127 Piston ID
 

Hey all I have a 127 that my dad got for free. I got it running and used it the last 2 summers to cut my lawn. LOVE it. It always did have quite a bit of blow by and started hard. Towards the end of summer the only way I could get it to start was to bump start it by rolling down a hill. It looks to have cut a lot of lawns in its day so I decided to tear the engine down today. Pulled the piston and it has quite a bit of wear so it will have to be replaced. My question is how do I know if I have an original piston or and oversized? I am failing to find any kind of markings.

Please let me know!

Thank you!

Nick

Download the K series service manual and read it.
http://www.onlycubcadets.net/forum/s...ead.php?t=4646

Best way to know what size the bore is, is to measure it. Not with a tape measure either.....


Rolling a non running gear drive tractor down an hill is a good way to tear up a hydro. Not sure how it would help it start anyway. It's not like the trans will work in reverse like a gear drive.

I have the manual and I did not see a section about piston ID other than the standard size of the bore so that is why I asked here. Did I miss something?Other pistons I have worked on have sizes stamped some place but I am failing to see it here. Yes I can measure the ID but I was asking specifically about piston size.

I agree bump starting that way is not a good idea, but I was in a bind and could not get it to start any other way. Yes my battery was good. I tried a booster pack and also jumper cables to my truck and it still would not start.

Rolling down the hill worked the same as pull starting a tractor, it got got the engine turning over faster than it would with the starter motor. Don't believe me? Put one in forward and push it a little, your engine will move when the wheels move.

Only thing you missed is the math.... just measure the bore, or the piston. The book gives standard sizes, however much larger the bore/piston is from standard, that is how much over sized it is, if it's over sized at all. Piston should be marked. If not, it's likely standard.

No, I'm sorry, I don't believe you. A hydro transmission in neutral will not roll the engine. I don't need to check. If you moved the hydro lever to the forward position, it may move the motor some, but after one or two revolutions will stop rolling the engine. That was an extremely bad idea. I'd say the real issue was the hydro linkage wasn't adjusted correctly and it was trying to move the tractor with you're foot on the brake while trying to start it. Hopefully, you didn't damage it.

Thanks for the info on the sizes. You mentioned "Piston should be marked."
Where would it be marked?

Believe me. I did not say the tractor was in the neutral position it was in forward.

The linkage is working fine. With the tractor in neutral, the tractor does not move with the engine running or cranking weather the brake is pressed or not.

To get it to start I had it in neutral and got it rolling down the hill. I slowly pushed the "shifter" forward and as the tractor rolled the engine then began rotating once the shifter was out of neutral position. Once the engine rolled over fast enough, it fired off.

Again I agree not the best way to do it, but it worked and once it was running, it behaved normally.

On the top.

You ever overhaul an engine before?

Thank you.