Chris, I own enough of these Vintage Sweedish things to tell you that these Sweedish bikes can be fair b****s of things with the two stroke motors. Mate, they can be like that leggy blond that broke your heart in high school. They can be difficult to get, hard to get started, impossible to keep going and can go through all your hard earned savings. They can be as temperamental and contentious as all hell and most have have borderline personality disorders. My advice mate is to slowly collect the original parts, but this will take most of the rest of your lifetime, but by then you ought to be able to sell the "original" item to some nutter collector of these things. The collecting will cost you many hours, days and years of wasted time, but in the meantime keep the non original motor in the thing, save to say, try to make it a 250cc four stroke if you can. It will be like comparing your girlfriend from next door to some fashion model. Mate they never a good ride if you have to waste hours and spend lots of time and money getting them to like you. Good luck mate.