Polini casting flaw

I sprayed soapy water all over the intake and cylinder while pumping air into it and found this. I see two small imperfections, the right one is on one of the transfers. I have not done any porting to thin the casting. I bought this cylinder used with very few miles on it. The piston that came with it was cracked on the exhaust side. It looks like the ring snagged the exhaust port within the first few miles. I bought a new A piston for it and chamfered all the ports before I assembled. I made my own intake and put a 17.5 dellorto on it that I had laying around. I was trying to get it jetted better when I thought I would check again for leaks. That's when I noticed bubbles coming from a place where they shouldn't. Is there any chance of repairing it or would Polini possibly replace it??? Maybe I shouldn't be buying used stuff???

image.jpg
image.jpg
image.jpg

Re: Polini casting flaw

'Cracked on the exhaust side' thats a pretty good chunk missing there. Never buy a cylinder if the piston looks like that

Re: Polini casting flaw

Overpriced Parts /

Ya that's not good .

What you should do is buy a new polini kit when there's a sale going on that way it's cheaper and you know what you got.

I'm running a used polini cylinder with my new piston that I got from someone

On one of my bikes But I got to examine the cylinder first before I gave the guy some money for it.

Still though buying a used cylinder and then buying a new piston cost almost as much as buying a whole new kit when they are on sale.

Re: Polini casting flaw

Try patching those leaks with JB Weld.

Re: Polini casting flaw

Clean the area real good with brake cleaner first, then apply jb weld, devcon, or whatever your high temp fuel proof epoxy of choice is like Stevew says.

Re: Polini casting flaw

I scuffed up the surface with a dremel and put a small patch over the crevices.

image.jpg
image.jpg

Re: Polini casting flaw

Pack it in tight over top that ,smooth it in with a plastic spoon so it will grip better, it wasn't leaking that bad it looks like.

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account