Grinding Noisy Sound and Occasional Squealing

[TriniG]

I have a 1998 KDX220. As of recent, I have found that the engine noise has increased dramatically. Eg At 50Kmph I can hear this grinding, pulsating noise. When I stop and increase the revs, its the same grinding lound noise. Not typical of a Piston slap, though I know I'm due for a fresh top end. Then out of the blue I started hearing a squealing noise while in neutral (coupled with the other noise) you could see when I reved that the chin would tension like it wanted to move forward. The squealing disappeared as soon as I pulled in the clutch lever. This was an intermitent problem. The next day it did not squeal. But I suspect there maybe some clutch problem looming ahead. Has anyone experienced this and solved it?
The grinding noise is ever-present. None of this has affected the power of the bike. But I don't want to break it. Anyone experienced this? Could it be a bad bearing. I'm not sure where to start looking. I'm going to have to tear down the engine, but don't want to do more than I have to in order to get to the bottom of this.

Any suggestions appreciated.

 

[MX Junkie]

Take a look at your clucth basket, the fingers are more than likely worn (grooved) and/or the gear came loose off the basket.

 

[canyncarvr]

You might want to take a look at your topend sooner than later. Are you using an OEM piston?

If you haven't serviced the clutch...at eight years old, with any riding, the basket is likely in pretty rough shape.

 

[TriniG]

I replaced the clutch plate with EBC plates in June 2004 (at the time, the basket looked perfect) and put in a Standard 69mm Wiseco piston kit in November 2004. I'm going to take apart the top end and take some tolerance measurements. My 220 has about 5,000 km on the clock.

I noticed on the bike bandit site that you can get the standard Wiseco 69mm and two Wiseco oversize, 69.5mm and 70mm.I was under the impression that the KDX cylinders are not reboreable. So my question is under what conditions does one use an oversize piston in a KDX.

I have a friend that resleeved his old KDX, a piece of engineering there. Now he can rebore.

 

[TriniG]

Solved the mystery of a Noisy Engine

Well finally got my parts to do a partial top end job. I've changed the rings, cleaned up the KIPS, left side valve was a little stuck. But the horrible noise I was getting I just figured out. Last time I changed oil, I put in 1 litre of Belray Hypoid gear oil 90w. To my horror, when I drained the engine I only got about 1/3 of a litre out. Where did the reast go? The oil was a mixture of the Belray Red, and also a sludge-like black. Now metal filings, no water. I then decided to open up the clutch side to have a quick look at the clutch basket. It had very little signs of wear. Theoretically, when I start up next, the engine should be decidedly quieter.

Shaun