Blown Up?

2tken

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May 20, 2024
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Hi all. I'm new to riding my blaster. It's an 04 deleted oil, deleted tors,
I was ridding the other day when I heard a pop from under me. I figured a backfire. But it started running like 💩. Very low throttle response, bogging out and such. Cut out at a stop sign and won't start now. It was running great before this. Running about 32:1 oil. Got a vitos carb i was going to install, but I would like to know your take on what happened. Did i blow it up? How would I check if so? I can push the kicker down with my hand, but not too easily. Not sure what to do or what to check.
Appreciate the help.
 
A backfire can shear the flywheel key which will adversely effect your ignition timing to the point that it might be difficult to start or won't run at all depending on how far the flywheel has shifted out of proper placement . But a compression test is simple to do and will be the most logical first step for you. If compression is good, the next thing I would check is the flywheel key based on what you are describing.
 
Turns out I only have 40psi of compression. What to do next? Rings? Piston? Not sure
 
Hate to butt in lol.. but my new to me blaster lost power yesterday and won't start now and I checked the compression only have about 35psi lol so similar problem but I didn't hear any pops or bangs. I'm guessing the rings are fried but very new to this 2 stroke thing.
 
In terms of compression needed to run, 2-strokes really aren't different than 4-strokes.

Whatever you guys find when you pull the top end, you need to figure out why you had a catastrophic failure that caused such low compression. There can be quite a few different causes, most common with a 2-stroke would be a lean condition caused by an air leak. Base gasket, crank seals, reedvalve gaskets are the most common.

Evidence of a lean burn-down with loss of compression would be in the form of the piston crown on the exhaust side melted away as well as aluminum streaking on the cylinder wall. The aluminum streaking in the cylinder wall is piston material that stuck to the cylinder wall when it began to melt. Often times this causes stuck compression rings and loss of compression.

Please keep this thread updated with what you find. 👍🏻
 
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In terms of compression needed to run, 2-strokes really aren't different than 4-strokes.

Whatever you guys find when you pull the top end, you need to figure out why you had a catastrophic failure that caused such low compression. There can be quite a few different causes, most common with a 2-stroke would be a lean condition caused by an air leak. Base gasket, crank seals, reedvalve gaskets are the most common.

Evidence of a lean burn-down with loss of compression would be in the form of the piston crown on the exhaust side melted away as well as aluminum streaking on the cylinder wall. The aluminum streaking in the cylinder wall is piston material that stuck to the cylinder wall when it began to melt. Often times this causes stuck compression rings and loss of compression.

Please keep this thread updated with what you find. 👍🏻
Awesome information I certainly will thank you sir 👍🏻
 
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