A step away from Wit's End......

[Guest]

This may be my last shot at getting this bike running right, as my patience is nearing the end. I appreciate all the GS'ers here and your patience with me. I've tried all your suggestions so far, and had my bike in and out of the shop for several months. Here's the short version: 1982 GS850L with 12,000 original miles. Stored in my garage past 8 years, and resurrected this year. Dismantled, cleaned and totally rebuilt carbs-by professional Suzuki mechanic-not me!; gas tank & lines in perfect shape; new battery installed; new Dyna S installed. New plugs & general tune-up. Runs strong as hell 70-75-80+ mph with no problems at all;no backfiring, smoking or anything on acceleration or deceleration-I mean PERFECT like new. Normal idle is around 1000-1100 (even though I just turned it up to about 1200 to try and compensate for my problem, but don't think that's the answer). After bike warms up and gets good and hot after 20-25 minutes, soon as I stop, idle drops down to 400 or so, and stalls on acceleration every damn time. Tried turning idle mixture screws out about 1/2 turn to richen mixture, as I was told bike was running lean, with plugs mostly white and dry-no improvement. Weird thing is, at idle, if I pull plug caps off plug #3 or #4, bike shuts off immediately. When I do the same for #1 or #2, no change in idle, no nothing. Only ignition thing left to change are coils, but I'm not sure they're at fault, and tired of dropping $$$$$ by process of elimination. Before I turn this beautiful bike into a fleabay parts bike, does anyone have any other ideas?? Thanks guys. Larry.

[Otto]

Try to change the sparkplug caps. I got an electrician to messure mine, and they where somehow electrical blocked? it was cheap, and i got rit of my spooky ignition. I dont think it is the coils.

[ikazuki]

how strong are your sparks? thick bright blue or skinny white light ?
use your volt meter to check how much voltage you've got in all the important places; ie battery/ regulator rectifier/ ignitor/ alternator/ and yes the coils.
remember that the gs is mechanically bullet-proof. the electric pains we must endure are as a result of old age but can be overcome with better engineered equipment. you are doing just that, you wont have any problems out of the parts you have replaced so hang tough,you'll get it. ikazuki

[Rocketman]

If I hold the sparkplug boots in my hands while the engine is running, I get sparks running up my arms. Is that normal? P.S. I'm NOT touching the bike with my other hand while doing this. It sure feels like I'm only idling on 2 cylinders, but running flat out on all 4. That's what makes me think the problem is ignition related, cause when I pull one plug cap off, the bike theoretically should run OK on 3 cylinders, but since its shutting off, its really probably running on 2, which is not enough to keep it going. What in the hell makes a bike drop two cylinders at idle (especially just cylinders 1 & 2 dropping out), and run strong on throttle?

[ikazuki]

the spark is seeking a ground. when plugged onto the sparkplug, the engine conducts the ground to the frame and thus to the tires and then to the "ground". so yes it is normal for you to feel an electrical shock when you pull the plug wire off of the plug. what surprises me is that you didnt get a big enough jolt for you to comment on. ikazuki

[Rocketman]

I wish the jolt was large enough to knock me on my ass and end this misery of having a beautiful classic bike, which I can't get to keep a steady idle. What a pain in the butt;the perfect love-hate-relationship. I wish there was one concensus and one answer to make this work. Is it worth rebuilding the entire carbs again, in the hopes that there might be some microscopic piece of crap clogging the jet in Carb # 1 or #2, which at idle is closing off the jet, but at full throttle the vacuum is strong enough to offset this issue????Since I can only get to bowls #1 & #4 while its still on the bike, and I have to remove the tank and airbox (freakin' again), I can't even clean the carbs out without removing the whole thing again.....oh man, how do I really know if its carbs, ignition, or sunspots from Mars?

[tconroy]

I wish the jolt was large enough to knock me on my ass and end this misery of having a beautiful classic bike, which I can't get to keep a steady idle. What a pain in the butt;the perfect love-hate-relationship. I wish there was one concensus and one answer to make this work. Is it worth rebuilding the entire carbs again, in the hopes that there might be some microscopic piece of crap clogging the jet in Carb # 1 or #2, which at idle is closing off the jet, but at full throttle the vacuum is strong enough to offset this issue????Since I can only get to bowls #1 & #4 while its still on the bike, and I have to remove the tank and airbox (freakin' again), I can't even clean the carbs out without removing the whole thing again.....oh man, how do I really know if its carbs, ignition, or sunspots from Mars?

You have new plugs and a clean air filter? Just a thought.

[Rocketman]

Yes brand new NGK plugs gapped perfect installed with the overall tune up less than a month ago, and brand new oiled stock spongey air cleaner wrapped with the original basket-like air cleaner skeleton. No air leaks from air box, side covers, boots, intake or anywhere (except my wallet!)

[Nessism]

Can you try switching the coils around to see if the problem follows? I've also had problem with spark plug caps so they are worth checking into.

[Rocketman]

Since coil #1 controls plugs 1&4, and coil #2 controls plugs 2&3, I don't reallly think the coils are bad, although I really appreciate the thought. It seems like only at idle, cylinders 1 & 2 are dead or really weak, which would eliminate bad coils, because then 3&4 would be dead too, and nothing would be running. I even swapped plug wires for #1 & #4, and same result. Pulling cap off 1 or 2 made no change in engine idle; pulling caps off #3 or #4, shut off bike. Would this be an appropriate time to ask wtf, or should I wait a bit longer?

[Arie]

I am going to venture a guess, as I have had electrical gremlins that had behaved in a similar manner: ok cool, demonic when hot.

Some electrical connectors , especially those with corrosion and/or loose fitting ones, have more resistance, and thus generate heat. This heat exacerbates the situation, making an even worse electrical contact.

I would bet dollars to doughnuts that you have loose / bad connections to the coils, and correcting them will solve the problem. I suggest starting with the spade clips that go to each coil. remove one at a time, clean male terminal, examine & clean female terminal, squeeze female terminal with pliers, shoot with connection cleaner, reinstall, repeat on all 4.

also check the leads that come from the fuse box and go to the coils - or/wht i believe, same as above.

hth

ps, fix yer bike - lets ride!!

[Rocketman]

I'm working on it Arie. What a pain in the butt this is going to be. Removing and draining the tank to clean coil connections. But guess its better than spending my days complaining rather than riding. Tarbash in Centereach says he's a pretty good GS mechanic, and thinks he might be able to help during the week. Just not sure if I should go back to Chuck Wagon Racing on Tuesday, to see if he can figure this out-since he thought just changing idle mixture screws & installing Dyna S would do the trick. Maybe some fresh eyes & hands is a better idea. What do you think?

[chef1366]

Earl had a similar issue with a new dyno. I'd ask him how he fixed it up.

[Arie]

fwiw,

when I remove my gas tank, i just pull the two gas lines and it does not leak.

This gives acces to the stuff below.

[Rocketman]

By the way Arie, what's your opinion of the pulling the spark plug cap thing I discussed and the spark up my arm discussion above in technical area-see "Wit's end". Thanks.