Bowl levels are the same, sooooo.....

[Scud]

ok....just took a fifty miler and looked at the plugs, #1 still looks as though I just took it out of the box.

I swapped lcoil leads on #4 with #1 and vice versa...hmmmm.......#4 looks good.

Must be an air leak huh....

Looking on the outside of the #1 carb I did notice a little oily substance, kinda dark......

Sorry....just had dinner, went out afterwards and clamped down the boot between the carb and intake manifold then ran her for ten minutes in neutral, figured that would make some carbon and lo and behold......it did not....the plug still looks as though it came out of the box.


Well..what do you guys think?? :-k

Scud

 

[KEITH KRAUSE]

Well, your description of what happened with the 1/4 plug lead swap would suggest the spark is good.
That would leave carburetion and compression in that cylinder as possible problems.
I don't know. I don't know how a plug can fire, even weakly or not all the time, and leave no carbon on at least the outer rim of the plug. We all know a cylinder can run so lean that the insulator can stay white and clean looking, but no carbon anywhere? Defies logic. A cylinder not firing WOULD pass raw fuel through and the plug would stay new looking, but you would have to smell and see fuel out the exhaust too. You would also get some good, irregular backfiring because some of the excess fuel would "stick" to the header walls and eventually fire, causing the backfire.
And of course, the bike would run bad.

 

[Scud]

Thanks Keith, I guess I will have closer look at the boots and maybe tear into the carb again (hate doin that..) then let you all know what I find out.

By the way...what would a compression test tell me about this condition in the #1 cylinder?

Scud

 

[KEITH KRAUSE]

If a compression test shows low compression at #1, then combustion will be poor in that cylinder. Poor combustion means the mixture won't be exploding correctly and you lose power in that cylinder.
I still think that with some firing (you say the pipe warms up) that there would be at least a little carbon, but I suppose it's possible that all the raw, unburned fuel passing through could "scour" the plug and keep it looking clean/new? Very poor compression could cause this.

 

[Scud]

Keith, there was what looked like a very slight discoloration and I mean very slight around the rim with a few light brown spots. When I removed the plug there was a slight fuel smell.

Scud

 

[Anonymous]

Your problem comes from one of three issues. Some have already been explored some.

First - No spark. Swap 1&4 and see if problem moves to #4 (already done) but also remove #1 plug and then put it in cap and hold electrode about 1/16" away from cylinder. Turn engine over and observe spark jump. If you see one, move to step #2.

Second. No Fuel. I think you have BS34 Mikunis on your bike? I think these have a screw on the bowl that opens the drain. Back screw out and see if there is gas in the bowl. I think you have already done this so if there is gas, go to step #3.

Third. NO COMPRESSION - This can be caused by either bent or very burned valves, a holed piston or a broken ring. Whichever is the case will require disassembly of the top end for further assessment of the problem. Buy a press fit compression gauge from an autoparts store. They are about $30. Warm engine. Remove Plugs. Hold gauge so that rubber tip seats in plug hole and turn engine over with throttle held WIDE OPEN. If you don't hold throttle open, compression readings will be lower than they should. You may need to crank engine several times. Once you have the max reading, do other cylinders, in turn. A cylinder with the bad things I covered will have close to zero compression, depending on which one and how bad. With no compression, there will be no combustion.

Oh yeah, as far as rich and lean. Rich air/fuel mixtures will leave carbon deposits in your combustion chamber. They will form on the piston crown as well as the valves. Eventually the valves will have seat problems and any pinging will cause the valves to pit where carbon deposits have formed. Too rich is BAD. Lean causes more complete but much hotter combustion. Too hot and you will run into a gamut of problems.

Which discolor pipes? Well, most GS bikes use either factory or OEM 4 into 1 pipes that are single walled mild steel that is chromed. ANY air/fuel mixture and the pipes will eventually discolor in the header area. Lean will cause the discoloration faster because of the greater heat. Some bluing is normal and bluing comes after the pipes get a slight gold tinge. If bluing continues more than a foot down the pipes, this is an indication of lean.

 

[Scud]

George,

Thanks so much for the in depth diagnosis/problem solving text. I will look into a compression tester tomorrow ( I live in Droggs, Idaho...one auto parts store..may have to go to Rexburg and get one).

I will look for spark with the plug removed.

I did drain fuel bowl and it has gas, same amount as others actually.

None of my pipes are blue or gold, they are all still silver, no discoloration at all..hmm. I have the factory exhaust.

Thanks again,

Scud

 

[Scud]

I took a digital photo of the #1 plug and would like to post it for all to see but I do not know how to do it, anyone care to tell me so I can share this phenomenon?

Thanks in advance,

Scud

 

[steve4mc]

Yes but she runs good.

Yes but she runs good.

I keep coming back to your comment that she runs good. If you were getting no gas such that No 1 wasn't firing, it would drastically affect your performance. The same with no spark or weak spark. If it purrs at idle, does it still have all the power it should have? Personally, I would give my left you-know-what for a plug that looks new after 200 miles. Mine foul so bad, I end up putting new ones in after 500 miles. Maybe You should be content and ride like the wind.

 

[Scud]

Steve,

You know what? you are right, I should be content, but......I am a perfectionist unfortunately. I am worried about holing a piston but my exhaust pipes still look like new and she indeed purrs, in fact she fires right up after one-half a second after the starter button has been pushed, no choke when it is 90 degrees outside and with choke when it is colder outside. Sounds normal and like a dream does'nt it.

Then why does one plug look like new and the others tan or slightly on the dark side???? and should I be a worry wart about this.

I so wish to put this photo on this website...someone let me know the way and I will shed a lot of light on this subject for all to see.

Scud

 

[Anonymous]

Scud, to put an image on this site, I don't think you can do it directly. You have to have the image hosted on a picture hosting server. To do this, go to www.photobucket.com and open a FREE account. Once you have a username and password, upload a photo from your hard drive or a floppy disk to photobucket. It will then give you three options where you can copy and paste either a URL which is a link to the photo OR use the HTML tag they give you which is in the same form as the "Insert image" tag format above... for instance:

Here I cut n pasted the thing labeled URL:
http://img.photobucket.com/albums/v12/wiredgeorge/barney/barney1.jpg

Right below it is a another line marked Img. I just cut and pasted it and see what happens below:

[/img]

That purple bike is a disguised GS prototype bike bwhahahaa

 

[Scud]

Fantastic! I am playing a little baseball with my four year old tonight but tomorrow AM I will look into that.

THANKS!!!!

Scud

 

[Scud]

Ok, did this work??

If not let me know.

Scud

 

[Scud]

Hey, it worked!!! thanks George!

A little history:

This plug is a D8EA and has about 150 miles on it.

Scud

 

[Hoomgar]

Well it isn't like new but I have to admit that I am stumped 8O


What the heck? Lean usually gets all white, rich gets dark. But that is just
clean. I would think it has to be lean? Been following this thread and now
that I see the picture I think your bike may be even stranger than mine

I hope the pro's can do something with that pic because I have to agree
with you, it makes no sense at all.

 

[Scud]

It is strange, I just do not want to screw up my motor?!?

Scud

 

[gsBert]

scud: when you tear apart your carbs, can i ask you to give me the sizes of all your jets, your float heights and the carb model?
sounds like my bike could use 4 plugs like your #1...
your mixture might be RIGHT ON.
my racecar gave plugs like that.
so you might be in the clear, but it does look suspicious.
so you tried swapping plug wires. did you try THAT plug in cylinder #4?
if not try it. if it doesnt get dirty in cylinder #4 then maybe it's a bum plug.
something's definitely up with this. cylinder 1 should warm up at the same time as all the others.
you start your bike on the choke rihgt?
maybe carb#1 choke is clogged and the jetting is DEAD ON for your bike, the other plugs change color but since carb 1 isnt getting any choke it doesnt get any carbon.
i know its a whole truckload of maybees, but its weird.

if youre worried about holing a piston, get a temperature guauge of the kind you can stick on the cylinder head, and see if that cylinder runs any hotter or cooler than the others....

 

[Scud]

Bert,

While fishing this morning I thought that exact same thing that it may be DEAD ON.

This is a new plug, I replaced it because the other one looked the exact same after 200 miles, like new.

I will swap #1 and #4 plugs to see what happens.

I cleaned and put in new rubber in my carbs two years ago, I would rather not have to go through that hassle again. I can tell you that when I ordered carb kits the pilot circuit jets were larger and fouled the SH.. out of all my plugs until I replaced them with the original jets.

Float height is 22 mm on all.

Carb Model BS32SS

When the larger jets were in I did not have to choke the bike to start. Now I have to choke it only when cold wtih the originals back in.

I have not tried swapping plug wires but I did switch number four and number one coil wires with the same results.

The cyclinder warms up about the same as number four or very, very close and slower then the inside two.

Scud

The choke thing is something I will have to look at I guess.

 

[Scud]

ok...I swapped plug #1 with #4 and vice-versa then drove about fifteen miles.

The plug in question when placed in #4 did indeed darken to tan or a smidge darker.

The plug in #4 when placed in #1 lightened up considerably.

What does this tell you now???

Scud

 

[gsBert]

ok, 2 things are happening here.
first of all, your 2 outside cylinders get hotter slower than the inside ones you say. that's absolutely normal if all your jetsizes are the same and not to be worried about unless youre at wide open throttle. your 2 outside cyls have better airflow and cooling. that's why the stock jetting on these bikes is a tad richer on cyls 2 and 3 to get the cyls to run cooler because of the lack of outside air exposure. when you get your mixture right, richen the 2 inside ones by making the mains a bit larger. if you use 135s all around, use 137.5 on the 2 inboard cylinders.

second, you are using slingshot carbs, so you prolly have pods on them (they dont fit in the stock airbox) slingshots will only work if you have 2 filter pods, individual pods won't work on them. you have the proper k&n right?
now, check your idle screws, and make sure all of them are turned out the same number of turns from all the way in.
then, (i'm sorry but you'll have to open the carbs) make sure you have the same size pilots in all of them, and that the needles are in the same position) also check that all the diaphragms are hole-free.
while you have the carbs off, check that all your needles are the same and not worn (2-3-4 needles might be worn and give a rich condition) i apologise for this, but remove the main jets and tap the emulsion tubes out and make sure they are all the same and all the holes are unclogged.
(some tubes have 1 extra hole on one side, it doesnt go all the way through, check that one too)
22mm sounds too high a float height, what are you measuring from and to? especially since the flingflops are angled and dont sit at the right angle for our bikes... (thank god the float bowls seal properly)

i'd say your cylinder 1 is dead on but needs a bit of richening for safety, and the other 3 are slightly rich. good job on putting the original pilots back in. those flingflops are a real !@$$#!to tune so you have to experiment, i personally am on my 12th iteration on the 1150, and i believe i finally am getting close to getting my bike to actually start, lol.

ok, you dont have a choice, rent a bad movie and tear down your carbs while you're watching it, i think you'll find that there's a discrepancy somewhere, and you'll be really proud of yourself when you find out that say one of your slide holes was plugged with a piece of pigeon feather, or some other dumb thing like that...
dont be afraid of tearing the carbs apart, slingshots are real easy to do, by now i can build a complete set in 20 minutes with my eyes closed.

if the teardown doesnt reveal anything, there's one other thing you can try, but its gonna cost a bit if you don't already have a set of spare carbs handy (you don't? what a fool you are, i got 2 sets on my table and one on the biek right now) buy/beg/borrow/steal a set of carb bodies identical to yours and swap all the internals, see if the condition persists.

oh and yeah, one more thing, when you idle your bike, dont do it on the sidestand, keep it straight up.