Honda gx620 oversize pistons?

[shadowkeeper49]

OK guys... I've recently acquired a Honda gx620 that is in need of a rebuild. My problem is finding a source for oversize pistons and rings. I know it will need to be bored as the cylinder walls are pretty rough. I want to make sure I can find the parts before paying my machine shop guy to bore it. Also I've heard that the 390 1.3 ratio rockers and springs will fit the 620 head, just want to verify. Thanks

[Dave in VA]

http://www.buggiesgonewild.com/big-b...s-manuals.html

I don't know if this will help or not...











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[shadowkeeper49]

As far as i can tell the gx390 parts will work just wondering if anyone has actually done it... Or if its even worth the $400 in parts...

[sho305]

I never saw a lot of aftermarket for the honda, but then I never looked hard. There is stuff for Kaw and Kohler and tons of stuff for vannys of course. There is so much stuff for clones because the gx390 honda was raced but never saw honda twin stuff.

Some pistons you can match up you just need the pin size, top height, and bore. You can cut the top down easy enough.

Is is worth it, if you want to build a performance engine its not unless you can find parts. If its worth just a rebuild and rev kit and that is what you want it could be. If you bore it and new bearings, its pretty much a new engine should last a long time and be able to sell it if you want to.

[sundep]

This is an old post, but adding this for future reference.

Oversize pistons are available for GX270 and are close to GX620 pistons.

Piston diameter same
Pin diameter same
Skirt in longer on GX270

Don't know about the piston height.

[sundep]

Same part numbers

13011-ZE8-601 +0.25
13012-ZE8-601 +0.50
13013-ZE8-601 +0.75

[sundep]

Found part number for available GX620 oversized pistons. 0.75mm oversize.

Piston 13104-ZJ1-841
Rings 13103-Z5H-004

I hope this helps the next guy.