3 lean plugs, 1 black plug....

[FlyingSteve]

Hey guys... So a couple days ago I was having trouble keeping my bike running. Sometimes when warming it up, it would just die for no reason and then would not restart for maybe 10 or 20min later. Well it did this on Friday and but it died after only warming up for 2min... I checked for spark and it was good and the fuel was flowing, so I went out and got new plugs and viola, she fired right up and has been running no problems... Except for what I found today....

So yesterday I had it out all day and I put about 40 miles on it through the back roads and city. I ripped on it a bunch of times and also casually drove it through heavier traffic. So today I changed the oil and filter and I pulled all the plugs to check the coloring... The 2 cylinders on the right hand side of the bike were white. As in the electrode was white with a light flaky layer on them and the center ceramic was virgin white. The outside cylinder on the left hand side (This is sitting on the bike mind you) was also white and the same as the other 2. The second spark plug in from the left side was BLACK. Like, completely black. I cleaned it up with a wire brush and some carb cleaner... But does anyone have some suggestions?

I'm getting ready to put the pod filters on in a couple of days but before I go and pull the stock airbox/filter setup off I want all the cylinders to be running the same and properly.

So a black plug, it's most likely running damn rich in that cylinder, but why? If all the jets/needles are the same... Then that must mean that maybe the float height isn't proper in that carb or the needle valve on the float is leaking? Or might it be something a little simpler?


** Could it also have anything to do with the valve adjustment? When I get my new valve cover gasket I'm going to pull the cover and check the clearances.
Thanks!

 

[rustybronco]

The second spark plug in from the left side was BLACK. Like, completely black. I cleaned it up with a wire brush and some carb cleaner... But does anyone have some suggestions?

Depending on what bike you have (put it in your sig line) it could be because of a bad petcock.

 

[TitanNeil]

Pull the vacuum line off the petcock and see if there is any gas or fuel residue in it. One possibility is that the diaphragm inside is torn and fuel is getting sucked down the vacuum line into cylinder #2. If it is bad enough it might even starve the other cylinders for fuel?

 

[Guest]

I had a similar problem and I found................

1 -- The main jet in one carb was ready to fall out .
2 -- The previous owner had fitted an incorrect o-ring in another carb main jet which didn't seal properly .

Fixed both and all good .

Cheers , Simon .

 

[hampshirehog]

As above or maybe a choke that's not closing off properly (weak spring, worn rubber etc).

 

[FlyingSteve]

It's an 80 gs550.

It's not the petcock because I've had the tank off many times and no fuel leaked from the petcock nor was there fuel in the vacuum line. And after I open the choke I always push the rod on the carbs to make sure it's all the way in... I guess I'll just have to pull the carbs and see if I can find anything. The bike runs pretty good despite the issue... The only other thing I can think of as to why the other plugs show lean is because I put the dual exhaust on from a Katana, which is a megaphone style and has more openings than the stock 550 exhaust, so it flows a little bit better. The bike runs good and is smooth through the whole power band, so maybe something funky is up with that carb like a loose jet or something then... Because if the other cylinders are lean because of the exhaust system, than that cylinder should also be lean, unless something is allowing more fuel in.

I'll give everything a good looking over and I'll double check the petcock. Lucky enough I ordered a new o-ring set from cycleorings guy a few weeks ago so I have those on hand if need be!

 

[Ohioan]

from one newbie to another;

read this: http://www.iwt.com.au/mikunicarb.htm it will help you understand what's going on inside those carbs.

there is a section on "Carburetor Jetting Troubleshooting" that will tell you how to see where the problem is. You'll drive yourself crazy taking wild stabs in the dark at the issues (trust me, I've been there).

 

[FlyingSteve]

Thanks, I'll have a look at that site and see if I can't learn something I don't already know. I should say that I'm not a carb noob though. I've worked with Kehines quad carbs before and top-draft carbs on cars as well. Just figured I'd ask my questions here first since I'm new to these bikes and to get some input is always good.

 

[Guest]

Sounds like it'll be something specific to that cylinder or carb rather than something common to all the pots .
Good luck and let us know what you find .

Cheers , Simon . :-k

 

[Guest]

If they are VM's turn the pilot fuel screw in a 1/4 turn and see if the black plug lightens up a bit. If it does, you might want to turn the other three out a bit until they are all are the same color, chocolate brown would be right. If the others do not darken up, your jetting may be too lean. If the pilot screws are still painted in so they don't turn, you are long overdo for a complete strip down, a good soak and clean and new 'O rings.

 

[FlyingSteve]

They are the BS32's or whatever the number is that came on the 80 550E. I have a feeling that the 3 cylinders are running lean due to the exhaust system. I'm gonna pull it apart tomorrow and I might even just try to get the pod filters on right away. If I'm gonna pull the carbs and screw with this stuff I might as well just "once and done" it. I really don't feel like having to take that stupid air box off over and over. And actually riding along, when I get up to around 5K RPM, if I give it more throttle the RPMs start to shoot up quick but my speed doesn't increase in relation.... Now you'd think that would be clutch related, but at lower RPMs it pulls just fine and it doesn't do this until you get up to around 5K... Making me think that it's really leaning out around there.

 

[Big T]

Your clutch is slipping when it hits the power band

I hope you have jets or a jet kit if you're going to put pods on it

Sounds like it was never jetted for the pipe, and you are on your way to frying your motor

 

[Guest]

Time for a rebuild. Those are CV's I guess, I've never worked with them. Do Your self a favor and keep the air box no matter how much a PITA it is, and leave the exhaust as stock as possible. A rebuild and hanging yourself out into unknown territory with complete re-jetting is a much bigger PITA. Ask me how I know.

 

[BassCliff]

Hi,

I would tend to agree with the experts' consensus around here regarding the fouling #2 plug. It doesn't take much gas leaking down the vacuum line to foul the plug. (See #13 in your "mega-welcome" list No. 2.) Also, it is "best practice" to first get the bike running well in its stock form, or in whatever configuration you acquired the bike (See "mega-welcome list No. 1) . Then you have a baseline to measure against when you start making modifications.

But, in general, it is possible to install good K&N pods and a 4-n-1 pipe with a Dynojet Stage 3 kit, follow the instructions, and you'll be close as long as all the other pieces of the puzzle are in place (clean carbs, adjusted valves, good electrical/charging system, etc). Keep us informed.

Thank you for your indulgence,

BassCliff

 

[FlyingSteve]

Your clutch is slipping when it hits the power band

I hope you have jets or a jet kit if you're going to put pods on it

Sounds like it was never jetted for the pipe, and you are on your way to frying your motor

Meh, I had a bad feeling it was the clutch slipping. Now I wonder if it's just the springs that need to be replaced or if the friction disks are shot. Just another thing to **** my money away on this damn bike. By the time I'm done with it, everything will be new and I'll be broke.

The "pipe" as you so call it is nothing more than the stock exhaust system off of an '80's Katana... Same motor/frame setup as the gs. I just put it on and your right, it's gonna fry the motor, which is exactly why I'm not gonna ride it anymore till I get the jetting resolved. I don't have a jet kit and I'm not going to **** the money away on a DJ kit. I'll get the jets at the dealership.

I appreciate everyone's advice. However if your advice is to keep the stock intake system because you failed at pod filters, then please take a hike from my thread. If you have no knowledge to contribute other than n00b rantings, then don't waste the server space or bandwidth. I don't mean to come across like a jerk but I'm really sick of hearing it. Specially when there are a lot of pod filter users that have no issues. And no, not every person that successfully upgrades their fuel system does it with a fricken DJ kit.

K, thanks.

 

[Big T]

Steve.

The general consensus among those who have rejetted BS carbs is that the adjustable needle is a must have, and that appears to only be availble in a kit

You're correct in that many have successfully run pods and pipe on their BS equipped bikes. Most have long tales of getting the jetting to work correctly.

Others have just gotten ****ed off and went back to the stock airbox

BTW, jets are much cheaper at www.jetsrus.com

Keep us posted on your progress

On your clutch, the fiber plates may be glazed. Pull them out, measure them and scuff them with sandpaper on a piece of glass and reinstall. Your springs may also have worn out after 30 years. I know ,such cheap stuff the Japanese make!

 

[FlyingSteve]

We'll just have to see how it goes then. I bought this bike with the intention of turning it into a cafe/naked bike, not keeping the silly stock crap.

I know about jetsrus, however it isn't really cheaper after you pay the 7.50 shipping and then have to wait how many ever days it takes to get your jets. I can get OE jets at dealership for 2.75 each and have them in my hands immediately.

As for the needles... Is it just that they are adjustable or is the needle taper actually different as well?

 

[bwringer]

As for the needles... Is it just that they are adjustable or is the needle taper actually different as well?

Yes, the taper is different.

And I still suspect that your petcock is bad. Just because it doesn't leak sitting on the bench doesn't mean anything. All it takes is a microscopic leak under vacuum to foul the #2 plug.

Might as well get the jetting in the ballpark before riding some more, but I bet if you disconnect and block off the vacuum port and then ride around for a bit with the petcock on "prime", you'll find that the #2 plug suddenly matches the others.

 

[sparki]

when you say it's black... sooty black or oiled up black?

 

[FlyingSteve]

Eff me running... I took the right most carb slide out and there was all ready a .5mm washer shimming the needle... The PO must have put it there. Since I don't feel like yankin the gas tank off just yet (Because the custom seat pan I made is a PITA to get off with the stock air filter box on), I'm just going to experiment with shimming the needle on that carb until I get a good plug color and then I know what I'll need for the other carbs and then I can work on the jetting.