Yamaha DT125E 1978 2-stroke Starting Trouble
Bit of a project bike. I had it starting when I first bought it, before I stripped it down and repainted the chassis, cleaned the engine, replaced the carb and the spark plug. I'm running premium 98 unleaded premixed with synthetic 2 stroke oil at 32:1, as the auto-lube system is currently under maintenance (project for a later date). It's a kick start bike with points ignition and should be able to start without battery, which is what I currently have it wired up as.
When I kick it over it runs for about 3-5 seconds before the engine just dies, and if I check the spark after this it's usually tan and very slightly wet. After kicking it over a couple more times it'll run for another 2 seconds before dying again. After a couple more attempts the plug comes out wet and black, which all wipes off. The carburetor float height is set to standard for this bike, the jetting needles seem to be the right size (identical to the old carb that was on it), I've cleaned it multiple times, all the jets are free. Fuel flows freely from the petcock valve through a filter into the carb and stops when the bowl is full. Airscrew is set about 1 1/2 turns out. I can start it cold without the choke on, and when I do turn the choke on it seems to accelerate my wet spark plug symptom. The hole in the carb for the oil which should be pumped by the autolube system is capped off. Compression is good. Exhaust is clear. Airfilter is oiled. Spark plug sparks blue outside engine every kick.
I am quite baffled by this and cannot seem to find a solution, any suggestions or questions would be much appreciated!