1978 GS550 Idles for 5 seconds then dies

[timebombprod]

Fixed!!

I got a 5/16 line and drained all the gas from the system including the carbs. Was still running only two cylinders until i pulled the spark plugs and saw that cylinder 3 was fouled pretty bad. After replacing it started to idle on 3 cylinders and when it got to temperature cylinder 4 actually started firing even though it wasnt when it was cold. I believe the compression at cold temps is too low on that cylinder but on higher temps its enough to ignite the fuel. Took it to the gas station and for a half an hour ride and it runs pretty damn well for a 42 year old bike that definitely has seen better days. Thanks for all your guys help on this problem. Youll probably see a post in the electric section about a bad turn signal circuit here soon.

- Joe

Check your spark plug cap resistance and cut a quarter inch off the coil pack wires when you retwist them, that may help

[joeman001]

Hi Ian,

Not sure what you are referring to? Are you talking about it not running on one cylinder when its cold or the turn signal circuit? One of the pins is actually cracked on the 2 pin relay or whatever it is so im going to find a replacement.

Thanks, Joe

[cowboyup3371]

Joe,

He's referring to the spark plug wires themselves. You can unscrew the boot from the wire, snip off about a 1/4" of the wire then screw the boot back on to help clean them up.

When you said you drained the fuel, did you actually do an oil change and replace the oil filter as well? If not, please do that ASAP so you don't risk killing that engine.

I'll respond to the PM shortly as there is much more work you will want to do to it but glad it started and ran

[timebombprod]

Hi Ian,

Not sure what you are referring to? Are you talking about it not running on one cylinder when its cold or the turn signal circuit? One of the pins is actually cracked on the 2 pin relay or whatever it is so im going to find a replacement.

Thanks, Joe

What connects to the spark plugs are called spark plug caps, they wear out over time due to heat, you want to check their resistance and it should be around 5, the wires connected the caps are what i called coilpack wires, maybe not the best term not sure, but cutting a quarter inch off of those wires will give you some fresher wire making a better connection. Might help you out.