HELP!! 1994 KX500 motor noises

[reklessj]

I recently bought my first 500 and she runs great (better have a good grip when you twist that right wrist).  One thing that bothers me after seeing that sik AF with its guts all over the place is a cross between a knock and a ping sound when I get OFF the throttle most noticeable when standing in attack mode.  Everyone on here is great and Ive already learned alot hoping you guys can give some insight!! Thanks!!

[greencannon]

first off dont compare it to anythng else. the 5 is a whole different animal.
 without riding it for myself and assuming best case scenario, sounds to me like  the normal K5 ping mixed in with a little kips powervale "knock" 
see if you can find another 500 owner localy for an educated opinion on yours

[dmazz71]

I'm a new owner of a 500 (03) too and seemed to notice the ping and knocking noise when I ran 93 octane gas in it. I haven't notices anymore noises since I switched to race gas (VP c12 or Sunoco GT100).  Not sure if it was a coincidence, but I'm going to stick with running the race gas anyway.

[reklessj]

Thanks guys!! Dont really know anyone in my area its just me and my wife and miles and miles of border road and trails.  I checked out the KIPS fine tuning topic and think I will tinker with that a bit and pick me up some race fuel next time I'm in town. Hopefully I'll be able to go tear it up wiyhout the fear of blowin'er up!! If you guys are ever out in San Diego's East County hit me up, me and my wife can show ya some pretty cool spots!  THANKS AGAIN

[Motorrad]

Thanks guys!! Dont really know anyone in my area its just me and my wife and miles and miles of border road and trails.  I checked out the KIPS fine tuning topic and think I will tinker with that a bit and pick me up some race fuel next time I'm in town. Hopefully I'll be able to go tear it up wiyhout the fear of blowin'er up!! If you guys are ever out in San Diego's East County hit me up, me and my wife can show ya some pretty cool spots!  THANKS AGAIN

see if you can find another 500 owner localy for an educated opinion on yours

He is in luck..

You my friend are local to me if your in San Diego...

Always willing to help out a fellow K5 owner

Im down in chula vista... for now (looking to move out to the STICKS... far east end of jamul)

[Polar-Bus]

A common issue with the "big 5" is the exhaust head pipe vibrating against the inside cylinder. I run a double exhaust gasket. And make sure the pipe o rings are in good condition. If not the vibration causes the exhaust flange to hammer the crap out of the inside of the cylinder.

[ToomanyKaws]

I have a wiseco in my one 500.   And my other 500 is still the OEM piston.   Both bikes don't like 91 octane out here.     I mix in 50% 100 and both engines are quiet.   I run straight 100 and they both haul ass.    People say oh that much octane is a waste.  Not needed.   Sure seems to make a difference.     And I tried to jet to alleviate any pinging on 91 to no avail.   Had the needle all over the place.   

My main point is on 91, you would think either engine was going to grenade on decel and at various rpm and load ranges.   And yes the 500 has its own noises compared to about any other two stroke I have had.     Amazing what some octane does to make an engine happy.

[kwakman]

next time you,ve got the stator cover off, try and pull the flywheel up and down.if you get any discernable play, your bearings need attention.i would advise any new/prospective 5 owner to check this when buying, or in your case,as soon as its viable. this is unlikely to cause the noises you speak of, but theres a lot of inertia and other forces which will make an expensive mess of your new baby.protect your investment and check it before winding her out...

[awak100]

Race gas?  Did you up the compression quite a bit?  I see guys running race gas all the time at hill climbs.  Dam bikes spit sputer fart.  Lets see up compression up up gas,  stock compression stock gas 92 Save alot of money that way