Cannot diagnose ticking sound....

[markvan]

2000 yz 426. We have just about done everything but split the case. There is a loud ticking sound coming from the engine. To date we have put in new rings, the cylinder has some wear but is within spec. New valves, valve guides and seats. The crank is all within spec, and there doesn't seem to be anything out of place in the gears. Counterbalance gear is good, timing chain is good. There seems to be some play in the water pump, but doesn't show any physical signs of wear, perhaps this is just normal. Also the sounds seems to be coming from further back. I have had the bike in the shop for 3 months and he cannot find anything wrong. We have checked and double checked everything. I really don't want to split the case, as I am going to have a large enough bill to pay as it is. Any body have an Idea what is going on here?

Obviously the next logical step would be to split the case and keep looking, but right now I just want to get my bike back on the trails.... The shop says to just ride it and see what happens, if something goes they will replace parts at cost and give a deal on the labor, if it's some I can't handle myself. It is tempting to do but I really don't like the idea of riding with this really loud ticking sound. Something is definitely not right. Any ideas? Thanks guys...

[motorhead2825]

I have an 06 yz 450 and have the same issue since it came from the crate. At first I thought it was the counter ballance being loose on the gear. So I tore my bike apart last night and found everything in tact. My water pump also has a little play in it but the bearing and seals are good. So I split the case and and still have found nothing. That damn ticking is driving my mechanic and I mad! But we can not find any thing that would cause it everything still looks like brand new. I think that every once in a while yamaha just produces a noisy engine. So the only thing I can do is ride it until something happens, I dont like the sound of it but there is nothing else that I can do everything is still in spec. So if I were you I would not go through the trouble and split the case I dont think that you will find anything.

[grayracer513]

The frequency of the sound will help you find it. Valve related noises will occur at half engine speed, crank related at engine speed, stuff in the trans or primary drive may happen at some off speed frequency because of the gearing. Con rods will produce a double rattle as it goes over top, may vanish under a load, and worsen when the throttle is closed at higher rpm. Piston slap will usually do the opposite; worse under a light load than off the gas.

[cuddies say YEE 925]

are you SURE its coming from the motor? are you suspension bushing bad? is it your chain slapping? sometimes its simple things you might now know? just some thoughts

[markvan]

Definately engine, no question about it....it just came on suddenly when riding..(stopped for a bit, let off the clutch easily to start moving forward and suddenly was there...)

Sound seems to be somewhere in the lower half... to the rear......

[cuddies say YEE 925]

tranny gear?

countershaft?

i was first going to ask if it was the timing chain, but you said you looked at thta already.