How to release stuck piston rings?

[Muchmore]

Ok, so I have talked to several people and read countless threads but I need some advise. My daughter has a 50cc TTR and after it warms up it PUFFS smoke at all rpm's. I have had a few people swear by Chem Tec and Marvell but has anyone ever used them with success? IT has to be a broken or sticking ring but I believe it to be sticking instead of broken because it's only after it warms up. burnout

 

[Igofar]

pull the plug and pour in some MMO and let it sit a couple days. You'd be amazed at how well that stuff works.

 

[BakerBoy]

.... and leave out the spark plug when turning it over the first time to avoid damage from over-compression.

 

[Muchmore]

.... and leave out the spark plug when turning it over the first time to avoid damage from over-compression.

Shooting the plug at the dog is half the fun! [emoji1] Ok thanks guys that's the one I'll try!

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[timdow]

Hummm... well from what you say my money would be on carbon causing the oil control ring to stick when it expands. The MMO or any oil & solvent soaking would be a good start. If no joy there, you can try decarbonizing by spraying wather in the carb: https://www.youtube.com/watch?v=lsPk76RpqKc .

 

[Muchmore]

Hi Timdow I think we are talking about the same thing. I think there is carbon of done other foreign substance causing the oil ring of the piston to stick in when hot.

But water huh....I'll give it a try if the marvels doesn't work.

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[dduelin]

Years ago I had good luck using Brake Cleaner to free ring lands that were jammed up with soot and carbon. I sprayed large quantities into the spark plug hole after moving the piston up to TDC to close the transfer ports, repeated three or four times, then a squirt of oil to lube the rings before starting the engine. MMO works too just takes days instead of minutes.

 

[LetErBuck]

I have had very good luck using at least 91 octane fuel and Seafoam.

 

[SinNH]

MMO is my first choice for cleaning carbon, etc, it contains naplathine or something like that, but as mentioned to clean heads,pistons, etc to spotless takes many days, usually two weeks for me.
Pine Sol works too, but sinks.
With carbed bikes, as a triseasonal maintenance, I slowly spray MMO into the carbs with the mill at about 3000, usually some serious stuff exits the exhaust.

 

[Muchmore]

Ok thanks guys

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[OhioDeere]

Hmmm.. My experience is, if its smoking that bad you need to take the cylinder off to expose the piston and clean it up.. This is not a big job for that small bike.. new piston rings can't cost that much?
long ago I installed new rings in my kids bike.. new gaskets, rings I don't believe cost more than $15.. Bike ran like a champ after that for a long time..
Also get a chance to clean up the jug, hone cylinder wall and clean up carb.

 

[Muchmore]

I probably will need to do that eventually but I was hoping to spend $5 on marvel or something easier. I know it's a long shot but worth a try.

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[Muchmore]

Ok, I am going to eat a little humble pie here....I soaked it with Marvel and when I drained it I noticed there was WAY more oil then I put in. I pulled the airbox and it was full of oil so at this point I'm thinking what the heck is going on? Well, after I looked t my sons bike it was also way over filled so I questioned him about it and he said "Dad, I changed the oil on both of our bikes, mine and my sisters."

So how can I be mad, he changed the oil on both bikes, used the right oil but just way overfilled them. Jeez, I should have looked at that in the first place but I just knew the oil was ok, nobody has worked on the bikes but me. He is 11 years old and FINALLY started tinkering with mechanic'n I am so proud and a little humble I didn't follow my own troubleshooting skills : I swear I checked the oil before I started... good grief

 

[silverbub]

A teachable moment, for sure!...be sure he understands that the inside of the exhaust pipes do not need to be cleaned out by using a water hose!...we all had a starting point for learning our mechanical skills & needed guidance then & even sometimes now...reminds me, fondly,...so long ago while my father was working on the family car & i wanted to watch & learn(perhaps some words I later learned were somewhat OK to use in garage if no one else was around, but not in front of him or mom!)...he looked at me from under the hood with an obviously frustrated look & said: "WHY DON'T YOU GO ON OUT TO BACK YARD AND PLAY THERE!!!)...