McCulloch Super Pro 125c build thread

[Bigmac]

I would look for a piston a little longer before I sent that one in, it will clean up ok for an old bore, but new plating would like a new piston. And there is usually damage that needs welding and boring to fix, just to so you know before you send it in, there is a good chance they charge you for that.

 

[Bigmac]

It's just conversation but I don't think even with a 60 over standard compression it would do much running a Tilley HS or the Walbro sdc or whatever it is .Then if you used an HR or a large HL you'd need a sloper and most likely more reed area .All that riggen would stick 6-8 inches above the air box .
I've seen vid clips that was supposed to have a 101 but obviously with a chainsaw carb and they didn't run any better than a stock 125 .One the other hand Gerry B talks about a guy he used to cut with who had a souped up 101 that could cut 60 inches of red wood in about that many seconds .He said it would throw a chain farther than he'd ever seen and tear up half the drivers doing so. Scares me .

Al, I haven’t seen any high comp pistons, you can mill the head and change head gasket thickness on a 101. All of the pistons I have seen are flat top zero deck, not that they didn’t exist, but I haven’t seen any. I agree that going .060 wouldn’t increase the comp much but I bet it would pick up some torque, not much, but some more low end grunt

 

[p61 western]

Didn't mess with the piston yet. I did pull the bearings off the crank. Probably the most stubborn set I have ever ran across.

 

[p61 western]

I will clean up the crank and maybe the piston tomorrow.

 

[Steve]

I would look for a piston a little longer before I sent that one in, it will clean up ok for an old bore, but new plating would like a new piston. And there is usually damage that needs welding and boring to fix, just to so you know before you send it in, there is a good chance they charge you for that.

+1!

 

[p61 western]

Hopefully I can find a new piston. I would feel better about it for sure.

 

[beaglebriar]

Dis mf'er done yet?

 

[p61 western]

Dis mf'er done yet?

No just getting started, and coming up with a plan.

 

[beaglebriar]

No just getting started, and coming up with a plan.

Is there a good source for stock pistons or do you try to find NOS?

 

[p61 western]

Is there a good source for stock pistons or do you try to find NOS?

So far no luck either way

 

[beaglebriar]

So far no luck either way [emoji3525]

I'll keep my eyes open bud. Check with the Definitive one, he may be able to point you in the right direction??

 

[p61 western]

I'll keep my eyes open bud. Check with the Definitive one, he may be able to point you in the right direction??

If I get a Kart rod and bore it then the piston problem is easy to solve. I'm going to think on it over the weekend and make some calls on Monday. Terry Ives is about 20 minutes away from me, so that is kind of nice.

 

[beaglebriar]

If I get a Kart rod and bore it then the piston problem is easy to solve. I'm going to think on it over the weekend and make some calls on Monday. Terry Ives is about 20 minutes away from me, so that is kind of nice.

I don't know who that is but he sounds important. LoL

 

[p61 western]

I don't know who that is but he sounds important. LoL

Lol he's a Mac kart building legend who has lots of parts.

 

[beaglebriar]

Lol he's a Mac kart building legend who has lots of parts.

Ask him nicely if I can have one of those karts. Always wanted one. [emoji16]

 

[p61 western]

Ask him nicely if I can have one of those karts. Always wanted one. [emoji16]

Lmao that might be asking a bit much.

 

[beaglebriar]

Lmao that might be asking a bit much.

I said "ask nicely"...say please n chit!

 

[jacob j.]

Lol he's a Mac kart building legend who has lots of parts.

Terry Ives is the MAN when it comes to McCulloch engines. The only people that know more about McCulloch two-strokes are the original Mac engineers.

 

[p61 western]

Terry Ives is the MAN when it comes to McCulloch engines. The only people that know more about McCulloch two-strokes are the original Mac engineers.

It would be really cool to actually get to meet him. Art Martin lived near me, but by the time I knew it he had already passed sadly.

 

[WOODS]

If your piston is usable I would stick with it. Unless you stumble upon a better one, changing it out as you now know will be $$$.

I would avoid a kart piston with the bearings in it instead of in the rod. Recently had a .050” over 101B rebuilt. Only made a few cuts with it. Left it with the builder for some fine tuning. Wrist pin took a walk and scratched the cylinder while he was tuning it. Found that this is not uncommon. Terry Ives has oversized pins just for that. Now I have the choice of re-lining or boring to .100” over and looking for a needle in the haystack oversized piston.

Don’t know how my 101B would have performed when broken in, but fresh it was not a wow compared to my stock SP125Cs.

If you just want it done and are up to another 2 bills, then purchase this piston and rod and have US Chrome bore and plate your cylinder. Make sure you get the right rings for the plating. https://www.ebay.com/itm/VINTAGE-RA...791092?hash=item591795edf4:g:S0kAAOSwOR9ba10x

Ron