I managed to demolish the engine pretty badly ... With pics

[jake]

Thanx Quan-Time for the tips and offer of help, ill give it a go myself and see how i go, ill proably take it to get my valve guides re done, and ive already put in a new cam chain, so no drama there, ill try and inspect it all and get back to you guys.

[youngy]

Do you mean that the pistons are called "4NX" and some valves "3LD" and other valves have nothing on them?

Other valves have mucho carbon on them. All valves are marked 3LD.

[youngy]

Thanx Quan-Time for the tips and offer of help, ill give it a go myself and see how i go, ill proably take it to get my valve guides re done, and ive already put in a new cam chain, so no drama there, ill try and inspect it all and get back to you guys.

Jake was this the first time it was run after the new camchain?

[jake]

No it wasnt the first time it ran, we been riding it for a few weeks now, thats why its so odd.

Another Question are there any rebuild kits that include valves and all that jazz, or somewhere online i can get it cheaper, because they want $90 for one exaust valve and $50 for intake, its a rip off.

Any help appreciated. cheers

[haggisbash]

Looks to me like the at least one of the exhaust valves in the other cylinder was about to go the same way too. Looks bent in the picture, so what was the cause? Lack of oil? Exhaust cam too tight? Cam chain jump a tooth? I'd want to know why it blew before I spent any money on it else the rebuild might end up the same way

[youngy]

If it's run before without a problem I'd doubt it's a cam cap overtightened. I'd want to look at the timing gear on the crank. Maybe there was a tooth missing before, and that caused the chain to jump? Or lack of oil. Or tensioner failure.

[Quan-Time]

No it wasnt the first time it ran, we been riding it for a few weeks now, thats why its so odd.

Another Question are there any rebuild kits that include valves and all that jazz, or somewhere online i can get it cheaper, because they want $90 for one exaust valve and $50 for intake, its a rip off.

Any help appreciated. cheers

someone on here once said a place to buy em online. it MIGHT have been a german place, cant remember..

For $90 a valve, fuk me, it better be stainless and come with a new retainer cap / collars.

There is another valve that fits perfectly, from another bike.. I cant remember which it was, but someone listed a part for it once.. But its prolly the same price. Valves that are "genuine" you pay more, but non "genuine" would be just as good. They are possibly made in the same factory.

Look at holdens factory in elizabeth, adelaide.. We also have Monroe shocks here in adelaide. You go to a holden dealer, you want genuine factory shocks, you pay WAY more.. Get your own shocks from any shop (monroe shocks) and put em in yourself / pay someone to do it.. I can tell you now, they are 100% IDENTICAL.. all they do is put a different sticker on if its "genuine".. They are the same shock, just different box / sticker.
I suspect there is a valve company who makes the valves for yamaha.. Find out who that is, cheaper and same

[brockzila]

well im going to have a head with a run cam bearing but every thing else is good on it if you want it, going cheap, you pay the freight and its yours. i could even strip it and send you the bits if you like to save on freight. you just have to give me a few days to sort my bike out befor i can strip it.