TOPIC:

Hi all,
I'm thinking of getting an oversize (0.5)
Piston kit, and I've been told that the
Clearance between piston and cylinder should be around 0.02
Today I went to the nearest machine shop to find out how much it would cost
(66€/£53 per pot).
But my question is, should I be concerned
As he said he would only need one piston from the kit to do all 6 cylinder rebores
This goes against what I was told from the
German site which I might use to supply the kit.

Thanks Pete

No machine shop worth their salt would do a rebore without having all the pistons. Usually they will fit the pistons for each bore and mark the pistons so when you put it back together the pistons are fitted in the proper bores. Although in this day and age, the tolerances on new parts is a lot more close than it was 30 years ago.

53 pounds a bore hole is a lot. I can get them done here for $35 Canadian a hole and that's bored and precision honed. Probably even down to $30 a hole when doing 6 of them.

I paid £60 per cylinder for my re-bore. I gave them the head, all piston kits and the pages from the manual

When I got it back all of the piston kits had been opened but not marked. When I asked they just said they were all the same and it made no difference.

The manual does not specify a piston to cylinder gap. From what I could tell it was done with ring end clearance?

zed_thirteen wrote: I paid £60 per cylinder for my re-bore. I gave them the head, all piston kits and the pages from the manual

When I got it back all of the piston kits had been opened but not marked. When I asked they just said they were all the same and it made no difference.

The manual does not specify a piston to cylinder gap. From what I could tell it was done with ring end clearance?

It's in there on page 183. Shows as .031mm-.058mm. Replacement pistons should come with a spec sheet showing what clearances are required for their pistons. Forged pistons should not be fitted the same as cast pistons. When doing this kind of work one should follow the piston manufacturer's instructions otherwise you may end up squeeking the engine. Had it happen once and almost went over the handlebars. (Now there's an image I tried to forget)

There are no instructions or specifications supplied with the cruzin image kits. No help from them either.

£53 per pot does seem a bit expensive, even more so if there not bothered about taking measurements from each piston individually.
It's a bit worrying that I wasn't asked if the pistons are cast or not, remove too much and you end up with what you started with, an oil burner, and too little as kawboy mentioned and you might end up over the handlebars.
I'm thinking why don't I save myself a shit load of money and get a honing tool which are cheap enough and a set of piston rings as I cant feel a wear lip at the top of the cylinders, and that's it.