Check your timing chain

Whilst out on a ride last weekend I noticed a new noise from the bottom end (apart from the usual clutch rattle). So I went and pulled her down again (2.5 hrs since doing the head :D ) Big end worn, little end worn, nothing too serious. When I did the head a week ago, I noticed the cam chain was buggered. Closer inspection finds that the worn cam chain has destroyed the lower sprocket, which is part of the LH crank web :) Was almost as cheap to buy the whole crank, as it was to buy the appropriate parts.

Barrel is also pretty shagged. To cut a long story short, I just ordered a compete crank assembly, main bearings, 444cc piston and a new clutch basket. Barrel goes away to get bored and replated tomorrow. So now the only 'old' bits will be the gearbox (rebuilt a year ago). So, with 444cc on board, a ported head and YZ450 cam I reckon the ol' 426 will go pretty hard again :)

Sorry to hear you had problems. But your experience is helping the rest of us. :)

I've got a timing chain on order right now. :)

such is life. At least the engine will be faster and quieter by the end of next week :)

My 02 wr426 only has about 325 miles on it and it make some noises that have been going on for a while. I've checked the timing chain and valve clearence and there is nothing wrong. I know one of the noises is the clutch, but the other noise I can't figure out. It's almost like a rattling noise like from vibration but it's kind of hard to explain. Is this normal, do they all make this noise?

My 00 wr400 makes the same noise.

It's like there is a loose bolt somewhere by the water pump or something?

Is that the noise you get?

thanks

sounds like it's time for a rod kit. Rip the barrel off, and check for wear in the little end. Both ends of the rod wear to the same time, so if the little end is gone, the big end is too.

Do you have an aluminum skid plate? If so, take it off and see if the noise dissipates. That thing reflects sound back at you which can be very disconcerting. I took mine off yesterday and rode around a bit and it was like I was riding a Cadillac. All the little clanks, chatters and vibes magically disappeared. When I put it back on, they all came back...SC

Why would it need new rod bearings? It only has 325 miles on it and it has made the same noise since just after break in.

Why would it need new rod bearings? It only has 325 miles on it and it has made the same noise since just after break in.
He thought you DIDNT know what it was and was replying. If you dont know what it is, then how do you know what it isnt? :) I suspect you are just hearing the gears banging. Common with straight cut gears. Does it the most under light to no load. I bet this is what you hearing as is normal. Usually its heard idling in neutral, pulling in the clutch makes it go away. This is the gear clash. Is this what you speak of? :):D

I was only asking why it would need rod bearings when there is so little miles on it, that's all man. When I pull in the clutch it goes away a little but not all the way.

I was only asking why it would need rod bearings when there is so little miles on it, that's all man. When I pull in the clutch it goes away a little but not all the way.

that post of mine was actually in response to the WR400.

These engines have a very mechanical sound to them, due to the very thin case walls, especially if you have a quiet pipe. If you ever ride your bike without a helmet (slowly, just for the exercise) you will be shocked with the noises it makes!

My 00 wr400 makes the same noise.

It's like there is a loose bolt somewhere by the water pump or something?

Is that the noise you get?

thanks

I read in a post one time that the 98-00 had a fairly common problem with something in the bottom end :) I dont exactly remeber what but it was updated by useing a splined shaft instead of a whole with a pin through the shaft that worn loose over time.. I think they said it was an easy fix also... you might try a search on it...

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