Farting and spluttering and backfiring

[andy f]

No, not me the bike 

Afternoon all, after a bit of help diagnosing something please.

I have a 02 plate FZS 600, had it for a good few years and it has never...never let me down. We moved house middle of last year and now no longer have a garage, as I got made redundant at the same time i haven't been using the bike so have now decided to sell her. 


Went to start her the other week and she fired up but farting and spluttering, thought it was just where she isn't garaged anymore and damp had got in.
Pulled all the plugs, cleaned and checked the gaps, and checked the leads, before tightening them all back in checked to see they were all sparking nicely on the engine casing. All looked good. Still farting and spluttering though, By holding the down pipes .....carefully, I decided it was just No 3 cylinder not firing ( as the down pipe wasn't getting hot . Took the plug out again swapped the plug for No 1 tested against the housing all good , Still farting and spluttering.

Now while the bike has been outside I had it on it's side stand so No 3 and 4 side of the engine would have been more open to the elements

So now I'm thinking fuel / carbs. Changed the fuel filter, got some aerosol Carb cleaner and emptied about half a tin into the air intake all good, running niceley. took the bike out for a blast down thee motorway, ,little be stuttery when opening up but after a few miles seemed ok, did about 5 miles on the motorway and came off at the next junction, got down to the roundabout and it stalled, a real pig to start again, popping and back firing, pulling away back onto the motorway was a mare on the way back home on side roads would easily stall as i pulled up at lights etc. got home and No 3 and No 4 down pipes were not hot. Again checked all the plugs and leads and am confident they are fine.

So a bit miffed now I left it until the next weekend, Started up ok, all downpipes warmed up nicely but then again N0 3 stopped heating up, out with the carb cleaner again, and again after after a while she's running nicely again, but the after a quick run spluttering again !!!

SO Sunday i put a load of carb cleaner in...loads, took out for a ride, all good, started her up Monday and out for a ride...all good, left it tuesday and started her up today and she is spluttering again , took her out and she's still not running right. Defo No 3 and 4 cylingers, 1 and 2 are fine which make sense as when it was on the side stand 3 and 4 are open to the elements.

So what's next ? I'm thinking it must be fuel ? I drained the float chamber of No 4 and although it looked ok as it drained it did look a bit cloudy when it was in the plastic tray i emptied it into but i'm thinking was it just the plastic tray I emptied it into. So do I drain the tank and lines, drain the float chambers and put fresh fuel in ?

Any advice much appreciated I think I'm on the right lines


Andy

[matt7chunk]

Sounds to me like you just need to pull the carbs out and give them a good clean (jets and float valve)


And definitely drain the tank if its been sitting for a long time



Also could check the inlet rubbers for a air leak somewhere

[agricola]

Wouldnt do any harm to check the air filter too. Becaise its been stood for months, the fuel will have gone off, so its drain, clean and fill with fresh. If its till playing up, then its carbs off

[andy f]

Thanks for the replies, good to know I was on the right track


Andy

[BBROWN1664]

BAsed on my experience of modern fuels, leave the bike unloved for a few months and you will get gummed up carbs.
They will need to come off and clean the jets