[nasty engine noise] - ATV Riders Forums - Honda, Yamaha, Suzuki, Kawasaki, Polaris, CanAm, Arctic Cat, Kymco ATVs

Pages:1

nasty engine noise
(Click here to view the original thread with full colors/images)

Posted by: dudleydoright15

started hearing a loud knock only when I let it idle then pop the throttle, also when I am in 4th and 5th gear about 3/4 throttle the same noise but like a rattle. I have a curtis sparks header and pipe.

No jet kit or intake

need some help with this situation.

Posted by: RaptorRacrr04

could b wrist pin needle bearings r gone

Posted by: Billdog350

Check for low oil, loose motor mounts, and loose bolts before assuming its anything internal. Once you know nothing is broken or loose outside, then think internals. I know my 2002 Mojave 250 knocked like crazy when it was under a load (lugging it) but everyone said it was normal for those machines. It still scared me though. The Suzuki/Kawi seems to be a more updated version of the old twin cam Mojave 250 motor. If so, that knock (piston slap maybe?) might be ok. I know the higher compression on the Mojave was supposed to be part of the reason why it made so much noise. Regardless, check compression next. Unless you are dead set on ripping it apart...you might be better off doing some inexpensive testing first.

Posted by: zowdy

sounds like your cam chain maybe stretched & no more auto- adjust left on the tensioner.

Posted by: zowdy

what you are hearing is the loose chain at idle slapping around. when you rev it inertia makes the chain balance and the slack is equal around the chain in the motor.def need to get it checked,if it jumps a tooth,lots of problems.

Posted by: yoshimurakfx400

it might be the valves, but you need to jet it