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'98 KLX300 Head Knocking?

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I was thinking of buying a beutiful 98 300, it ran OK and started easy but it sounded like a gremlin in the head with a Ball peen hammer! A very loud pecking noise seems to be in the head, maybe a litle louder on Cam chain side. Almost sounds like a rocker arm flapping. ( I know there isn't any. )

I eased in on the compression release but it didnt seem to matter and I dont think its too tight.

Bike would wheely only in 1st and 2nd, not on demand in third, bike may have been down on power but I cant tell as I have never rode one, only ridden my XR400. ( XR wheelies through 3rd easily )

bike has very strong compression when kicking kinda slow without compression release pulled in.

Owner said its always made that noise ever since he has owned it and has ridden it a little every year for the last several years without it getting any worse, But it don't sound right to me. Far from the sewing machine sound I'd expect.

Major? Minor? any thoughts?

Thanks for the info in advance.

signed, Afraid to Buy!

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I just did a total rebuild on an 03 klx300 to solve this very same noise.

After lots and lots of money was thrown at it the noise remained.It's a very loud head tap especially above idle. The fix actually required no money and 30 seconds to cure the noise.You losen the automatic chain tensioner just about 1/16 of an inch then tighten it back up. This will quiet it right down.Or replace the tensioner with a new one.Either way it's an easy fix.

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that is something that the klx300 has always done you will know when there is something wrong with the top end trust me i had it happen to me it is a scary noise. goodluck.

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Well I'm now the new owner, and have figured out the knock......

Timing chain slap. the tensioner is all the way in and still not enough.

Just to see, I fashioned a small piece of aluminun tubing that fit over and beyond the tensioner about 3/16" of an inch and bolted it back in,this gave me about 1/8" of push on the tensioner band inside and hushed it right up. Sounds like I'd expect one to. Now I know I need a Chain, but should I replace the cam and drive gears too? How about piston rings while I'm that far in? Any suggestions on best place to buy parts online?

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I'd definately replace that chain right away. The cheapest place I've found for OEM parts online - or anywhere for that matter - is the Thumpertalk OEM store. I don't think they have listings for Kawi parts, but I would call them anyway. I bet they can get it. I wouldn't bother with the cams unless they show signs of extreme wear. Rings wouldn't hurt, but at that point, why not put in a piston too? I'd just check the valves and put in the chain and go for it.

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Got the timing chain from the Thumpertalk OEM store. Beat everyone's price by at least $20.00, and shipped fast too. This fixed it right up and it now purrs like a kitten. Its a sweet ride in the woods and hills of east KY! I am thinking of purchasing the manual timing chain tensioner before I put to many miles on it though cause that OEM automatic job seemed a bit on the tight side to install. :mad:

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What do you mean tight to install? Did you remove the tension spring prior to install?

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I just went through this too. The chain didn't seem that stretched, The spring in the tensioner looked a little worn on the sides. I don't think the one-way lock is doing it's job letting the plunger move around, hence the wear on the sides of the spring. Going to replace the spring. In the meantime I put a .188 spacer in the cap under the spring for a little more preload. Quited it right up.

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Yes, I removed the big tension spring down low and removed the tensioner and spring mechanism when I installed the chain. I then reinstalled the lower tension spring and when I went to re-install the upper auto tensioner I installed it without the spring and hollow bolt in place. I then could not install the spring and hollow bolt. I had to back out the 8mm bolts to the edge of their threads to allow the spring and retaining bolt, then tightened the tensoners 8mm bolts down.

My old chain was worn to the point I could install the auto tensioner spring and thread the hollow bolt about halfway in before it even started to tension.

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. I had to back out the 8mm bolts to the edge of their threads to allow the spring and retaining bolt, then tightened the tensoners 8mm bolts down.QUOTE]

DON'T DO THAT!!!

You will be putting too much tension on the chain. Did you release the ratchet in the tensioner so that it would retract before you installed it?

Ride on

Brewster

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Yes totally retracted, its just my tender little fingers couldn't muster the pressure the other way. It's in proper. (As proper as a factory ratcheting chain stretcher can be anyway...) I think I want one of the manual jobs. Makes more sense to me than the oem one stretching that chain every chance it gets!

BTW my bike has a manual compression release installed. Better or worse than auto? what about the Drill on that, TDC, Kick. seems to have been working so far. Also saw that it had the Stroker Idler gear installed while I was in there.

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ACR (auto compression release) is a gem when working correctly. If you can, convert! There is always someone parting out a KLX on eBay. If you don't have access to an ACR already.

Make sure that Brewster checks it to see that the ACR is in the correct position on the cam. Many of the older KLX's had it installed out of position from the factory.

Karl

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