Suzuki GT250M, only idles leant to the left?

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Jgt250
Still in the Driveway
Posts: 2
Joined: Sat May 09, 2020 4:19 am
Country: United Kingdom
Suzuki 2-Strokes: 250 1974

Suzuki GT250M, only idles leant to the left?

Post by Jgt250 »

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!
dollydog
Yeah Man, the Interstate
Posts: 630
Joined: Fri Aug 11, 2017 7:09 am
Country: england
Suzuki 2-Strokes: several gt250 ramairs

Re: Suzuki GT250M, only idles leant to the left?

Post by dollydog »

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 :D
cheers, dd.
p.s. it's got to be something simple :up:
GTS250 road registered. TS250 engine, Ramair frame.
GT250 big bang road registered. Both pistons fire the same time. USD forks.
GT285 road registered. Overbored - 58mm and TS125 +2 pistons fitted.
GT10 road registered. '65 T10 engine, GT250 frame.
Jgt250
Still in the Driveway
Posts: 2
Joined: Sat May 09, 2020 4:19 am
Country: United Kingdom
Suzuki 2-Strokes: 250 1974

Re: Suzuki GT250M, only idles leant to the left?

Post by Jgt250 »

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 :up:
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jabcb
Moto GP
Posts: 4240
Joined: Mon Dec 13, 2010 4:32 pm
Country: USA
Suzuki 2-Strokes: 69 T350 thru 75 GT750
Location: southwestern Pennsylvania

Re: Suzuki GT250M, only idles leant to the left?

Post by jabcb »

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.
BAS (Bike Acquisition Syndrome) - too many bikes but have room for more

Suzuki:
GT750 2x75
GT550 72 & 75
GT380 72
T500 69 project & 73 project
T350 69 & 71
Honda 85 CB650SC & 86 CB700SC
09 Triumph Bonneville SE
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