How Critical is Piston Head Shape?

Hi Experts,

I'm rebuilding an engine (74' Honda CL200 bored out .5mm over) and I accidentally damaged the pistons that I had. Unfortunately, the place that I got them from is out of stock and probably won't order more from Japan for a month or more, so I'm exploring my options.

I've found 56mm 4 stroke pistons online, but the top of the piston looks different from what I was running. My question is, how important is the shape of the top of the piston and what should I know when I'm looking for replacements?

Here is what I want/was running: https://scramblercycle.com/products/honda-cb200-cl200-cb200t-piston-and-ring-kit-2-kits-50mm-oversize-new-rep?variant=2113436254232
Pretty much everything else that I'm finding is much flatter.


Thanks!
-Phil

Very important as it is going to affect both your compression ratio and possibly cause issues with valve clearance.

Hey advCo,

Good to know, so basically I should get the same exact shape or don't get anything at all, is what I'm taking away from that.

If anyone knows of a place to look for pistons I'd greatly appreciate it! Otherwise I'll keep scouring the internet till then.

Classic5 said:

Hey advCo,

Good to know, so basically I should get the same exact shape or don't get anything at all, is what I'm taking away from that.

If anyone knows of a place to look for pistons I'd greatly appreciate it! Otherwise I'll keep scouring the internet till then.

Click to expand...

Well, if you're going for stock then yes that's the answer.

ahhhhh, ok. If I'm reading you right, the follow-up answer is that: I could in theory run something different but I would need to know more about exactly how the change in shape would change the compression as well as making sure that it didn't cause any clearance issues.

Sounds like I have some learning to do.