Maxwell, Fernie, Snopro....XP help please

[retiredpop]

I'm not sure about his sled specifics but I know he upgraded to 91 over the 87 for the head milling but it was very minor machine work, that being said 2smokes are pretty picky, he said he didn't run the choke after the parking lot and was just trying anything to get it to fire after it died, he's going to drop it back off with the shop he had do the work, ill try and remember to update their findings, thanks for the help everyone.

Thanks, it's always nice to hear what the problem is on these issues. It might help someone down the road.

 

[tantrumpipeline]

Thanks, it's always nice to hear what the problem is on these issues. It might help someone down the road.

You bet, I'm thinking the head is the cause, hole in a piston would be the most logical for the lack of compression and the cylinders were fresh plated and new pistons and rings

 

[duck]

I prefer to doo all my own engine work, 2 stroke engines are simple. Did they check the ring end gap and fit them on the pistons to the cylinders and make sure there was -018-.020" clearance? The rings usually need to be filed a bit to get the proper gap in order to stop them from catching the port when they expand from engine heat. My guess is a part of the ring broke off after catching the exhaust port, went out the exhaust (hopefully) and you lost compression in the cylinder this way. To pop a hole in the piston top only occurs under high heat, high rpm at full throttle in a lean condition and/or high compression and yours sounds like it was babied on the trail.
Just my thought......

 

[tantrumpipeline]

There's a possibility of that but in most cases a broken ring gives you some sort of resistance when pulling it over, it was a reputable shop but everybody has bad days, hopefully it's an easy fix

 

[cdnredneck_t3]

Why was the engine re-built in the first place? Was it running, just low compression or did it calf the first time?

 

[tantrumpipeline]

Why was the engine re-built in the first place? Was it running, just low compression or did it calf the first time?

Blew the bottom end on the factory motor and picked up a used with 1800km or so and figured for good measure a top end wouldn't hurt, as far as I know anyway

 

[TROLLCAT]

it could have a bad crank seal and that could of caused the failure to