Carb crisis


Information and questions on GL1100 Goldwings (1980-1983)
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gbh679
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Carb crisis

Post by gbh679 »



Hi Folks

This is a great forum and apologies for another Carb question but I couldn't see an answer on other posts.I'd be grateful if any Wing Guru's out there can help. I bought a non running GL1100 with a sump full of petrol. Carbs were all gummed up and petrol just ran out of them on the bench when I hooked up a fuel line so I thought that was the culprit. I stripped and ultrasonically cleaned them but had to junk carb 3 as the pilot screw was snapped and stuck in the carb body. I bought a second hand set of carb bodies off the net and fitted the bits out of my old carbs (float bowl, float, piston, spring etc) as well as all new o rings, needles and jets from a carb rebuild kit. I also fitted new air cut off valves. Anyway, having put it all back together along with fresh oil & filter, new plugs, new plug caps, it's all over the place. I seem to have fuel in the float bowls, a good spark, compression about 160 psi on each cylinder, I've checked valve timing and clearances but it'll only fire on choke after many minutes of turning over, just won't rev cleanly or tick over and has an occasional back fire when I rev it. Obviously it soon gets too hot for choke and dies completely.The plugs are OK apart from No 3 cylinder which is black and I'm not convinced it's running on all 4 at the same time. I seem to have fuel starvation as well as running rich. Could it be a vacuum issue or maybe the advance / retard? I was wondering about rings but the compression seems OK. This is my first GL and the carbs seem a nightmare. Could there be a fundamental mismatch between my carb components and the second hand carb bodies? Any thoughts greatly appreciated.

Cheers

gbh679


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Johnyy Smoke
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Re: Carb crisis

Post by Johnyy Smoke »

One of the first rules of carb rebuilding is to keep all the parts from each carb together, so as not to mismatch them. They do wear in a certain pattern, so it helps to reassemble them as original. This could be part of the problem. Did you do a bench sync?
Did you make SURE the floats are set to the correct measurement? They have to be exact "close enough" just will not work.
Double check timing, use the DIY article here to set the valves. Check fuel filter also. Regards, Johnny
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Overdog
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Re: Carb crisis

Post by Overdog »

Your 1980 carbs have pressed-in low speed jets. I'm not sure what year the change was made but my 1983 has screw-in jets. If the jets are clogged you will have idle issues....are you sure yours are clean? Like Johnyy said, float level must be spot-on. I learned this the hard way. As you did I got a carb kit and changed some parts...I got new floats in the kit but decided to re-use the old ones. I ended up with a bike that would start and idle just fine but wouldn't rev past 3000 RPM. I confirmed it as a carb problem by holding the throttle wide open (bike stuck at 3000 or so) and feeding small squirts of starting fluid into the intake. It revved right up to redline and sounded healthy. Out came the carb rack and the floats got adjusted. A suggestion for you (or anyone, for that matter) is if you have the rack off the bike and apart, before you re-install it get a longer section of fuel line...set the rack on a 5 gallon bucket next to the bike and connect the fuel line to the carb rack (no need to go through the fuel pump, gravity, right from the petcock is fine.) Turn the petcock on and let the carbs fill up and sit for a few minutes....check for leaks. Disconnect them and take them to a bench & work the throttle by hand...you should see a needle-fine squirt of gas out of all four carbs. If not, your accelerator pump passages are plugged. You could also carefully drain each float bowl to re-check if the floats are set the same in all four. ....and, as was mentioned, bench sync them before you put them back on.
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Overdog
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Re: Carb crisis

Post by Overdog »

You say #3 plug is black....is it wet or dry and sooty? If your float needle isn't seating #3 could be running way rich & maybe the other float bowls are getting less gas than they should because of it.....just a thought
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gbh679
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Re: Carb crisis

Post by gbh679 »

Hi Folks

Thanks for the feedback, appreciate it, some good points there. Starting to wonder if I'm over fueling on 3 and no fuel everywhere else. Will strip the carbs down again and double check for blockages and float needle seating, heights etc. Will probably revert to my original bank of carbs (as i know it matches the slides, floats etc on 1,2 & 4) and just swap out for the number 3 carb that I had to replace.

Quick double check on the bench as well for fluid levels and fuel output from the carbs.

It definitely fires OK if i squirt fuel into the air box so I have fuel in the bowls, just not in most of the combustion chambers!

Once again thanks.

gbh679
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RBGERSON
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Re: Carb crisis

Post by RBGERSON »

YOU need to pull the idle jets..most use a sheet metal screw into the jet lightly then pull and wiggle until the jet pops out..some use an easy-out. Be careful you don't want to bugger up the opening. Setting the floats must be done with the carbs tilted up on end. Bench testing for leaks done with the caps and slides out..if leaking up through the jets = float setting or float seat issues, out of the carb to plenum joint = o ring issues at that point, up through the plenum seam = plenum gasket. On the bench the carbs must be leveled, I use a small level across the plenum to check level and the fuel source at least 5' above to get right PSI. see pic but mine not high enough..


HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB
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gbh679
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Re: Carb crisis

Post by gbh679 »

Hi Folks

Just a quick update. Managed to remove the pressed in idle jets and all of them are blocked with old fuel residue and corrosion. So much for the ultrasound bath. Photo below. The new shiny one came with the carb rebuild kit so I'm assuming this is for the 1983 onwards carbs. I had to work these quite hard to get them out so don't think I can re use. Hopefully I can find a kit with them in. One problem down, a million to go!!

Thanks for the help so far.

Gbh679


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gbh679
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Re: Carb crisis

Post by gbh679 »

Anybody know what this pipe thing is? Found it in a box of bits that arrived with the GL1100.

Thanks in advance.

Gbh
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Johnyy Smoke
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Re: Carb crisis

Post by Johnyy Smoke »

Looks like the hose that comes from the advance to the #3 carb, and up to the plastic box under the false tank. But it seems to short for that. Regards, Johnny
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gbh679
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Re: Carb crisis

Post by gbh679 »

Nice one thanks. There must be another bit somewhere.
indianakid
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Re: Carb crisis

Post by indianakid »

OK.....................

that is not a vacuum advance line. also the vacuum advance line only goes from #3 carb to the advance unit, it does not go to the air box.

since no reference to size was mentioned i am assuming that it is about 1/4 inch (6mm) which would be the correct size for a fuel line and it has what looks to me to be a filter. it is my opinion that the PO had an auxiliary fuel tank and that is how it was T'ed into the fuel line before the filter and pump. I had done this same thing years ago when running cross country on my 81 standard. I had a 3 gallon moon tank on the luggage rack to give added range. in your picture the end on the left would connect to the petcock and the vertical line would connect to a shutoff valve and additional line would run to the aux tank. from the right end (fuel filter) the line would hook to the pump. That is how I routed mine. With both tanks full I would have the bikes petcock off and run the aux tank till empty. then close that valve and turn on the petcock to main. by using the aux tank first i would always have a known fuel quantity in the bikes tank.
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Johnyy Smoke
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Re: Carb crisis

Post by Johnyy Smoke »

I disagree, if you look at a Gl1100 bike you will clearly see were the hoses connect to the #3 carb, and go up to the false tank from the T junction. I suppose that the aux fuel tank theory is valid, if your running the bike were gas is not available, however, it does make one wonder just were that would be. Nor would I be comfortable with 3 gallons of gas on my luggage rack. Sounds like a solution to a problem that doesn't exist
Regards, Johnny
indianakid
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Re: Carb crisis

Post by indianakid »

OK.......................

you have the right to disagree. and you can have your opinion as to what a picture looks like or how much auxiliary fuel to carry on your bike. however the fact is on a GL1100 there are only two lines from the air box. one on the left side coming from the crankcase vent and the other to the over board vent that ends in the catch can. the vacuum advance line is a single hose about 3/32" from the #3 to the advance unit.

by the way i was going from California to Homer Ak through Canada and extra fuel was a very good thing to have.
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Johnyy Smoke
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Re: Carb crisis

Post by Johnyy Smoke »

I believe we are discussing two different things.
In the photo below, the "T" junction is clearly seen.
The hose comes from the advance to the #3 carb, the hose at the "T" routes up under the false tank and is attached to a small plastic box mounted to the false tank. (not the air box)
I would assume the box is some sort or regulator? Regards, Johnny


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gbh679
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Re: Carb crisis

Post by gbh679 »

Folks

I'll get a dimension for the pipe tomorrow but I don't think it's big enough for a fuel pipe, certainly it's only a 3 or 4mm bore. Assuming this should be connected to the advance / retard unit and isn't, then that's maybe another one of the millions of reasons it doesn't run properly identified.

Cheers for your help.

Gbh
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gbh679
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Re: Carb crisis

Post by gbh679 »

Hello

Quick carb related questions.

1. Despite much soaking in cleaning fluid and a couple of passes through the ultrasonic cleaner, I can't see light through any of the four idle jets. The small holes in the side are clear but there is no passage through the jet. My question then is should there be?

2. 3 of the carbs have the part number 49A A SB^. 1 of them has 49A B TA ¥. Is this just a batch number or is one a different type?

Many thanks

Cheers and all that

Gbh
indianakid
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Re: Carb crisis

Post by indianakid »

the idle jets stock are #35. which for Keihin means the fuel orifice is .35mm (.0137 inch). a guitar string is my most ready supply of wire in that gauge. the high E with a medium set from the acoustic is .013.
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gbh679
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Re: Carb crisis

Post by gbh679 »

Thanks for that tip, I'll continue soaking them and ambush a passing guitarist.

Many thanks

Gbh
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Overdog
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Re: Carb crisis

Post by Overdog »

gbh679 wrote:Hello

Quick carb related questions.

1. Despite much soaking in cleaning fluid and a couple of passes through the ultrasonic cleaner, I can't see light through any of the four idle jets. The small holes in the side are clear but there is no passage through the jet. My question then is should there be?

2. 3 of the carbs have the part number 49A A SB^. 1 of them has 49A B TA ¥. Is this just a batch number or is one a different type?

Many thanks

Cheers and all that

Gbh
#3 carb is different...it has the accelerator pump and the fuel inlet so I's suspect that it would have a different part number
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gbh679
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Re: Carb crisis

Post by gbh679 »

OK folks. Another question for you. Carbs have been stripped and cleaned (idle jets pulled and cleaned even), put back together, float bowls set to 15mm, pilot jets out by 3 turns, carbs bench sync'd etc etc. I put them on the bench (level), using a temporary fuel tank suspended 3 feet above the carbs, connect up the fuel hose, turn on the tap and wait. Takes about 10 - 15 seconds to fill up the float bowls and then it's raining fuel!! Petrol running out of the carb outlet on No1 and No 4 carbs (and also filling up the plenum). So, what do we think? Have I cocked up the float settings badly or is gravity overpowering it? As the bike had a sump full of fuel when I bought it this is obviously not the first time the carbs have dripped everywhere. The floats have been set to 15mm from gasket surface to the lower edge of the float right at the point it's starting to push in the float valve.

Thanks for all the responses so far, much appreciated.

Thanks in advance.

Gbh
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RBGERSON
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Re: Carb crisis

Post by RBGERSON »

It depends where the gas is coming from..up through a jet or at the carb to plenum joint..I am assuming it not coming from the plenum gasket as you specified leaks at specific carbs.

So with caps and slides out..is the gas coming up through the jets?? If so issue with float setting OR float needle valve or seat..not sealing.

If not up through the jet then it has to be at the carb to plenum o ring..did you change those out to new???

Also if the tabs on the floats are bent too much it could throw your float setting off..I like to straight mine out and get them flush/level with the surrounding brass bracket and then level the floats..did you do it with the cabs standing on end like this?? setting the bottom ones then flipping the carbs and doing the other two??


HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB
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gbh679
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Re: Carb crisis

Post by gbh679 »

Hi, thanks for the feedback, much appreciated. Had a session on the carbs tonight and noted this:

Set carbs up on bench as suggested without caps & slides. Turned on the fuel and nothing!! No sprinkler system like before, nothing coming up through the jets. Wondering if dry seals etc needed to bed in. Anyway, It's taking about 200ml to fill all four float bowls and they seem to shut off OK. Drained the float bowls into a cup and marked the level (no idea of the volume, it was just for indication) for comparison, they were all at a height of 22mm to 24mm so pretty consistent. Turned on fuel again and it took another 200ml to fill them back up. 50ml each, does that sound right? I set the float levels with them up on end like your photo.

Leaving the fuel on for a few minutes I noticed a leak where number 3 carb is attached to the plenum so your point above is correct and no, I didn't use new seals here (d'oh!) as they weren't in the kits.

Think that even with the slight leak I might still put them back on and see if it starts having cleaned and replaced everything. At least I'd know if that's made any difference.

Cheers

Gbh
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RBGERSON
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Re: Carb crisis

Post by RBGERSON »

The leak will be bigger when hooked to the pump..you could try blowing into the fule source tube and see what happens..applied pressure...or raise your fuel source above 6'..
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB
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gbh679
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Re: Carb crisis

Post by gbh679 »

Thanks, I'll probably order some new carb to plenum O rings and wait a few more days before trying to start it. On the off chance it might actually start then it would be pointless to have to take it apart to fix a fuel leak.
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gbh679
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Re: Carb crisis

Post by gbh679 »

Bored with waiting I put the carbs on and had a go at starting it. Still nothing, not even a cough. I know I have petrol in all 4 carbs and that it's taking 200 ml to fill all the carb bowls (and they all have a similar amount of fuel in them) but I'm getting nothing out of the carbs, the plugs are still dry.

Running out of steam a little. I need to see if the slides are moving so I'll use an inspection camera tomorrow but this is common across all 4 carbs. Does the fuel quant above seem correct? 50 ml per bowl?

Cheers

Gbh


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