piston struggling-HELP!

J

justthisguy1292

New Member
I had an expansion chamber but it had problems so i took it off and road mufflerless a couple times. I've done this in the past but this time the engine seemed to get a little hotter than usual and it slowed down a bit. i used to max at 40 mph but now i could only hit 30mph after a few minutes of riding. then i put the stock muffler back on to see if it was because i had no muffler. the problem continued and worsened till after a fast run down a big hill the engine stopped dead. the piston got stuck. it didn't completely sieze cuz i was able to wd40 it and knock it lose and get it going again. Its still slow and vibrating alot in mid to low rpm's. should i replace the piston, engine block, both or something completely different? i've heard people suggest a whole new engine at this point but i want to keep this one going if possible. its got a shift kit and custom front mount on it that i'd rather not have to take off and reinstall on something new.
 
Running with no muffler caused your engine damage,its better to just get another engine.
You could just get the top parts: piston,jug and head,but you dont know how much of the engine is damaged. and i wouldnt run the next engine without a muffler.
 
so how does running it without a muffler damage it? I'm still not even sure whats wrong with it. everything looks find but when i put it together it just doesn't go as fast. the Piston has too much friction. It seems like the only things that should have that effect are the seals on the piston and I can't see anything wrong with them.
 
justthisguy,
2 stroke engines require a certain amout of back pressure to run properly. Also with no pipe or chamber attached to the exhaust port there is excessive air drawn into the cylinder during the piston's downward travel which causes a lean running condition which can damage or destroy an engine. Replacement parts are available, check several of the sponsors you see advertising on the sides of this page but you might find a complete engine less expensive than the necessary parts to repair yours. Like Cabinfever said, don't run your next engine without a pipe and/or muffler. Also, sorry for the improper answer you received previously. It has been removed.
Tom
 
Thanks for the tips. I never saw an improper answer. was it because i stupidly put this thread in the wrong category? anyways i just wanted to report back what happened. I was skeptical that the engine could have been ruined that easily so after a day of sulking i put it all together for one last attempt and tried a heavier dose of oil and it worked! it took a minute but its back up to speed and seems to be running good as new. Not having a pipe probably didn't help the situation but i think i was just running too lean of a mixture to begin with. silly me.
 
in the future when a noob says his engine froze up, tell him to knock the piston loose, wd40 it and put in a heavier oil mixture. It might save the engine.
 
I'll add this... 2 years ago, I had a exaust pipe fall off while I was riding, & I couldn't find the bolts to put it back on; so I rode it home without the pipe on & it ran really well!!!
It was STOOPID LOUD!! but it ran faster than it ever had, & it didn't seen to hurt the engine, because that bike still runs fine to this day...
The only thing I was really worried about was dirt or rocks going into the exaust port & into the cylinder.
 
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