A strange backfiring issue........

[solidstate100]

Hi all

Not sure about this one.... for the last few cold starts of the day the G/S is either difficult to start, needs milling over for a good 4 or 5 attemps of up to 10 secs each, which then culminantes in a big old backfire (thru the exhaust, not the air intake/carbs) then will start and run as normal in all regards OR will occasionaly start as normal (first push of the button, full choke, throttle partly open) run for a minute during warm up then suddely just die, then will need milling over as above, backfires (I tell you my ears are still ringing) then away we go as normal........Any ideas?

This has manifested itself in the last week, prior to that all was perfect, am on top of all maintenace items etc so something tells me something is starting to fail (Hall sensor? Ignition module? something else leccy? Advance mech? maybe fuel related?) and the bastard is going to leave me stranded somewhere, so before I rip into it, any ideas or experience anyone??

 

[Kenny]

My money is on the bean can !

 

[B Murr]

Sounds electrical to me, the backfire being the unburnt fuel that's built up in the exhaust being lit by the first hot flame coming from exhaust valve when it does initially get a good spark and ignites mixture in barrel. So something electrical that applies to both cylinders.

 

[duckspeed]

Kill switch? Side stand switch? Water in ignition switch?

 

[ChasF]

Either ignition coil or bean can but could equally be a dodgy connector. If it does it again try flicking the kill switch a few times to see if that changs anything.

 

[Beemerboff]

My G/S had the same problem.
Fault was in the ignition switch - the black plastic back of the switch which looks to be crimped in has slackened off on the crimps and was moving around enough to loose contact occasionally.

 

[solidstate100]

My G/S had the same problem.
Fault was in the ignition switch - the black plastic back of the switch which looks to be crimped in has slackened off on the crimps and was moving around enough to loose contact occasionally.

I think you may have hit the nail on the head with this - many thanks!

I did all the usual visual connection checks and traced varous wires to check for damage etc and hey presto, yanked the headlight cover off and the base of the ignition switch was a bit loose in its crimps. A bit of brute force with some longnose pliers squeezing it back together and all seems to be back to normal, at least for the minute.

Many thanks to all other contributors, Beemerboff next time you are passing the Isle of Wight a beer is waiting