1 cylinder firing Troubleshooting

[Gman]

If the bike is only firing on 1 cylinder here's a quick way to try and track down the problem/s.
If the problem changes to the opposite side you have narrowed it down.
Do them one at a time.

1:Swap plugs.
2:Swap Plug caps.
3:Swap coils.

If none of these help check the Pink and Yellow leads under the seat and their connectors.The Yellow is for the left coil,the Pink is for the Right coil.

If still no go then suspect the carbs or if really unlucky the CDI unit if this is a CDI powered ignition.Clean all connecting blocks under the seat anyway with Isopropanol Switch cleaner which you can get from Electrical suppliers/Autozone/Maplins/Radio shack.The make ends can be cleaned with a bit of scotchbrite and the females with same but pushed in with small screwdriver and cleaner then wiped with a cotton bud and re-sprayed with Switch cleaner.

[dcadon]

Ok.. here is another one that I came across. The bike only fires on one cylinder when starting cold. Once it gets going...everything seems normal.

How about this... (why I didn't catch it right away, I'll never know)

An almost unperceptable drip from the carb float bowl (through drain screw/and waste tube to under the bike), on one side only. The drain screw - not quite secure. Effect: overnight the float bowl drys up on one side only. Starting is a bitch on one cylinder, until that float bowl is back to full function, then no symptoms.

Tightening up that drain screw, and the problem has been resolved.

[I'm going to GL]

On transistor ignition bikes, you can add 'Swap TI units' to the list.

[Weevee47]

Mine has just started this, starts ok on two, idles on two, pulls away on two then as the revs go up a little (no revcounter) it cuts out on the left pot. Keep giving it throttle and it eventually comes back onto two when the revs are pretty high. Sometimes it sounds like it is eight-stroking at mid revs. So far I've changed the plug, checked the pilot jet is clear and shouted at it. I'm not sure if it is spitting through the carb, but the air filter on that carb was most of the way off after a half mile trial. The end of the exhaust looks wet with petrol/carbon mix. Tomorrow I'll check the valve clearances, try another plug lead and cap and maybe even a coil to see if that helps. It ran perfectly until after it's big oil leak coming home from a mate's funeral last year. Washed the oil off it next day and when I fired it up to go back in the lockup, it only ran on the right hand pot. I put it down to water getting down the plug hole or something like that but when it was first fired up this year, about two weeks ago, this trouble became evident. Any ideas guys, before I slash my wrists?

[Gman]

1st quick thing to try is some WD40/Carb Brake cleaner or similar through the Air-box into the carbs whilst running with the Air filter out.Rev the engine and let it flush though.You can also,with the fuel tap off,squirt some WD40 or carb into the carb fuel pipe and then start up and rev.
You might just have some grit in the carbs affecting the floats.

[silverwing]

Try this one then bikes goes for about 70 miles no problen then all of a sudden starts fireing on 1 cylinder, then goes all ok ride for another 35 miles then starts to fire on 1 cylinder again, leave for about 5 mins then rides all ok for a futher 70 odd miles through london with hot conditions and mojor traffic still ok (whats the problem).

Dave

[Gman]

Could be a coil breakdown caused by heat or bad spark plug cap.If this is a CDI ignition click here,

viewtopic.php?f=10&t=335

I've been running these for a couple or years or more,no problems

[silverwing]

Hi its a gl500 silverwing ti engine any advice greatly appreciated.

Dave

[Gman]

Could still be coils but you need different coils with the TI engines.Also I had trouble with the 30 year old main use holder so replace if you haven't already as per,

viewtopic.php?f=8&t=27

Also one time my carbs got some crud let through the inline filter and that caused problems when the engine got warm

Also make sure the vent hole in the filler cap is not blocked as these engines do not like any fuel starvation.