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Pinging like knocking noise!
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Posted by:

OK.....maybe its just me, but it seems like the top end of my R is knocking like crazy! I just picked up this R and it has the CT 330 kit on it.

Is the knocking noise normal on the R's? I am new to actually owning a 2-stroke, but have been around them for years. I have always owned a 4-stroke until now!

Posted by: Blown 331

It's hard to say with out hearing it. 2-strokes are normally a little noisey. Being you have a big bore I bet they have a high compression piston and you may be hearing spark knock. Try some 110 octane and see if it goes away. It could also just be a worn out motor and you are hearing piston slap.

Posted by: RUNMYTA

If you are hearing a "knocking" sound up high on the jug you can just about bet that it is a lose bore and needs to be rebuilt. It sounds like a tap, tap, tap, and increases with higher revs.

Posted by: exrider360

its gonna blow that what we heard in my freind 310r whne were going back to the house but by the time we got back it was gone.

Posted by: ESR350r

Some noise is expected like the otheres have said. what octane of gas are you running? with that 330 kit you should definetly be running 110+ octane race gas

Posted by: exrider360

what should you be runnig with a ct 310 kit

Posted by: ESR350r

That depends on your compression. I ran preimium in my stock motor.... i would run 104 or 110 if i was youdepending on compression. You cannot run too high of an octane in your motor, running too low will cause it to knock because 2 flame fronts will meet when the fuel combusts. You can increase the life of your motor and get a little performance out of higher octane. the only thing it will hurt is your wallet.

Posted by:

I'm running VP C12 which is 108 octane. I rode it all last weekend and it ran good. I think I might have over reacted with the noise a little bit. I'm not used to the R yet. I talked with some other people and the previous owner and they said that i'm ok (they listened to it run).

Thanks for the info guys!

Posted by: skidaddyjr

If you just bought take the cylinder off and check the piston,rod + wrist pin bearing. base gaskets are cheap! bore it and replace the piston if you are unsure.Pro Cross are high maintnace and require close attention to piston wall clearances. Its not pretty when they go boom!Also check the counterbalancer bearings for play.Just trying to save a headache over buying christmas or new motor.

Posted by: BeeeRock!

R's have a KNOCKING sound it drive me nuts, but they have that sound