Ring Snagged Exhaust Port

douglee25

m3booooy
Location
South Jersey
I rebuilt my motor last summer and it's been running fine ever since. Yesterday I rode for maybe 20 minutes before I decided to stop for lunch on the beach. I had my sandwich, checked the plugs for the heck of it, threw them back in, started it up, and proceeded to ride away. I got 15ft. out and I lost all power. It was running on one cylinder. I thought maybe I disturbed a plug wire and it needed to be trimmed. I pulled it back in and I had spark on both plugs. I checked compression and I had zero on the front cylinder.

The results: It appears the ring snagged the exhaust port. I pulled the entire motor down and I couldn't find a screw missing from the reeds, no carb screws missing, nothing. The crank appears to be fine. No metal was down there at all. It all went out the exhaust. I found a piece of ring in the pipe.

Gotta love it! :banghead::banghead:


Doug
 

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keefer

T1
Location
Tennessee
How much compression were you running? If you were above 185 and running pump gas it could have been a piston failure due to too high EGT superheating the piston and making it break like that. I have seen several engines fail like that when pushing the envelope on the old compression / octane / timing tightrope.
 

douglee25

m3booooy
Location
South Jersey
How much compression were you running? If you were above 185 and running pump gas it could have been a piston failure due to too high EGT superheating the piston and making it break like that. I have seen several engines fail like that when pushing the envelope on the old compression / octane / timing tightrope.


I was running a whopping 160psi compression. :biggrin: I just checked it last week believe.

Doug
 
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