Hi, I'm new to the forum, I purchased a smc 250 a week ago as a 'none runner'. With a few basic steps inc cleaning carb (worst iv ever seen!) and charging the battery I managed to get her breathing again. I was made up as I got the machine at a very good price. However.... She fires great even off a cold start, and revs up normally, but It only revs to about 3000rpm (guesstimate, no rev count) and sits there. There is no spluttering or backfire just sits there as if it has a rev limiter. Iv pulled plugs from each head (it's a twin) to see if boTh cylinders are firing which they both are. Does anyone have any ideas? Iv spoken to a couple of lads who think it's some sort of safety relay.... Basically the bike thinks it's in neutral and won't Rev past this rpm?? Iv checked oil level and it's on half way (not serviced her yet until I know the engine is sweet and won't spend money either until I know) can this cause this? Iv been told defiantly not... Any help would be much appreciated, and if anyone has had experience of this I'd be over the moon. It's being used solely as a off road quad l

Thanks

 

Just to clarify I pulled the spark plug caps off the plugs alternatively while it was running just to be politically correct lol!

 

Anyone??

 

Without a manual or wiring diagram all people can do is guess. Yes a safety switch/neutral switch problem could cause limiting along with a limiter module itself if it has one.