Refurbished 750

[cbfarmall]

Thought I'd share this with you guys, it being my 2nd post and all. I just finished this 750 that I've had torn apart since the summer. I felt it was running too unevenly and not enough compression. Tore it down and saw a lightly scuffed piston, and stuck and wore thin rings. Didn't take long to discover that I couldn't get any of the parts I needed to fix it up, so....

I cleaned up the piston as best I could. I had on hand 3 sets of Mac 101 kart engine rings. The thickness was perfect, but the rings were too large. I filed and ground them down to fit and reassembled with all new rubber parts.

One day, maybe, I'll restore it with new decals. But for now, it is a cutting machine. Got nearly 180 psi cold, without starting the engine. Once it's broken in, I'll check the compression again.

Here's the pics.

Chris B.

[lesorubcheek]

Awesome fix Chris! I didn't know the 101 was so close in size to a 750. After googling a bit, looks like they are only 0.025 larger. This is a great solution to these impossible to find rings. The saw looks great.

Dan

[billg]

That is an interesting fix. Ingenuity at it's best.

Bill

[mikevan]

Good fix Chris -

[MCS]

It's too bad we don't have a spec. sheet for rings. I doubt that Homelite had custom made rings for their engines so all that is needed is a bore size and ring thickness.
I have a '56 Chrysler 354 Hemi bored +.060 so 3 15/16" bore + .060 works out to 3.9975. I can buy 4" chevy rings for half of what a set of sixty overs would cost.
Anyone know if there is a parts manufacturer that sells small engine rings?

[lesorubcheek]

I've never ordered from them before, but there's Otto Gas Engine Works that may very well have rings for small engines. Look at www.pistonrings.net/. Not sure they'd have the thin steel rings used in the '50s or a 925 though.

Dan

[redsqwrl]

In regards to piston rings,
I found a link to a article at AS and found the bore of the 750 to be 57.1mm
I found a partner or poulan saw that had the same bore and bought rings. $28 bucks

the rings are to thick and I am having one set ground down to fit.

the other set I am going to save full size and then have the piston cut to accept the wider ring.

the go kart engine sounds awesome, It is way easier to file the end off than grind the whole ring down.
Awesome save on the 750.

Mike