cag prob's

alright, a freind of mine has a full fairing cag, never really had any problems. until recently, it was not starting at all. so first i asked what mixture and how old the gas was, well it was crappy oil (weedwacker oil) and it was quite old, so i thought the carb was gummed up. so, i cleaned everything in the carb out, put it back together, put fresh oil and gas in (redline 2 stroke perf oil) and tried to fire her up, no go. checked for spark, it had a strong blue spark, with 2 different plugs. so i gave up for the night.

*oddly enough there were several pops(backfires) from the exhaust* not sure what they where about.

next day, equiped with quickstart, we try again.a little quickstart in the carb and we try, no go. i notice a fair amount smoke coming out of the head and exhaust gasket/header. now, im not sure if that was just the quickstart being burnt off or not. while im down there i notice there is a small gap, 3mm or so bewtween the head and the gasket. now it gets me thinking, hes had this exhaust for quite a while. and could it of fried the piston???

*this was a new exhaust, not from factory, hence the reason it was NOT installed correctly*

recap
-bike has good compression
-is not a fuel delivery problem, it didnt even start with fuel directly down in the head.
-spark is strong

so, could it be time for a rebuild?. like i said before the bike backfired several times, and i told you about the gap bewtweent the head and gasket. could this of lead to the piston being fried?




sorry for the long post

update: i think this exhaust was meant for a lucky 7' he got ripped off by a dealer.

thats why it doesnt sit properly on the head.

take off the kill switch it might be faulty happens a bit to gopeds so it may aswell do it on a cag

did that to, forgot to mention in previous post.

Are you saying there is a gap between the cylinder and pipe? Pull the jug off and have a look. Sounds like top end is fried, but you said you got good compression.

yeah, thats what i found weird, keep in mind this is still my freinds bike, so i'll talk to him and see if he wants to bother or not

ill keep you updated.

gap between cylinder and case? or gap at the exhaust between pipe and e-port?

pipe and exhaust port.

hey there! hows things by now? give me a crack at this?! well done beeing so descriptive! certainly helps! here's what i think! an int.comb. engine needs a few things..,
- compression (you'v mentioned this! obviously tested by attempting to start with plug in.)
- fuel. again,coverd, no dramas.
- spark. perfect spark!

ok. what about timing? has the timing key sheered or something, thus causing the thing to fire to early/late and cause no start. seems if it just sort of happened out of the blue, it would be likely thats something of this nature has resulted...? just a thought.

Alternatively, how about the exhaust. is it free for emissions to pass ? gotta be something like that. i tell ya! what about a hairline crack around the spark plug opening up when the sparkplug is seated tightly?


let us know how ya go?good luck!!