One Plug Fouling?

treybrad · October 04, 2004, 10:54:48 AM

So, my bike has been running great for the past 100 miles since I got it running, but yesterday on the way to work it started kinda bucking and sputtering a little. As soon as it started doing it I thought, crap... one of the cylinders isn't firing, must be the oil that was on the plug when I pulled it to replace them.

So today I rode around a little, still doing it, so I hit the kill switch and pulled the plugs fully expecting one of them to be covered in oil from a messed up ring or something. The brake side looks exactly like the "normal" plug on the Haynes chart (Thanks Kerry!). The clutch side looks just like the "carbon fouling' picture... What does that mean? It says i'm overly rich, but... the carbs are tied together, how could one be rich and the other just fine? Is it possible that when it was laying on it's side, maybe for a couple days (:x ugh, careless prev. owner..), that oil got into places it's not supposed to be, and now it's being burnt off and fouling that plug??? I haven't been riding 'hard' really, shifting around 7k, only been above it maybe 5-6 times to play a bit.

I really don't know where to start... :dunno: would love some good pointers..

trey

Jenerator · October 04, 2004, 11:31:30 AM

I went through the same thing recently, and we think it may be that the left carb didn't come fully clean when we brought the bike back from the dead. Just out of the blue one day, I started her up and it wouldn't idle at all. Silly me, I just figured it was taking longer than usual to warm up, and I gently went on my way. It would bog when I twisted the throttle, and stalled at every stoplight. Whatta pain!!

I made it to where my dad worked, and he and his buddy took a look at it. He could hear that it was only firing on one cylinder, so we looked at the plugs - they matched yours exactly. I managed to borrow a plug from someone just around the corner at the local Monday night meeting place and it ran better. I got it home and checked the plugs again after riding it for a bit, and the left plug was again blackening, but was still working. My honey said to swap the plugs (left to right; right to left) and that seemed to clear up the problem somewhat. Now the left side is becoming a tan colour and the right side is normal again. I swapped them once more for good measure and bought a backup pair for the tank bag. No problems since, other than running out of gas. :lol:

Try swapping your plugs - just don't do it if the engine's warm/hot. Check them again after a tank of gas or so and see what colour they are.

The Buddha · October 04, 2004, 12:39:29 PM

OK 100 miles... possibly a sticking float... I sprayed it with wd40 and I probably didn't see them stick... WD40 sorta is the enemy of sticking... Maybe now that the wd 40 is gone... it is sticking.
Cool.
Srinath.

sprint_9 · October 04, 2004, 01:29:32 PM

Ive got the same problem, mine miss fires every so often and I have fouled one plug through out 2 years of having the bike, hopefully this winter when I tear it town Ill be able to figure out the problem.

Kerry · October 04, 2004, 01:41:53 PM

Quote from: treybradthe carbs are tied together, how could one be rich and the other just fine?

This is VERY possible. Both carbs have access to the same airflow through the filter, but air is only one half of the equation. The other half is fuel. Fuel flow can differ between the carbs for several reasons:

perfect (what is?) but I don't think fuel flow is your problem.

Quote from: treybradIs it possible that when it was laying on it's side, maybe for a couple days (:x ugh, careless prev. owner..), that oil got into places it's not supposed to be, and now it's being burnt off and fouling that plug???

After 100 miles of running well? No, I doubt it.

I'm with Jenerator. I think it's a problem with the spark itself. From your description, your plugs look exactly like mine did a couple years ago. My Yellow '99 was down for 5 months of occasional troubleshooting because of a bad electrical connection that prevented one of the Pulse generator coils from working right. I wouldn't jump to the conclusion that your problem is in the same circuitry, but if you get desperate you can read through the Narrowing down the problems to a broken bike thread.

treybrad · October 05, 2004, 05:19:03 PM

Ok, thanks for the list of things to look at. I'll start by taking a look at the carbs, see if a float is sticking, make sure all the gaskets are there. After that i'll start on the list of electrical stuff from that other thread.. I'll let you know what turns up..

trey

treybrad · October 05, 2004, 05:54:50 PM

Ok, fakeout. I went ahead and pulled one plug at a time since it was nice and dark out. I used a spare plug and actually just pulled the wires on each side, one at a time, and plugged the spare plug in... On both sides I get a pretty, blue, intense spark. Either way, they both match on each side. Bike runs the same more or less with either plug wire pulled.. crappy. It isn't warmed up, so yeah. It wouldn't idle or anything.

If I can see such a nice, even spark, does that narrow it down that it's most likely my carbs or some fuel issue somewhere? I would assume if there was such a discrepancy between the spark on each side, I would notice a more yellowish/dull spark...

Are my assumptions correct, or will it still *look* like it's sparking well even if it isn't...?

trey

Kerry · October 05, 2004, 09:09:15 PM

Quote from: treybradAre my assumptions correct, or will it still *look* like it's sparking well even if it isn't...?

I'm not sure I ever ran my bike in the dark when she was down for troubleshooting, so my perception may have been affected, but here's what I remember:

in line with the plug (so the spark would have to jump TWO gaps) and it sparked along just fine.[/list:u]

That's one of the reasons that I had such a hard time tracking down the problem. Everything SEEMED to be OK. :dunno:

At the time I had two GS500Es. I swapped carbs, swapped ignition boxes, and swapped spark coils and wires. Nothing did the trick until I finally tested that corroded connector....

Again, I don't want to send you on a dead end goose chase. But if you have a meter and can follow a wire through connectors, the electrical tests are pretty quick and easy. (A whole lot easier than pulling carbs!)

treybrad · October 07, 2004, 12:30:04 PM

Ok.. How about this. In my continued ignoring of the problem i've run through a tank of gas. I thought it odd when my reserve had to be used @ 115mi and turns out I only got ~40mpg out of the tank. From what I read, that really sucks for a GS. I filled it up the same exact way, getting rid of bubbles and everything.

Is the horrible gas mileage an indication my problem probably lie w/ getting too much fuel? I know, I know, take the stupid carbs off and have a look.. I will probably later today. Still, if that's for sure my problem, it'd be nice to know to give them a thorough look at...

trey

Kerry · October 07, 2004, 12:39:50 PM

Quote from: treybradIs the horrible gas mileage an indication my problem probably lie w/ getting too much fuel? I know, I know, take the stupid carbs off and have a look..

If you have a length of the right-sized tubing, check the float height with the bike on the center stand. I'm not saying that you'll find anything out-of-whack, but if the float height IS off you can know that before removing ANY parts from the bike.

treybrad · October 07, 2004, 01:12:18 PM

well, just tried that, all seems well. gotta run a few errands and commence tearing it apart after that...

trey

treybrad · October 07, 2004, 05:10:00 PM

Well, finallly got off my lazy bum and got to the carbs. Took off the tank and just messed w/ them from there, seeing as how half the trouble of taking the carbs off is getting them back in the little boots for the intakes.

Took off the top hats so I could mess w/ the floats and what not. It didn't *seem* to be sticking, but i'm pretty sure it must have been (Srinath wins the prize). I gave everything a good squirt of WD40 and hoped it would be better. Made sure all my gaskets were there, and that the rubber diaphram thing wasn't pinched somehow. Went ahead and checked my primary and secondary coil windings and everything was a-ok as well.

So I put it all back together and go for a ride. Seems much better, but it always seems a lot better when I put in a new plug. Rode around ~4mi and came back. I knew she felt better b/c the idle was ~500rpms up from last time I rode. Pulled the plug and sure enough, nice and tan.. just the way we like it.

So, luckliy it wasn't an electrical gremlin to track down :mrgreen:, and I got the problem fixed, but is it going to do it again? What would make the float stick like that? Everything is super clean, no rough edges or anything. Should I just hope it's a one time anomaly and move on, or look into something while I'm here? I'd hate to get on a long trip one day and it stick on me again...

Anyway, that's my conclusion.. nothing's worse than searching for a post, finding one that matches your exact problems, and then no one ever posted back up with the results. Any feedback on why my floats stuck on me? Anything to prevent it?

thanks for all the help,
trey

scratch · October 07, 2004, 05:38:56 PM

How about a carb balance? Balance the vacuum between the two carburetors, so that you are getting the same air/fuel mixture being delivered into each combustion chamber.

Kerry · October 07, 2004, 11:30:06 PM

Quote from: treybradTook off the top hats so I could mess w/ the floats and what not. It didn't *seem* to be sticking, but i'm pretty sure it must have been (Srinath wins the prize).

I'm glad that everything seems to be working. But I don't understand how you were able to "mess w/ the floats" by removing only the "top hats".

As far as I know, you can't even see them without removing the float bowl from the bottom of the carbs.

You've stumped me!

treybrad · October 08, 2004, 07:55:44 AM

Hmm.. good point. You say float, I mean slide. Oops. Well, that gives me something else to look at, b/c it started doing it again. Maybe just me taking the tops off the carbs and everything jostled something, but after about 10 miles it started doing it again... So this time... i'll actually look at the FLOATS...

trey

Kerry · October 08, 2004, 09:52:28 AM

News:

One Plug Fouling?