spring and all the parts came in. I replaced all of the seals and o rings as well. It will now do 39mph with 40 on a slight down hill. Thanks for all the help here. I think I have all of the big and little issues fixed now on it.
I think I will try and find or build a front rack for this rhino before hunting season and would like to change the tires out to either a 26” or 27” light mud tire
 
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