misfire/flatspot & intermittent running on 3

[nige]

hello, first time i've used the forum but i'm really lost. short history of my problem.Bought 1976 z900 A4 been stood for 11yrs .Got it going eventually but couldn't get it running nice ,rich&sooty missing on various cyl . Rebuilt whole bike etc. keystercarb set,dyna s ign ultra-sonic carbs, but not touched engine as seems ok only 16500 mls.plugs now burning about right but still running rough 3500/4500 revs & sometimes starts on 4 ok ,next time on 3 [no 1 mianly].Tried loads different settings with carbs nothing seems to solve it . Only other possibility could be coils ? also fitted exhaustcraft 4-1. Sorry if i'm rambling on.Anybody help ! nige

[Mark Tiller]

All my previous Zeds were a bit reluctant on no 1 when starting from cold or from being stood for a while but that was only for 2-3 secs.

the flatspot you mention however i think could be coils/leads, but if you coud borrow another set of carbs to bolt on to eliminate those as the cleaning of all those passageways inside is tricky, one of my previous Zeds had sat for seven years and was all gummed up

[Rich]

check valve clearance
check compression
check voltage to coils
check emulsion tube holes

[z1bman]

swap no 1 plug cap over to no 4 ?
have you checked check valve clearance ?
******************* compression ?
******************* inlet rubbers for leaking air ?
******************* fuel level ?
are all the holes clear in the emulsifying tubes ?

i would recommend using a good quality fuel injection additive in the tank for the first couple of thousand miles or you can use it permanently

[Mark Tiller]

i would recommend using a good quality fuel injection additive in the tank for the first couple of thousand miles or you can use it permanently

Never heard of that?? what does it do?

[compo z1r]

i would recommend using a good quality fuel injection additive in the tank for the first couple of thousand miles or you can use it permanently

Never heard of that?? what does it do?

stops things gum'in up also use castrol lead additive back in the 70's we all used leaded fuel and it lasted a lot longer than unleaded and i could'nt give a f*****k about the planet [ quote clarkson ]

[Pigford]

Fit a new set of Denso plugs

[z1bman]

i would recommend using a good quality fuel injection additive in the tank for the first couple of thousand miles or you can use it permanently

Never heard of that?? what does it do?

as compo z1r has previously said prevents gum + if used regular will dissolve anything that has been left behind by ultrasonic cleaning

[nige]

thanks everyone ,its given me a few more things to try. I think i'll look at the engine department first as its not been checked,compression, valves, etc,& get coils checked. cheers lads