hobbit athena piston clearance

naive and unaffiliated /

After having carburetor issues, I figured I’d pull off my Athena kit to see how it was holding up. Piston clearance had come up in a conversation Saturday night and it turns out it was a good idea to pull the head.

The piston isn’t always hitting the head, I only heard it on long, wide open downhill stretches maybe when the rod and piston expand a little more than the head and barrel.

Anyway, this has me researching ways to improve clearance like squish band, adding head or base gaskets…

Re: hobbit athena piston clearance

that is some serious serious contact there. also lots of yucky looking carbon on that piston.

just do what i do with the athenas and cut your own sqiushband.

Re: hobbit athena piston clearance

Didn't know this was an issue with Athena kits! I would try more base gaskets first because it is the easiest and most reversible fix. Peter, do you have any pix of your Athena kit?

In other news...

Did you just move down to a smaller jet? To my eyes, the plug looks lean. You might be able to case match that as well.

Re: hobbit athena piston clearance

i told ya mike good thing you checked it out. what pipe you running with the athena?

Re: hobbit athena piston clearance

Re: hobbit athena piston clearance

Thnx! Wish I could've made it back to LA to meet you peeps. Ah, poverty. At least giving half baked advice on an internet forum is free.

Re: hobbit athena piston clearance

I am glad we got to talk. I have Leo Vince pipe and the stock carb w/85 main, mixing around 32:1. I've got fuel flow problems, probably a sticky float needle.

I am gonna work on an intake to run another carb, probably a 19mm phbg and bring it out from under the frame. If I do get anxious and run that stock carb, I'll go to an 88 or 90 main and lean out the mix to something like 40:1 or more.

That's such a clean squish band. Did you do it by hand?

Re: hobbit athena piston clearance

i believe cappy did it first, quite a lot of info on it here in his thread:

https://www.mopedarmy.com/forums/discuss/read.php?f=7&i=137512&t=133294

Re: hobbit athena piston clearance

cutting squishbands by hand is easy and has been done for years. i only did it out of necessity. it took like 30 minutes.

Re: hobbit athena piston clearance

Hey Peter what tool did you use to cut your squishband?

Re: hobbit athena piston clearance

If you add base gaskets you will change the port timing slightly.

You are better off working on the top, either a thicker head gasket or by machining the head for clearance.

Re: hobbit athena piston clearance

a dremel and some sandpaper :)

Re: hobbit athena piston clearance

naive and unaffiliated /

That's what I got started on it with. Mostly using the mark in the head as a guide.

Re: hobbit athena piston clearance

trace the headgasket with a sharpie silly!

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