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rebuilding top-end *need advise*

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what part should i replace

-piston, rings, valve spring, timing chain

anything else also i saw some abnormal ware on the camshafts,and there are a few light lines in the cam journals, you can see them but cant feel, i guess when they did the valve recall they over torqued them.

i will try and get pictures of the camshafts it look like the plating on the lobes wore of and it only has 60hours on it do you thing yamaha would try and pick up some of the cost

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On my top end I replaced:

Cyl gasket

Head gasket

Coolant o-ring on the cyl

Tensioner gasket

Timing chain

Piston, rings, pin, clips

Cyl was soft honed

New valve springs

Valve seals

Be sure to use engine assembly grease on the piston pin and crank, on the cam journals and lobes.

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If it only has 60 hours on it, it would be nice to refresh the top end, but it should still be ok for at least another 20 hours. But all I would do is new piston/rings/wrist pin, gaskets, valve seals, and cam chain. And then go out and :censored:

I also suggest a high compression piston while you are in there, 13.5:1, Wiseco makes a good piston kit aswell as JE and CP.

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would i be able to put in new valve seal or would i have to take it to a shop also do i have to replace the valve keepers. thanks r

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On my top end I replaced:

Cyl gasket

Head gasket

Coolant o-ring on the cyl

Tensioner gasket

Timing chain

Piston, rings, pin, clips

Cyl was soft honed

New valve springs

Valve seals

Be sure to use engine assembly grease on the piston pin and crank, on the cam journals and lobes.

I am doing a rebuild and did not think of the Coolant O-ring on Cylinder. I can not seem to find that part. Do you have one

Thanks

D

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I am doing a rebuild and did not think of the Coolant O-ring on Cylinder. I can not seem to find that part. Do you have one

Thanks

D

If you didn't remove the steel line going into the head, I wouldn't worry about it. If you did, then you probably need one. Too bad you live too far away from me. I have a handfull of them. But it would cost more to send one than it's worth. I'd go hit up the dealer. Can't be more than .25c

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would i be able to put in new valve seal or would i have to take it to a shop also do i have to replace the valve keepers. thanks r

Use a meduim size needlenose plier. Once the valves & spring are off the seal is very easy to see. Grab the top of it with the needlenose & pull straight up.

It should pop right off. Sometimes you have to do this 2 or 3 times, but it'll come off. Another trick is to go get an inspection probe that has a hook on the end and you can use the hook to get underneath it & pull up. This should work too.

You may re-use the keepers. I've never seen one fail before, and I've rebuilt up a bunch of these YZF motors.

Replace the springs also. They are cheap, and although I've never seen one fail, I have heard of that happening. They are cheap enough that it's a no brainer. Also, replace the cam chain. You can't have too new a cam chain in these motors. It isn't a weak spot, but it was a compromise between weight & strength. The valves are light, and the springs are light. It doesn't take a very strong chain to spin them, so they used as light a chain as they could.

Good luck!!!

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what part should i replace

-piston, rings, valve spring, timing chain

anything else also i saw some abnormal ware on the camshafts,and there are a few light lines in the cam journals, you can see them but cant feel, i guess when they did the valve recall they over torqued them.

i will try and get pictures of the camshafts it look like the plating on the lobes wore of and it only has 60hours on it do you thing yamaha would try and pick up some of the cost

Put the cams back in the head with some oil or assy lube. Put the keeper back in place for the cam bearing & put the caps back on. Torque them to spec. Now try to turn the cam. It should turn very easily (until it hits the valve). If it turns easily, no worries. If it turns with a slight resistance, it still should be OK. If you have to muscle it to turn it (or they won't turn at all), the head is messed up and will need to be align honed to fix it.

Yamaha will probably not pick up the tab on that one, as it wasn't their fault it got over tightened (unless you can PROVE one of the dealer mechanics did it).

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