Piston options from other non-305cc engines?

[65ShelbyClone]

I've been looking around on the net and either I'm not looking in the right way or 305 pistons actually are hard to find.

Anway, I found some mention that sohc CB750s are 61mm and that CB350 slugs are 63mm and that early XL175s are also 63mm STD.

Do any of these share the compression heights and dome shapes needed to make them useable? The reason I ask is because my CL77's bores are alread .50mm over and there is some really deep rust pitting that will need at least another 1.00mm to get rid of. It would be nice to not repalce the cylinders and still be able to find that large of an oversized piston and rings.

[piecutter]

Check westernhillshonda.net . They usually have them. You really need to get the finished bore size first, before you know which size to look for. With that bit of info I can provide you with the part numbers to check for.

[LOUD MOUSE]

As I do lots of engine rebuilds I have purchased CB/CL72/77 pistons and rings.
Where the 750 pistons will install OK they are flat topped.
I don't know about the others. .........lm

I've been looking around on the net and either I'm not looking in the right way or 305 pistons actually are hard to find.

Anway, I found some mention that sohc CB750s are 61mm and that CB350 slugs are 63mm and that early XL175s are also 63mm STD.

Do any of these share the compression heights and dome shapes needed to make them useable? The reason I ask is because my CL77's bores are alread .50mm over and there is some really deep rust pitting that will need at least another 1.00mm to get rid of. It would be nice to not repalce the cylinders and still be able to find that large of an oversized piston and rings.

[65ShelbyClone]

I'll have a looksee at westernhills.

LoudMouse, is the "flat top" part bad simply because it lowers compression or are valve reliefs an issue? If it's just compression, I do have a very small Garrett turbocharger......

I'd actually rather just knock the old sleeves out and make some new ones, but I don't work in a machine shop anymore. I found some CL72 sleeves on "that" auction site, but I don't want to give up the displacement.

[LOUD MOUSE]

The flat top will lower compression quite a lot and the valves are not a problem.
You may want to remove the sleeves by putting the assy in the oven at 300 for about 30 minutes and dump the sleeves out.
I have used sleeves that can be installed and take a .75 bore.
Those 250 sleeves are undersize for even a standard piston. .........lm

I'll have a looksee at westernhills.

LoudMouse, is the "flat top" part bad simply because it lowers compression or are valve reliefs an issue? If it's just compression, I do have a very small Garrett turbocharger......

I'd actually rather just knock the old sleeves out and make some new ones, but I don't work in a machine shop anymore. I found some CL72 sleeves on "that" auction site, but I don't want to give up the displacement.

[65ShelbyClone]

Those 250 sleeves are undersize for even a standard piston. .........lm

Right, I wasn't wondering if they would take a 60mm piston, just looking at them as an option for replacement sleeves.....at the expense of 55cc.

I know you know already LOUDMOUSE, but for those that don't, this is why I'm exploring big overbore pistons:



I'm not even sure that a 3mm overbore will take that junk out. I thought it was bad when I pulled the engine apart, but I bead blasted it and all the rust was removed and left the really knarly voids in the pic.

[LOUD MOUSE]

That cylinder is trash fo sure. .............lm

Those 250 sleeves are undersize for even a standard piston. .........lm

Right, I wasn't wondering if they would take a 60mm piston, just looking at them as an option for replacement sleeves.....at the expense of 55cc.

I know you know already LOUDMOUSE, but for those that don't, this is why I'm exploring big overbore pistons:



I'm not even sure that a 3mm overbore will take that junk out. I thought it was bad when I pulled the engine apart, but I bead blasted it and all the rust was removed and left the really knarly voids in the pic.