I put a 1987 250 fourtrax motor in my 1985 250sx frame recently, with the fourtrax wiring harness, the motor was running perfect, would go first kick and idle fine after warming up for a minute, drove it a fair bit over the past week and never had a hitch. Yesterday i took it out of the shed and it took a few kicks to get going then when it did it cut out, then finally i got it going and started driving it and i was holding the throttle still but she would catch and speed up for a second, then lose power and almost die then rev high and take off again, it did this for about 100ft then cut out, after that i could get her going and she would idle for a bit until i put it in gear or shook the bike (making me think electrical rather than fuel). Does anyone have any idea what this could be?.. before i end up taking it to a shop and dishing out a pile of money.. Thanks a million

 

Check harness ground or charging system

 

just found my pulse generator unplugged, was probably loose when it was back and forth the other day and came completely apart somewhere between there and me getting her home