Suzuki GN250 Starting Problems

[guest1406]

Hi all,

At the stage of the build where getting it running right is needed. However it just wont start. I've tried all the basics, followed all the troubleshooting guides and steps and still nothing. I have had it running and even drove it about 200 meters, there's a big fat blue spark and the plug is slightly wet so there's spark and fuel. I'm really stumped and really stressed!

Starter motor spins fine and the engine spins fine but just no ignition! I've had my mechanic friend over and hes stumped

Thanks for any help guys

[Propellor]

Hi sorry to hear you're having bother. Very frustrating, especially as you seem to have the two main ingredients-petrol and a spark.

The spark needs to occur at the right time though and the fuel needs to be in the right ratio to air.
There needs to be compression too.

Just a thought (or three)!

[johnr]

if its been rebuilt, have you checked the valve timing? you only need to have it one tooth out and it will never ever run.even if its sparking at the right place, if a valve is slightly open when it should be shut, its just not going to run.

[iansoady]

Sure you haven't timed the ignition 180 degrees out?

[guest1406]

Thanks for the replies.

I've checked the valve clearances and they're fine.

I've had it running so surely the timing must be right or near? I'll check again today and see if I can make anything happen.

Cheers,

Mackenzie

[iansoady]

I've had it running

Ah, I missed that.

[guest1406]

The ignition timing is automatic on the CDI? I've looked in the manual and it doesn't say how to correctly time thee ignition, or maybe I'm missing it?

Mackenzie

[johnr]

has the engine been apart at all since it last ran?

[guest1406]

Since the last update on this bike ive done a bit of research and what not into ignitions.

I saw online that someones  woodruff key had sheared and that messed up their timing. I took the magneto cover off and there was so filings or debris so i guess its not that, although when i get the flywheel puller back ill take it off anyway just to make sure for wear.

I did notice that the raised notch on the magneto (where the pick up makes contact) was slightly mushroomed over. Surely it shouldn't mushroom over as only minimal or a gap is needed for the pick up to pick up? So im thinking the gap is too big and misfiring ignition

Cheers for any input

Mackenzie

[guest1406]

Since this post I replaced the woodruff key and magneto rotor. I also had the carb stripped, ultrasonic cleaned, new internals, all reset specs, vapour blasted and rebuilt. Its spot on.

Put the two on and started straight away, idle and everything! It was a bit boggy so ill need to rejet it but it has got a ramair pod filter on it and a built exhaust.

Also a bit of a whizzing sound around the starter motor and the gear behind the magneto rotor. So that's got to come off and be investigated

Mackenzie