Puch wrist-pin bushing reaming....how w/o proper tools. tools?

Hi everyone, I'm getting ready to put a 65cc Airsal kit on my za50, I'm aiming for a low-mid rpm setup that will reliably go 40-45 with "stock-like" reliability. I THINK I have the timing/jetting "thing" down now but don't really have the tools for measuring/reaming of the wrist-pin bushing. Or should I (can I get away with) just running an out-of-the-box replacement since I'm basically building a "thumper" ?

I have 20-36 gearing, 15mm Bing, and (currently) a Circuit pipe.

Thanks in advance.

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

It would be difficult and that's why they go to all the trouble of making reamers. Once you get the new bushing in (freeze it before inserting) you can measure it. See how easily it fits the pin before you press it into the rod. A clearance in size all finished of .0005 is nice. The bushes are cheap so you could experiment. How about rolling 320 grit sandpaper on a round pencil until it just barely fits in and rotating it until it barely accepts the pin. Or you could freeze the pin and press it in for an interference fit and then rely on the pin floating in the piston for the bearing surface like some cars. Drill holes in the piston so oil can splash in. Get bigger bearing surface that way. If you used the pencil method on the piston bosses that might help too. You could pioneer the method for us

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

The tools aren't really expensive, you could get a caliper and a reamer for under $30. It's just bronze so HSS would probably be fine, no carbides or anything like that.

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

Thanks for the tips guys, I'm wondering if the last one I got from treats was "defective" since the wrist pit slid right through the bushing with no reaming at all? I did drill an oil hole and following the summer riding season disassembled and the bushing had rotated about 30deg. and the hole in the bushing no longer lined up with the con-rod hole?

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

Treats did have a batch of them a while back that were poor quality. Due to the soft material pressing the bushing in will cause it to deform slightly, which is why it has to be reamed to the final diameter after installation.

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

Overpriced Parts /

If kit do not waste your time doing a half ass job that even a stock 2hp cylinder will blow after a few miles

Get the cheapest needle crank you could find pressed in like 80 bucks

You're going to go through all that trouble experimenting with it and Will be so less than perfect and your kit and engine will go boom (edited)

Re: Puch wrist-pin bushing reaming....how w/o proper tools. tools?

If your bushing isn't bad don't mess with it

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account