Why would my 250r cylinder crack?

[LathersR]

It cracked from the exhaust flange to the reed cage and broke a chunk off from the exhaust flange half way around the jug near the bottom

[JohnBeton]

intresting, got any pictures of that ?

[86 Quad R]

Originally posted by JohnBeton
intresting, got any pictures of that ?

X's 2 on that. :eek:

[C-LEIGH RACING]

What year model jug.
Ol 85/86 jugs were bad for that after a lot of porting & high compression.
With high compression, every time the piston goes up its trying to rip the jug off the cases & even more so if your not running the head stay.

Lot of times, the ol 85/86 jugs would beark just above the reed chamber & down through the side of the transfer ports on both sides, whole tail end of the jug break off.

The early model big bore Pro-x jugs had the same problem, except it would crack right in the middle on the side of the reed chamber & down through the transfer ports. Bottom portion of the reed chamber & jug break off.
Neil

[LathersR]

Thanks c-leigh that sumsss it up haha.. Its a 1986 jug and broke exactly where you said..and just had a fresh top end and no headstay

[jcs003]

my sleeve cracked on my 86 cylinder but i believe that was caused by excessive wear and piston slap.

do you got a pic of th damage?

[LathersR]

ill try to get one tonite no cameraaa

[250rPRIDE]

i also have seen a 85-86 cylinder do this, went to look at a used r and he said that the head was cracked well i showed up and it was literally broke in half just like the others have stated.. needless to say it matched the cracks all threwout the frame and i didnt buy the r

[Gregjy]

Crap I have a cylinder right now that did that. I was running the head stay though! Pisses me off it was a GOOD top end! Guess upping the compression was not the best idea!!!