Need help with piston bearing

[eisle89]

Is there a higher quality roller bearing to fit what I think is the 12mm wristpin. I needed to
replace a piston and head because they were running into each other ( about an 1/8") around
the outside edge. The piston I got from DAX has too big of a wristpin. so now I guess I have
to find the bigger wrist pin AND a a roller bearing with the same ID assuming that the OD
is the same to all the cranks. Does anyone have a bearing chart for the different fits ?? TIA

[Bikeguy Joe]

I would have returned the engine before I took it apart if the piston was hitting.

Was your old wrist pin using a bearing or a bushing?

[eisle89]

Well, my big theory is that after awhile the crank might have stretched a little and
the upper crank arm was sliding side to side on the roller bearing itself.
The engine is an old powerking 80 and I'm trying to figure out how I can use the 12mm
pistons from DAX and just replace the 10mm wrist pin and bearing. I did a search and read
through a bunch of posts where other people had the same trouble and replaced the bearing
and added shims.
I guess I'll try that ... or give up and buy another engine, but no one has just the engine
in stock right now. Thanks

[eisle89]

Yeah, it will have to be a new motor. The bearing cage slops around inside the crank
arm more than I want. Here's some pix though :

[ivan H]

Ok, I know this is a very old thread, & I have never heard of a piston hitting the head before unless the small end bearing has colapsed, which they sometimes do, they're low quality. You should normally have about 0.8mm deck height. The problem is they use a 13mm wide bearing & the bosses on the piston are almost 16mm between. Replace the bearing with a quality 10x14x15 bearing. Eliminates bearing float & support the piston properly

[vachon644]

If you're looking for 10x14x15 bearings that are of high quality, look into products for scooters : Scoot-tuning.com

[Goat Herder]

That does look like a nice bearing!