I am at my wits end with an ongoing problem with my 1981 RM125X. About 10 months ago it started missing & coughing etc when it was on the pipe.
I checked the stator coils resistance and one of them was not quite the book figure so I bought a second hand (almost new) stator on ebay it was originally bought from RM Stator is the US.
The bike ran good for a couple of races and then the problem came back.
In desperation I bought a NOS ignition coil and the bike ran OK for a couple of races then the problem came back.
I replaced all of the jets and needle/airscrew etc in the carby and reset the float height and the bike ran great for a little while then the problem came back.
Over the off season I had it rebored and fitted a wiseco piston, it ran well for a while then same thing again.
At one point earlier this year the bike would only run at flat out revs, it would cough and splutter down low so whilst ringing it's neck in a race I seized the big end.
I replaced the big/little end brg's, conrod, all the gearbox & crank seals & bearings and it ran OK for a little while then the problem came back again.
I then replaced the main 250 jet with a 270 jet as the latest problem was again at high revs and seemed to improve a bit when I raised the needle. After that the bike ran great for a little while and then the problem came back, this time it would cough & splutter and backfire at low revs to the point where it would not idle and then stall.
When I checked the spark it was weak and inconsistent so in a further desperate measure I bought a second hand CDI, bolted it on got a good strong consistent spark and the bike ran well for about an hour and a half and then started to break down high revs then would splutter and stall at low revs. Now it has a weak and inconsistent spark again.
I would love to put a match to it but I have spent too much money and time to let it beat me and when it runs well it goes like stink!!
Any of you Suzuki tech heads have any ideas? Pllleeeaasssee.