My cylinder troubles

[Nightbiker07]

well, the stroke was checked on my motor, and it checks out OK, eliminating the possibilities of the bottom end being wrong.
the piston is correct, and the sleeve is correct.
after much research, it seems that the cylinder is too tall, and the bottom must be cut.

i dont understand this at all. but according to PR racing, this is the only thing it could be.

[cr480r]

have your cases been machined? What are the chances of the cylinder being too tall? how far off is it?

[Huffa]

How about I measure the one I have, see if they are the same ?

Well I measured mine from the top fin to base but it's hard to measure real precised .

At the best location where it would be the most accurate I got 4 & 5/8 .

Don't go by measurement you see in pic, it's deceiving because of angle, just showing you what location I measured at.

Thats the side of the reed cavity below tape measure (bottom of pic)

[Nightbiker07]

the cases have NOT been machined, i compared them to the other 2 bottom ends i purchased from ebay.

it was significantly off.

PR checked everything else they thought it could be. stroke, piston wrist pin location, this that and whatever. they didnt compare sizes of the cylinder to what it should be, but alot of people have had good things to say about them, and they have been there for a long time, so i doubt they would go machining a jug unless they were sure that was what had to be done.

if not, theyll be buying a new jug. but i talked to the guy alot, and made sure this was the best option, including the fact that i dont want this mod to be a problem when i rebuild it down the road.

hmm. maybe next time i have the top end done, i will have it ported and polished.

[Daddio]

Is it a 250 cylinder or a 300 cylinder? Is it a stock piston or a wiseco? There is no wiseco piston made for the 300 cylinder but there is one made for a kawi jetski that will fit but the cylinder has to be modded to accept it. It could be that the wrist pin is in a different position making the deck height on the piston different from the stock piston.

[SYKO]

im thinking along the lines of the wrist pin location on the piston isnt correct

[Nightbiker07]

they checked the piston with a phone call to wiseco, and it is indeed the correct piston for the L.A. sleeve.

if it does wind up bein the piston, ill just have one just like it with a larger bore ordered from wiseco. yeah, it might cost a bit more, but its the only option now, as the work is mostly done by now.

if needed, i can fabricate a spacer plate and have it welded to the jug down the road.

[bigreddaddy]

I'm going to be rebuilding my 350cc top end very soon (my first one) and this thread is making me nervous! LOL JK

I hope that your motor really works out for you man, I know you have a lot of $$$ by now.

[Nightbiker07]

yeah.......it would have been much cheaper to buy a mint, raced up R off ebay........