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How far do you go with top end rebuild.

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Times coming to do my first top end on my 15. Right now im at 38 hours and figure I should get the top end done somewhat soon. We checked the valves at 29 hours and they were still right in spec. MY question is, are you guys doing valves as well when you do the first top end? The reason I ask is because the price doubles when you add the valves and machine work. Ive heard a few different opinions but curious what you guys have done?

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No valaves.  Just piston ,rings,gaskets clean carbon from the bottom of the head and deglaze the cylinder walls.

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do you see the valves coming out of adjustment more often? Do you do the timing chain?

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ive never changed a chain yet but i have not had a bike past 115hrs. We do top ends at 40-50 and would do a complete bottom end at around 100hrs.  Ive only had to shim 1 valve in all the kawis ive owned.  Really it didnt need it it was in spec but barely. I just wanted to do one once. My last top end i had taken the valaves out too and cleaned carbon off them

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You answered your own question in the word "REBUILD"

On the initial "build" you dont say "how far do I go?" You install everypart. This is what a REbuild is. If you just need a new piston. That is a replacement, not a rebuild. Everything in there wears. To RE build something, is to BUILD it...again. 

Only you can see/measure for wear. So if youre not trying to replace everything, you need to measure everything. Or have to go back in too soon. Funny how a motor was "rebuilt" and blows at two hours. Thats cause your average half asses it. Thinks..."thats all it needs".

When they dont even have a service manual nor a vernier caliper.

Take your time. Cover your bases.

This is a thousand dollar machine.

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14 hours ago, notoriousE-R-I-C said:

You answered your own question in the word "REBUILD"

On the initial "build" you dont say "how far do I go?" You install everypart. This is what a REbuild is. If you just need a new piston. That is a replacement, not a rebuild. Everything in there wears. To RE build something, is to BUILD it...again. 

Only you can see/measure for wear. So if youre not trying to replace everything, you need to measure everything. Or have to go back in too soon. Funny how a motor was "rebuilt" and blows at two hours. Thats cause your average half asses it. Thinks..."thats all it needs".

When they dont even have a service manual nor a vernier caliper.

Take your time. Cover your bases.

This is a thousand dollar machine.

Well said.   My sons 15 kinda blew at 32hrs.  It had a thrust washer go out on the crank. Dont know why. Anyway fine shavings went completly threw it. I have a friend who is a MMI grad do my bottom ends. We replaced everthing including oil pump and water pump and every bearing. Only thing we didnt replace was the head parts . We just flushed it clean. Bike ran great after that.

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 Every 50 hours I put in a new piston , rings , all new valves , and get the valve seats machined to fit the new valves. All together costs $560 Canadian. I do all the work except the machining. For my riding pace ( Intermediate ) Usually the motors are on their last legs at that point. Hence why I have a practice and race bike. 

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