KDXRIDER.NET

I'm still learning a ton about this bike so bear with me. I have the engine mostly stripped down. Has a couple broken springs causing it to be stuck in first. As I was taking the jug off to get a good look at things I noticed it has a 68MM piston and sleeve? So someone at some point put a bigger piston and sleeved the cylinder. Which kinda has me guessing at what to do next. The cylinder walls look okay except on spot where the piston was sitting for like 3-4 years. I am guessing the correct way to fix this is to have it re-sleeved and coated. Since it's sleeved do you think I could get away with some wd40 and green scotch brite? Or is that a total waste of time? Not sure why the piston rings are completely flat on one side either?

Oh and this is out of a 84 model

For some reason the images aren’t loading for me, but I guess if the cylinder is smooth and not egg shaped (take measurements throughout) I suppose you could hone it. The other option is to just buy a used cylinder that isn’t sleeved on eBay for the superior heat transfer and durability (if that’s even the right word)

It sounds like someone sleeved it at some point. I would try to clean it up by hand, then go from there.

The pics are not showing up.

I don't know where you could get a 68 mm piston.

Wossner is the normal recommendation for a 1983 - 1985 piston, but it is 66 mm. I see they make a 67 mm, but that is as big as it gets.

Wiseco pistons for 1986+ do not have the piston ring pins in a safe place for 1983 - 1985.

https://wossnerpistons.com/products/8093

KDXGarage wrote: 06:39 pm Dec 24 2019 It sounds like someone sleeved it at some point. I would try to clean it up by hand, then go from there.

The pics are not showing up.

I don't know where you could get a 68 mm piston.

Wossner is the normal recommendation for a 1983 - 1985 piston, but it is 66 mm. I see they make a 67 mm, but that is as big as it gets.

Wiseco pistons for 1986+ do not have the piston ring pins in a safe place for 1983 - 1985.

https://wossnerpistons.com/products/8093

If the piston was still okay and the ring pins are in the right place, I’m still not sure if there’s rings out there that would work.

68 is around KDX220R size, is it not??

KDXGarage wrote: 06:53 pm Dec 24 2019 68 is around KDX220R size, is it not??

I don’t have one so I wouldn’t know.

Educate me on ring pins?

The piston has pins in the ring lands. This keeps the rings from spinning & catching a port. Called "Dykes" rings.