49 Iron Head G80 starting problems

[Samuel]

Went to start the G80 after over 6 months standing un-used due to the current situation.

After cleaning the plug and mag points, the engine started but exhibits symptoms of running very lean.
As soon as I reduce the mixture control the engine starts spitting back through the carb.
I am running a 'new' Burlen 289 pre-monoblock with all the standard settings. (Equivalent to original 89B/1AK)

So I removed the carburettor and cleaned all orifices with carb cleaner (including pilot jet) and all seemed OK.
Put it all back and still massive spitting back through carb as soon as I try to reduce choke.

Any further ideas to follow up on this ladies and gentlemen?

[Rob Harknett]

Has the timing slipped so its too far advanced? Or its stuck at the mag fully advanced.

[Samuel]

Has the timing slipped so its too far advanced? Or its stuck at the mag fully advanced.

I'll check that next time I am able to do so. The manual advance / retard is working fine so maybe timing has slipped ...

[Rob Harknett]

Has the timing slipped so its too far advanced? Or its stuck at the mag fully advanced.

I'll check that next time I am able to do so. The manual advance / retard is working fine so maybe timing has slipped ...

Sam, assume you have watched at the mag end, when operating the lever. I have nearly always found spitting back as being a timing fault or air leak at carb / exhaust

[SPRIDDLER]

Went to start the G80 after over 6 months standing un-used ..........the engine started but running very lean.
As soon as I reduce the mixture control the engine starts spitting back.

cleaned all orifices with carb cleaner (including pilot jet) and all seemed OK.
Put it all back and still massive spitting back through carb as soon as I try to reduce choke.

After standing for 6 months and in spite of cleaning the carb it's a pound to a penny that the Pilot jet or drillings still have a (perhaps new) blockage.
Presumably it was running o.k. when you last used it so the timing is unlikely to have slipped whilst not being used.

[Samuel]

Thanks for the responses - the next stage will have to wait until I can travel to Rushden again.
I will report back when I have further news.

[raffles]

Sam have you changed the petrol I have just purchased two bikes that would start and then run all over the place
then not start at all. Drained the tanks cleaned the carbs and now start first time and run beautifully.
Tony

[ajscomboman]

Sam have you changed the petrol I have just purchased two bikes that would start and then run all over the place
then not start at all. Drained the tanks cleaned the carbs and now start first time and run beautifully.
Tony

Bugger you beat me to it Tony! I suspect water in the petrol which is a classic for this ethanol based fuel if it's left for long periods, you get separation and the water being heavier sinks to the bottom of the tank. Just had the same thing happen on a G12. My mower does the same thing, fill with fresh and it'll run like a Swiss watch.

[clive]

Not sure Sam has ever had it running like a Swiss watch but it sounds like a sensible thing to check, relatively easy too

[Duncan]

Sam have you changed the petrol I have just purchased two bikes that would start and then run all over the place
then not start at all. Drained the tanks cleaned the carbs and now start first time and run beautifully.
Tony

Bugger you beat me to it Tony! I suspect water in the petrol which is a classic for this ethanol based fuel if it's left for long periods, you get separation and the water being heavier sinks to the bottom of the tank. Just had the same thing happen on a G12. My mower does the same thing, fill with fresh and it'll run like a Swiss watch.

Unlike your G15 which is more like a cuckoo clock.