GL1100 running lean?


Information and questions on GL1100 Goldwings (1980-1983)
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LilJohnWayne
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Location: Shreveport LA
Motorcycle: 1983 Gl1100 1978 Gl1000 1983 CB750

GL1100 running lean?

Post by LilJohnWayne » Sun Feb 15, 2015 2:32 pm



I used Randakks rebuild kit and replaced every wear item in the carb rack. I have a clean air filter that is OEM. I checked for air leaks including around the plenum-to-filter surface. I did adjusted the pilot screws to 1/8 out from highest idle, since highest idle is usually a hair lean. I've always had best results with this. I did a very precise carb sync. All of this worked out well on my GL1000 but for some reason I have different results here.

I take the 1100 out and it roars great through all the gears, sometimes spins the tire going into second gear. Pulls like a monster. Even in 5th, going from 70 to 80mph is effortless.

Temp gauge only goes over half until the thermostat opens then it stays at half or just below. Never gets hot.

This is all great. I'd call it a day and be happy except that the plugs are a concern.

They are white. No color even around the base. The top thread is a little gold brown and the tip is burned up to the 90° bend as I expect, but it just won't get any color on the center. There are maybe 3-4 tiny black specks on the insulator as well, which I'm told is molten aluminum from overheating.

There are no other symptoms. My GL1000 has a very very light tan around the base and no black specks. Should I be concerned about my 1100??



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Aussie81Interstate
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Motorcycle: 2001 GL1500F6C Valkyrie
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Re: GL1100 running lean?

Post by Aussie81Interstate » Sun Feb 15, 2015 4:01 pm

I would richen all carbs up a little - maybe a 1/4 turn - and check again.

you don't want to see molten aluminium on your plugs - as you know it is coming from the tops of your pistons...and at some future point in time you might get a rather large hole in one..

just my humble 2 cents worth.. I would err on the side of caution...

LilJohnWayne
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Motorcycle: 1983 Gl1100 1978 Gl1000 1983 CB750

Re: GL1100 running lean?

Post by LilJohnWayne » Sun Feb 15, 2015 4:54 pm

If I'm cruising at half throttle, how can the pilot adjustment have that much of an effect?

Just a question, but is there any possibility that a faulty, weak, or bypassed ballast resistor could cause this? I don't suspect mine but should I?

Here's what all four plugs look like. Heat range 8.



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Aussie81Interstate
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Re: GL1100 running lean?

Post by Aussie81Interstate » Sun Feb 15, 2015 5:03 pm

Is the fuel flow adequate - and float height correct - no vacuum leaks.. then I would go a main jet one size larger. You running at any altitude? what type of fuel are you running - any octane booster being used?

The plugs can change colour and if you pulled this out after idling for a short time - this could be the result - did you do a plug chop and then take out this plug - or just slow down and stop the bike then remove it.

A normal plug chop would be to ride at the required speed for a few minutes - then hit the kill button and clutch in and coast to a stop - then remove the plug - have a picture then. What type of plug are you running?

f1xrupr
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Motorcycle: 1980 gl 1100 Std. Vetter

Re: GL1100 running lean?

Post by f1xrupr » Sun Feb 15, 2015 10:23 pm

You may already know this-the float level in a gl carb determines the mix-higher float level is rich-to low is lean during above idle operation. That plug in your picture looks kinda "hot" (long tip)-is that what the specs call for on that year? I have a 1980, and my plugs have a strange color-my electrode looks ok, but, my ground tang is white-white...I don't know why-it runs great...I use 1 step cooler plug than calls for, in effects to help prevent "low rpm growl"...I found a colder plug and 93 octane helps with that (fresh top end), and that might be my color difference....IDK
My exercise bike is a goldwing.

LilJohnWayne
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Motorcycle: 1983 Gl1100 1978 Gl1000 1983 CB750

Re: GL1100 running lean?

Post by LilJohnWayne » Tue Feb 17, 2015 1:40 am

I have an 82 and the tag on the frame calls for DPR8EA. That's what it came with and that's what I use. I'm going to try a heat range cooler.

I know that the height is correct to about 0.01mm if not less. I've done many floats and know how it's done properly. The pump is flowing very well, fuel filter is new, and there's never any lurch that happens when a bike runs low on gas. For instance I set my float levels low (high) on my VT1100 and when you would sustain a speed the bike would suddenly bump you forward in the seat as it lost power and turning the throttle to compensate only made it fart and never could go faster.

This bike can pull to redline and makes power everywhere above 3k. In 5th, accelerating is kinda weak until you get over 3k but it's overdrive so it's perfectly normal to need more revs. My VT1100 is the same in 4 and 5th gears because they're actually both over drive.

I would understand if one cylinder was lean, but all of them to be equally lean? I'd expect that if I changed to a performance air filter or exhaust but it's totally stock! I'm lost.

Timing is spot on and the vacuum increases advance.

f1xrupr
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Re: GL1100 running lean?

Post by f1xrupr » Tue Feb 17, 2015 8:05 am

Yeah...that 3k mark is relative to my bike also. One would think that if you had a lean problem of concern, you would experience exhaust popping (maybe on decell). Hey, maybe that's my deal...I have retrofit exhaust...do you? I don't have popping on decell-it's more like gurgling...sounds kinda neat....hey-I made a new exhaust sound term-"gurgling"...!
My exercise bike is a goldwing.

rkmason
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Motorcycle: 1981 GL1100 Interstate

Re: GL1100 running lean?

Post by rkmason » Thu Feb 19, 2015 11:30 am

I read your post and just took a look at the plugs in my '81 GL1100 (100% stock w/ newly rebuilt carbs). My plugs look very much like yours. I rode the bike about 200mi in one day last week and got right at 40mi/gal which I think is normal for these bikes, but I do agree with you that the plugs seem to indicate a too lean mixture. At highway cruise speed I thought I felt a little lean surge from the engine but it was minor enough that I'm not 100% certain. Could've been wind buffeting.

Do you intend to do something to richen the mixture?

UrbanPeasant
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Location: Manchester, UK
Motorcycle: 1981 GL1100

Re: GL1100 running lean?

Post by UrbanPeasant » Sat Feb 23, 2019 7:26 am

I've bought and heavily modified a pilot screw adjuster, but I can't hear the difference being made as I turn the pilot screws.
Would you mind telling me whether winding the pilot out richens the mix, or leans it off?
I'm pretty happy at present with my carb rebuild, and mercury shows me that I've got a fairly decent sync, but presently I can't tell if I've got the pilot screws optimally adjusted (I'd like to err on the rich side). Haynes just says start at 1 1/4 out, with no indication of what out or in actually does.
Thanks
Nathan.

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dingdong
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Re: GL1100 running lean?

Post by dingdong » Sat Feb 23, 2019 9:28 am

Have you checked the output of the fuel pump? I just went through the same problem with my 76. Since all four plugs show the same color that is where I would go next. There just wasn't enough fuel to feed all four carbs under heavy accel. I ended up installing an electric pump and plugs are back to normal.
Tom

John F. Kennedy would be impeached by todays liberal Democratic socialist party.

UrbanPeasant
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Motorcycle: 1981 GL1100

Re: GL1100 running lean?

Post by UrbanPeasant » Sat Feb 23, 2019 9:42 am

Hi dingdong (!)
I've checked the fuel pump, had it in bits, made sure the diaphragm wasn't holed, rebuilt, aimed the output pipe into a container and pushed the starter to draw fuel (did this after doing a resin liner in the fuel tank, and prior to pushing fuel from the pump into my clean carbs). I get good solid squirts out of it, though I've no idea what the pressure is.
A lot of work has gone on with this bike lately as it's been stood for a long while (several years since my parked it and left it, hence the carb rebuild and tank liner for starters). But I still don't know what winding the pilot screw out does to the fuel mix. I just tried pulling away in 1st gear on the drive , but all it does is stall. Feels like another part of the fueling puzzle to me.

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dingdong
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Re: GL1100 running lean?

Post by dingdong » Sat Feb 23, 2019 10:12 am

The pilot screws adjust the "fuel" at idle. Out equals more fuel to idle circuits.
Sounds like you may have eliminated the fuel pump as a problem. BUT I did the same tests with mine and there were no tears or holes in the diaphragm and the flow seemed okay. Nothing else fit the symptoms for all four carbs so I replaced the pump with success.
Tom

John F. Kennedy would be impeached by todays liberal Democratic socialist party.

UrbanPeasant
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Re: GL1100 running lean?

Post by UrbanPeasant » Sat Feb 23, 2019 10:47 am

Excellent, out = rich. I understand it's only for idle running. I guess that's a good place to start really, rich, and having looked at my plugs, that'll likely explain the blackness. So I'll go and deal with that.
The pump, I do have a second '81 1100, that I just acquired last weekend. This one has had a much better life and has been stored in a dry, dehumidifed garage all its life (a close, long-time friend of my Dad's bought it new, and after 38 years of ownership 'donated' it to me). I'm sure that pump, though old too, is good. So I'll give it a try before I get too despondent today!
Thanks for sharing what worked for you, and for putting me straight about the pilot screw in/out question.
Nathan

UrbanPeasant
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Re: GL1100 running lean?

Post by UrbanPeasant » Sat Feb 23, 2019 11:51 am

It's not the fuel pump. Bugger it. Same problem with the pump from the other bike.
I'm going to have to swap the carbs out, and see how I get on then. Maybe something's still blocked.
Don't really want to have to do that because the other one is all correct together, and on the road.
There's only so long I can go on beating my head against a wall.

UrbanPeasant
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Re: GL1100 running lean?

Post by UrbanPeasant » Fri Mar 15, 2019 4:27 pm

It looks like the main culprit of my terrible running problem was the air cutoff diaphragms. Upon investigation (I'd been told the carbs were rebuilt 18-24 months ago) 3 of the diaphragms were knackered. One of those had been 'repaired' with silicone sealant! The rubber surface of all of them had deteriorated into a sticky mess, and you could see the fabric weave behind the rubber. The 4th diaphragm was new. What's that all about. It strikes me that these things are a bit like shocks or other wear items like that - if you replace one, do them both, or all, or whatever. Clearly someone cut corners.
This bike now starts on the first spark (by the sound of it), comes off choke quite swiftly, and settles into a lovely idle. There's a bit of hesitation when opening the throttle, but it revs and drops off cleanly with none of the puffing and wheezing that used to be going on through the exhaust. Each time that odd puffing happened, the vacuum on whichever carb was affected would drop to zero. That's gone now, carbs nicely synch'd. But I think it's rich now, and I can't hear a change in the revs as I wind the pilot screws back in.

I think I'll leave it as is and just ride it when the weather improves again and see how I get on.

Anyone reading this, don't scrimp on air cutoff valves if you've got running problems and have a wheezy, chuffing, puffing 'wrong' noise coming through the exhaust every few seconds.

Cheers for now.

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Overdog
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Re: GL1100 running lean?

Post by Overdog » Sat Mar 16, 2019 7:15 am

dingdong wrote:
Sat Feb 23, 2019 10:12 am
The pilot screws adjust the "fuel" at idle. Out equals more fuel to idle circuits.
Sounds like you may have eliminated the fuel pump as a problem. BUT I did the same tests with mine and there were no tears or holes in the diaphragm and the flow seemed okay. Nothing else fit the symptoms for all four carbs so I replaced the pump with success.

I thought the pilot screws on our Wings was an "air" screw, not a "fuel" screw. I thought that if the screw is on the engine side of the butterfly it would be a fuel screw...ours are on the outside of the butterfly. You can see the tip of the screw if you pull off an intake tube. Winding the screw out should let in more air, thus, leaner.....

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Maz
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Re: GL1100 running lean?

Post by Maz » Sun Mar 17, 2019 3:08 am

Definitely 'fuel screw'on 1000's - out increases fuel at idle i.e. richer.
Maz
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DaveO430
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Re: GL1100 running lean?

Post by DaveO430 » Sun Mar 17, 2019 6:00 am

Overdog wrote:
Sat Mar 16, 2019 7:15 am


I thought the pilot screws on our Wings was an "air" screw, not a "fuel" screw. I thought that if the screw is on the engine side of the butterfly it would be a fuel screw...ours are on the outside of the butterfly. You can see the tip of the screw if you pull off an intake tube. Winding the screw out should let in more air, thus, leaner.....
The mixture screw is on the engine side, the air/fuel goes toward the engine, not away from it. Irrelevant anyway, it is a fuel screw.

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Overdog
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Re: GL1100 running lean?

Post by Overdog » Sun Mar 17, 2019 10:35 am

LOL....don't know what I was thinking....I pretty much even said that the screw is on the engine side. :lol:

UrbanPeasant
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Re: GL1100 running lean?

Post by UrbanPeasant » Wed Mar 20, 2019 7:46 am

Landed on a video that explains the pilot screw quite nicely. Gets to it at about 8 mins having shown animations of the various circuits in operation on CV carbs like these. I'm almost certain the Haynes manual called this screw a pilot air screw. I'll check later, but I'm pretty happy now, it's fuel, and winding it out is letting more fuel up from the bowl making it richer.





I've just got rid of the 40 year old rubber hoses too, and got Hel hoses on now. Suffered the common complaint about bleeding the front, but got a decent-ish lever last night. Left the lever pulled in over night, and hope to get the last vestiges of air out of the system this evening. Then it's MOT time and I should have it on the road taxed, tested, and insured by the weekend.
All the best.
Nathan



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