left hand crank seal is a strong contender try spraying WD40 at it through the gaps in the magneto rotor, may seal it enough to start or to prove failure here
Greetings Mike
its 'Air Injection System' for emissions, allows air from the airbox into the exhaust to enable further combustion, so presumably thats the way of flow...from aibox to exhaust.
PM me your email if you want a PDF manual
What brit iron have you got
Good stuff NEO, bear in mind that mine came back with slightly wrong offset so i loosened all the spokes one side then tightened all the other side the same amount....both wheels, no bother though
the primer was 'ambersil zinc primer'
buy a few more spark plugs miles and try them, after a winter layoff my DTR wouldnt start, but it did with a new plug...then i put the original plug in and it continued to run ok...as the americans might say...'go figure' !
All valid points, the brakes, the fitting of a physically bigger engine, the bigger carb etc...no room to connect to the airbox, making a new exhaust..blah blah!
just not worth the headache
nahh dont run without it, it will make one hell of a racket and possibly perform worse...and with two strokes its not good for the engine.
Take off the exhaust and see if the header pipe is reduced in diameter at the neck of has any washer like restrictions in there, I wouldnt advise doing any more than that with your rare bike.
whats this
http://www.ebay.co.uk/itm/yamaha-dt125-lc-1985-oil-tank-water-bottle-other-parts-available-/260912258688?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item3cbf951e80