Quote Originally Posted by axa View Post
What a coinkidink, today i made the trek across the street to the veteran machinist at my day job, and that is precisely what he suggested i consider instead.
After talking it out it he seemed to confirm my suspicion that will be very difficult to find the right components to make the bore work...

First of all I cant find a CG piston that is wider than the stock ~66.5mm we have already... Then when I match it with another model, the wrist pin is often a different size than the 16mm required. Then i have to conciser matching the connecting rod... so on and so forth... Ive taken on too many projects like this, got to learn to be realistic.

Though we determined the real deal breaker is that there is no good way to know how much material needs to remain on the cylinder body or other components after machining to not fail.
Having an engine seize on me wont be a good way to find out...

I'm going to speak to the engine shop once more to confirm, but even if they are willing, i wont be a good price.
They wont likely be able to find anything i couldn't, wont be able to just order a a kit, the price will go through the roof.


Therefore it seems that a head job, port matching, cleaning the casting, and some polishing may have some potential on a very likely poorly machined Chinese engine.

And if there is any enough clearance, i will mill the head down.
Do you or anyone, happen to know how much, if any extra head clearance there is on our version?
Well,I've done this a few times.Find the over size piston with the proper spacing from wrist pin center to crown, but with a smaller pin diameter.Then offset machine the wrist pin journal in the piston to except the larger original pin.It increases compression and will require a deck height check and cc the head to make sure the piston and valves don't hit, and the CR isn't to high.A thicker cylinder base gasket will make up the difference,if it's to much or if piston valve contact will occur.I have also had teflon wrist pin keepers machined instead of using circlips.The last engine I done this way cost me $120 in machining and $200 for parts.It was on a go kart engine I saved from the scrap pile.I don't know the engine make or model.It was older and could have been yamaha or honda knock off.