bagonails

It's ali - on close inspection it appears to have some sort of tank seal lining that is breaking up and has a sticky residue on it - maybe this is the cause??.

The rings are getting stuck and are not moving freely, I've also noticed when I look through the inlet port that the cylinder liner has quite a large lip showing around the edges of the opening - that can't be helping the flow of fuel! When it's cleaned up and all back together I'll try to use it more aggressively to stop the build up and mix the fuel a bit leaner. Thanks for the advice.

I have just purchased a Bultaco Sherpa T 250 with a view to dabbling in twinshock trials. Never really had a two stroke off-roader before - I'm more into brit bikes (A10 & 6T), but I've always liked the trials scene and have attended a few local events as a spectator - in fact the first one I went to a few years back had Sammy Miller as one of the course stewards (scary). Love the content of the various Trials Central forums, it's like having an extra workshop manual in your toolbox!

Has anyone seen this before... When I start my newly acquired 198 Sherpa 250 (pig to start) the throttle sticks on three quarter throttle until the engine warms up, then it's fine - ticks over nicely. I decided to investigate and noticed the carb slide on the intake side has a circle of sticky black goo on it (presumably becomes less sticky when warm). I then went further and removed the head and barrel and the same sticky black goo is coating the intake side of the piston. The bike has a tank of fresh fuel mixed at 40:1, so my question is 'what is causing this build-up of oily goo?' Bike has good bore and piston and has been converted to electronic ignition. Any advice appreciated.