Please help with this mystery.

[Guest]

My cafe is nearly complete, but here's the problem. One cylinder is not working, if just pops and bangs. It's got a spark, fuel, air and compression and all combinations of the above and it will not work. It ticks over nicely and you can remove the plug cap and it makes no difference what so ever. Remove any of the 3 others and the engine falters as it should. Help, any answers or ideas?

[GSX1000E]

You made certain to have it running fine BEFORE you decided to improve the looks, right?

[Markyd]

Yep, was running fine and smooth, ticks over lovely.

[hampshirehog]

Try swapping the plug lead with its twin. If it's still faltering on the same cylinder try swapping the plugs.

[Markyd]

I will get back to you, if it still falters what would be your thoughts? Thank you for your thoughts.

[hampshirehog]

More than likely a carb issue if nothing changes but have you also checked your valve clearances?

[Markyd]

Makes no difference, leads swapped and plug, no improvement.

[hampshirehog]

Have you checked your valve clearances?

[Markyd]

All valve clearances/shims done.

[tom203]

Since it pops and bangs, maybe this carb is way out of sync with others and not delivering mixture.

[chuck hahn]

First idea is for you to click on SETTINGS at the top and then EDIT SIGNATURE and fill in the blanks. My crystal balls good but it needs a few clues to what bike, what style carbs..CV or VMs to even venture some helpful tips.

But by the way it sounds to me they are CV carbs and the butterfly on that carbs not open far enough. If they are CV carbs, loosen the adjuster jamming nut between the carbs and turn the adjuster screw a little to see if it lights off.

[Markyd]

I have added some info, thanks for help, the bike has CV carbs.

[Markyd]

Butterfly is fine, all checked so it's not the cause.

[hampshirehog]

Is the plug on the duff cylinder getting wet?

[chuck hahn]

The butterflies may be "open" but are they open enough was my point. You can bench sync them and have a sliver between the bottom and the carb body that looks like it enough and buts not. Little more open and it light right off. Had a guy a few months ago that had this problem. He adjusted the screw with the bike running and it settled the situation.