Suzuki 2 Strokes

Hi everyone,

I’ve spent the last 12 months restoring a 1975 GT250M.
I’ve had the top end done, crank done, along with about 100 other things!

I’m just at the point where I can’t get her running properly. When the bike is on its side stand, the revs will increase, when upright, it will struggle a bit, and leant to the right it will die immediately.
Also, when up right, if I rock the bike back and forth it will die also.

My timing is spot on, my fuel tap is clear and flowing well, new spark plugs etc. I’ve stripped and rebuilt the carbs numerous times now, new internals, ultrasonically cleaned, my floats aren’t getting stuck, my float height is set to 13.6mm.
The throttle cable is not the cause, I disconnected it to rule it out. I’ve also tried moving wiring about whilst running to see if a broken wire was the cause, no change.

The condition is not effected whether the choke is on/off, and the the fuel tap position does not impact it either.


Any help/suggestions would be greatly appreciated, I’ve exhausted all of my knowledge trying to get this right!

which wiring have you tried moving about? have you looked inside the headlamp shell at the 4 pin connector to the ignition switch? or the 2 wires to the kill switch? very easy to dislodge connectors when putting the headlamp rim back on, as i know from experience. have you checked the coils? could one of your ht leads [or both] have come loose? the engine dying when rocking the bike backwards and forwards makes me think electrical connector loose somewhere and only just touching at times. try these suggestions and get back to us with the results
cheers, dd.
p.s. it's got to be something simple

Thanks for the response Dolly!
I removed my headlight so get a clear look, the connectors seemed okay to me but obviously they’re a bit old. I’ll try replacing the connectors for the kill switch tomorrow and give everything another clean.
HT leads are all good, I think the wiring is the only part I haven’t gone through with a fine tooth comb whilst trying to get it running properly.
It just seemed so much like a carb issue I may have had my sights in the wrong place.
And cheers for the reassurance, I’ll keep you posted

The twins have a tendency to run on only one cylinder when the electrical system is weak.

Start with a fully charged battery in good nick. Run temporary wires directly from battery + to the coil wiring connector.
Check voltages & voltage drops for coil & points when the left points are open. Repeat when the right points are open.

If some numbers don’t look correct or are not balanced, then you found some problems to fix.
If the numbers look good. Start it up & see if you still have that left-right lean problem.

Also , the battery IS the voltage regulator. Remove the fuse when doing the above so you don’t accidentally burn out some of the lights.