Warrior top end

1998yamahawarrior said:

Actually most shops will want the piston so they can hone the jug to the proper clearances. Most people consider .020"(83.5mm) over to be the first bore. Most machine shops can do some measurements and tell you how far it would need to be bored out to clean it up. Usually though .040(84mm) is all the bigger you would need to go. You could also go the route Ive taken, I picked up an extra jug and head so that Ill only have about a days worth of down time.

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Thats good in theory.. But I had an old 465 that I had to rebuild, I bought a 85.5 piston for it (stock bore is 85)..
Took it in to get the bore cleaned up, and found it had already been bored to 86. So I needed an 86.5 piston.. I ended up having to return it, and wait for a piston anyway..

Thats reason #2 why I picked up extra parts, but if they dont have the piston since they can sometimes vary by just a little bit and they bore it to the exact size he could end up with either to tight of clearances or loose. If he dont mind the down time or doesnt want to pick up extra parts, Id suggest taking it to a shop after its torn down and having them measure so that you are getting the right parts and clearances. Ive tryed to cut corners on things in the past that have come back to bite me and I had to redo them right the 2nd time. Im making sure my 366 biuld is done right the first time, Id really like it to last quite awhile without haveing to tear it down for something(other than a simple cam change if I dont like the megacycle)

How much can it be bored before needing any new jets or adjustments? I'm thinking about a wiseco piston too if that makes a difference

Thanks for all the help and info guys. I'm hoping to get on this little rebuild after i figure out my newest problem which i posted about... it seems to never end haha