OK, here's one that's got me thinking!

My XT600E has started making a strange noise while running. It's a kind of slightly metallic sha-sha-sha sound (sorry for the crap description), similar to when you are passing regularly-spaced trees and the sound of the bike is reflected back at you. The sound is not unlike a loose washer vibrating. Fairly quiet, but just audible over the engine/exhaust at 40-60 mph. That's the best I can do! The puzzle is the frequency. At 40 mph, it happens at approximately 4 to the second, and varies with the bike's road speed. It is there with the clutch in and the engine dead, and carries on getting slower and slower until the bike stops. It's obviously chassis rather than engine.

The frequency is the puzzle. My maths (which could well be as rubbish as my descriptions) says that the wheels are turning at 8 (front) or 9 (rear) revolutions per second, which kind of rules them out, unless some strange feature is making the noise happen every second revolution.

My only answer is the chain, which at ~100 links with a 45T sprocket will make a full revolution at approximately half the rear wheel speed, or about 4 per second at 40. Does this make any sense at all?

It's n ot a big problem (yet) but I would like to put it right before it gets worse and starts wearing something important. Any comments or suggestions welcome. I should add that I have checked the bike over and nothing is obviously loose or rubbing.

Many thanks.

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

If it sounds like a loose washer vibrating it may be some kind of a resonance related thing, try to locate the sound when you ride and touch stuff, like the mirrors, speedo, tank, plastics and so on.. if the sound goes away you have found what is causing the noise.
More ideas.. Is your chain worn or loose? Chain slap? Is your chain slide (on the fork) worn through, do you have metal to metal contact when the chain slaps the fork?

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Yamaha XT600E '01, Honda XR400 '03, Yamaha XT550 '83

Resonance was my first thought, and I have done everything you mentioned - nothing loose or vibrating at all. And a loose mirror wouldn't vibrate at this frequency either, would have thought. I've had the tank, seat and tailpiece off to check for loose things - nothing.

I'm now 100% convinced it's the chain. I've checked everything over this morning - tension, chain line, the lot. No sounds while I was turning the wheel by hand, but when I got it on the paddock stand and let it idle in 1st, there was the noise again. I dribbled some Scottoil on the chain as it was turning, and the noise reduced quite a lot. Nothing seems to be touching that I can see, except the chain on the plastic slider (which it always has done without a rider on board). The only thing that has changed is the addition of a rear rack and small topbox.

It's possible that the extra weight and drag of the topbox have caused the suspension to compress more than before and the chain to rub on the lower slider (I am no lightweight and the preload was set fairly low) and that, combined with a dry chain (not lubed for 2-3 weeks) have caused the friction and the noise. I've lubed the chain and jacked the preload up to near maximum, and I will take it for a run this afternoon to see if that has fixed it. If it has, I'm suspecting a tight link in the chain, and I may well need a new one.

Thanks for the input, GS600.

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

It's the chain! also, check the chain rollers/sliders...when they are bad it makes that sound!


Vando

Hi Vando

Looks like you are right - I've just been out for a few miles and the noise has gone. The chain slider is pretty worn, so I suppose that should go on my shopping list too.

Cheers, and thanks to GS too.

Rich

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2006 XT660R daily ride, 1994 XT600E about to be reborn, Blog: http://goingfastgettingnowhere.blogspot.com/

Glad I could help!

The worn chain slider and rollers make the chain literally JUMP around and thus making that noise!

That noise was one of the things that made me want to get an enclosed chain guide for my XT...

I will however fabricate a strong engine case guard that fits between the engine case and the front sprocket to avoid any chain damage like those when the chain just jumps out of place and gets tangled up in the front...

This happened to me on my 2002 DT125R.. I was lucky tho, I could still manage to make a small incision on the engine cover for the clutch spring to gold on to...


Vando