GS1000 Killing plugs!

[Anonymous]

Hi,

Recently got a replacement engine for my '78 GS1000E. Everything was fine for 25 miles then plugs on 1 and 4 died. Suspected the condensor, (or the coil but condensor was cheaper to replace first!), so I replaced it and added a new set of points. Result was exactly the same but only no.4 plug died, (ran home on 3 and laid plug on top of engine and definately no spark). Put in a new plug and started and ran perfectly for 20 miles then no.4 went to the plug graveyard again.
OK, I thought, its got to be the coil. Swapped the coils for another set and had the same problem, (also ran very rough)!

Does anyone have any ideas that might help me or have even heard of this before?
Please help!
Thanks,

Fraser

[SqDancerLynn1]

Have you changed the plug caps??

[Anonymous]

Sorry, forgot to mention that! Yes, Plug caps were changed too! Thanks

[KEITH KRAUSE]

What do the fouled plugs look like? Dark or black with dry soot...or black and wet with gas...or shiny black and wet with oil? If wet, do the plugs dry themselves after sitting awhile?
Do you have any white smoke coming from the exhaust, especially when still cold?
Do you have any black exhaust when opening the throttle?

[Anonymous]

ok - bit of white smoke at start up but clears when warm - when plugs were removed they were blackish and wet with gas - electrode is dead though, (plug will dry but will not spark again even after leaving to dry and or cleaning)

[Detman101]

Wet plugs = too rich(from my experience)

Could be a number of things. I can think of: Bad o-ring on needle seat....mixture screw tip broken...mixture screw settings too rich...

Hope I helped,
Dm of mD

[gremlin]

if your running ngk spark plugs change them. my gs1000 hates them, for some reason the ngk's will only last a few days.

bosh makes a good plug.

[KEITH KRAUSE]

fwhitehe, your problem plugs are glazing over and the spark is tracking down the insulator instead of jumping the gap. Are you using the right plugs such as NGK B8ES?
Is it possible to check your compression? Since you're burning some oil which is at least helping to foul the plugs, this should be checked first. If you have a couple of cylinders down on compression, combustion will be poor and no amount of tinkering with mixtures will get it right. Were the valve clearances set recently? If your compression is still good and the coils and points are working as you said, then there are some things to check regarding the carbs and fouling plugs.
You did'nt give any info about the carbs. They could be dirty inside or set up wrong or have unmatched jetting...
If you have the stock carbs, some common causes that would foul plugs like you describe: A poor carb synch. If one or two carbs has more vacuum than the others, that carb(s) will run richer.
Float height out of adjustment or a damaged or sticking float. The floats may have to be set and also check the float needle valve for a groove worn into its point or a weak spring. Check the gasket or o-ring for the float valve's seat.
A bad o-ring around the needle jet/bleed pipe. If this o-ring fails, that carb will run rich.
Dirty carbs inside. If the air passages are clogged, you'll run rich.
Loose jets will cause a rich mixture. You may have the wrong size jets or needle jet/jet needle. The needle may be adjusted too rich or be missing the plastic spacer on top the needle e-clip or maybe the two plastic spacers on the needle have been reversed (the thicker one goes on top the clip).
You may have the pilot screws (underneath) set wrong. They are generally 1 to 1 1/2 turns out. If you seat them, do it LIGHTLY.
The side air screws should be about 1 1/2 to 2 turns out. These should be set to achieve the highest idle at normal operating temp', then set the idle correctly with the idle screwknob.