Weird Noise 2001 KX500

[AV8]

I just bought this KX and I am worried I may have jumped too quick. It has tons of compression, starts and idles great but has a strange kinda loud noise above idle that I cannot figure out.  It sougnded like the pipe was hitting the frame and vibrating, my mechanic and friends said the same thing. I took a piece of wood and pushed on the pipe to stabilize it at different points and that didn't help.  I shut down and bumped the pipe with my palm to see if something may be loose inside the pipe and nothing. I cannot find anything loose on the engine or frame. I have not had the pipe off, but  I wonder if the o rings on my Gnarley are gone causing this noise. All the springs on the pipe look good and are all there.  This really has me worried, although it does not sound like a knock. What could the noise be?

Any help is appreciated

Phil

[AV8]

The only thing I could find on the site is trying a copper washer at the pipe mount to the cyl. Where does one find a cooper washer?

Phil

[Hillclimb#42]

Its an exhaust bushing that is supposed to be in there. The copper ring lets the pipe wear on it, instead of wearing out the cylinder. My 500 likes to loosen the subframe bolts. The allens that are close to the swing arm. Many have a crank out of balance, including mine. Other things to check are the kick starter rubbing the pipe, brake pedal on case, exhaust springs laying on the pipe, head stay, radiator mounts, rubber bushing between pipe and silencer. (It goes through the sub-frame.
  You are probably on the right track with the copper washer and definately get new o-rings. Any leakage there is like drilling a hole in the side of the pipe. A good look at the pipe where it goes into the head will tell you what it is doing. Any leak will show up black and wear will be polished clean.

[AV8]

Hillclimb,

I will pull the pipe this morning and with luck, find the culprit.

Thanks

[jfabmotorsports.com]

While you are at it pull the mag cover and see if there is any play in the crank. Unfound noise can offen be a bad crank or rod bearing. Rod bearing is a little harder to check.

[AV8]

While you are at it pull the mag cover and see if there is any play in the crank. Unfound noise can offen be a bad crank or rod bearing. Rod bearing is a little harder to check.

I did the old handle of a screwdriver to the ear and the hard end to the case in different places and didn't hear anything unusual.  I will pull the cover today and test for wear on the mains. I am starting to wish I had lots of money....and buy new. But, there would be no challenges in that.

[jfabmotorsports.com]

While you are at it pull the mag cover and see if there is any play in the crank. Unfound noise can offen be a bad crank or r

od bearing. Rod bearing is a little harder to check.

I did the old handle of a screwdriver to the ear and the hard end to the case in different places and didn't hear anything unusual.  I will pull the cover today and test for wear on the mains. I am starting to wish I had lots of money....and buy new. But, there would be no challenges in that.

Unless you are talking about buying a NEW screwdriver there would be a real big chalenge for you to buy a NEW K5, bike or engine!

[AV8]

Unless you are talking about buying a NEW screwdriver there would be a real big chalenge for you to buy a NEW K5, bike or engine!
[/quote]


I will have to stick with the screwdriver for today.. With a more powerful kick leg and a bailout from our treasure, maybe the ATK 700 Intimidator?

[500freak]

if its a metal rattling noise it might be piston slap. i have a dt 400 that had a rattle. it sounded like someone was tapping the jug with a hammer lightly. i rode it all summer like that, then i rebuilt it and found that was the noise.

[martinfan30]

Mine has a sort of light knocking sound too. Every KX5 I've heard has the same noise.

[toomany]

Mine has a sort of light knocking sound too. Every KX5 I've heard has the same noise.

I was told it's the powervalve govenor. Mine make a diesel sound as well as most every one I've heard. I just had the crank rebuilt and new bearings throughout the bottom end, so I know it's not that. The pistion is new, along with the bore...so it's not piston slap on mine.