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sbohanon

gear noise, lower right side

7 posts in this topic

i have lower right side noise similar to a loud cam chain. checked out roostns' post about similar noise and decided to check it out per hicks routine. after removing the side cover, found no apparent play in the cb drive gear. bike is a '99 yz400 with about 500-700 miles. before the noise got louder, the (3) previous rides were very tight eastern woods. rode very fast with a lot of clutch. the clutch also seemed to get harder to disengage as the day went. each time we stopped, the clutch was easy again for about 20 minutes, then it got very hard again. since we rode for about 2 hours before the clutch got harder, and it was cold out, it could be that my fingers got tired. the unusual thing though, was if my fingers were tired they would normally be sore for a few days later. not this time. what could possibly make the clutch harder to disengage? also what could still be causing the cam chain type noise? or is it just due to milelage?

any thoughts appreciated.

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I haven’t heard of any ‘99s having the straight key/CB drive gear problem. For some reason that seems to be an ’00 thing only.

The only thing I can think of that would make your clutch stiffer is perhaps the basket is beginning to get grooved and it is getting harder to push the plates out of these grooves when you disengage the clutch.

As for the noise it could be normal, it’s hard to say from here. My ’00 is in perfect mech. condition and it still makes a lot of racket.

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Originally posted by Hick:

I haven’t heard of any ‘99s having the straight key/CB drive gear problem. For some reason that seems to be an ’00 thing only.

The only thing I can think of that would make your clutch stiffer is perhaps the basket is beginning to get grooved and it is getting harder to push the plates out of these grooves when you disengage the clutch.

As for the noise it could be normal, it’s hard to say from here. My ’00 is in perfect mech. condition and it still makes a lot of racket.

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Hi guys! I also purchased a used '99 YZ400 and the motor does make a racket! ( timing chain type noise ) The local dealer here says it may be a worn out of spec. piston, but bike has tons of compression and does not smoke at all, was very well maintained by previous owner and ran 20W50. After reading Hick's many posts I thought it would be wise to do the procedure he recommended. However does this apply to the '99 bike , due to a different kind of keyway config?

Am looking forward to a tear down on my holiday break. By the way, love this site!

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[This message has been edited by Hugh LePage (edited 12-18-2000).]

[This message has been edited by Hugh LePage (edited 12-18-2000).]

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Originally posted by Hugh LePage:

However does this apply to the '99 bike , due to a different kind of keyway config?

I dunno Hugh, the actual key itself is a different PN from ’99 to ’00 and I believe they changed the crank (and rod) from ’99 to ’00, but the drive gear is the same. I’ve only heard of this problem in ’00 models and never did figure out why this happened to my bike.

I suspect that probably 80% of the people who think they have a strange noise are just hearing ordinary DOHC thumper noises. My bike runs great now and makes a pretty fair amount of mechanical racket.

I hope I haven’t created some sort of paranoia (I’m picturing hundreds of misguided YZF owners yanking side covers and wiggling counterbalancers) but this has been a problem that several other visitors here have documented, but, as far as I know, always on ’00 models.

But I suppose it don’t hurt nothin’ to check…

[This message has been edited by Hick (edited 12-19-2000).]

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Thanks for the reply Hick! In retrospect the reason I find my bike noisy is that I am comparing it to a showroom '01 426 that the dealer lit up for me before I decided on a used bike. However, I will fine-tooth comb it just to make sure. I'll also check out the timing chain tensioner and the valve train specs. Depending how much time I have over the winter I may even pull the top end and have a look around in there as well as mesuring everything in sight ( I'm a perfectionist ) Don't worry about misleading anyone Hick, your informed suggestions are well appreciated! :)

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i quess being paranoid is normal when your talking about a hi-revving bike that i would not want to have explode 20 miles from anywhere. anyway, when i took my bike apart, everything looks good. so i will assume the noise is normal thumper racket. while its apart im going to replace the clutch. thanks for the replies.

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