The 'ol carb issue... looking for tech info if it's availabl


Information and questions on GL1500 Goldwings (1988-2000)
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waituntilthebeep
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The 'ol carb issue... looking for tech info if it's availabl

Postby waituntilthebeep » Tue Jul 23, 2013 6:13 pm



I got a wild hair and decided that since I had only owned the bike for a week and a half now, that I needed to do some preventative maintenance investigation on my bike. I got no idea what or when anything was done to this '89 GL1500 Wing so I grabbed a tool set and "got real intimate" with my ride. BTW... thanks to ALL the many who have posted how-to's on the 1500's as I have read a ton of forum posts all over the net and watched a crap load of video on these items as well. The good thing about all my digging was that I found out a lot about my bike. I found that I had a headlamp modulator already installed (saw the sensor piece installed and had no idea what it was for until I saw the video on installing one and confirmed the install when I took all the tupperware off). Also have one of those stop lamp flasher dealy's mounted under the seat. Got the side vent scavenger/heat ducts that are add on's too! Thought those were stock items. This is a good thing.

I went after the tupperware from the bags to the front wheel and stripped it all off. I got into the wiring and added a relay triggered by the running lamps that feeds a 3 outlet lighter style port thingamajig inside the trunk so I can charge my cell phone or mp3 player while on my commute. My bike has what I would describe as the low rpm lag that other 88-89 Wingers have complained about so I figured to look into everything that was listed as a fix. The carbs looked pretty clean all the way around but I hit them with a bit of carb cleaner anyway. The slides appear to move freely when I rap it up. I used ether around the vaccum lines to see if I could locate a leak and with the air cleaner assy on the bike, I can't get a rise out of any of the lines I could find. Even sprayed under the rubber mat under the carbs. My idle is pretty smooth.. I mean it does seek a tiny bit but it's within 50-100 rpm's.

What I am looking for is two things really:
1) This thing idles pretty smoothly. When I throttle it up without it being under load, the response seems to be really quick. I get a great shot of feul from each of the accelerator pump nozzles. However, the throttle response from 1300-1800 or so under load is pretty flat. I can either stay below 1300 rpm and hope to shift out of 2nd or 3rd and then roll into the throttle, OR I can give it hell and 1/3 to 1/2 throttle with a little prayer and keep the revs above 2500rpm until I get to 3rd gear or more. Otherwise the lag tries to destabilize the bike. In 4th or 5th, you can feel the lag right about where you need the throttle response to be. What are the symptoms of unbalanced carbs? While I had the left side tupperware off, I connected a vac guage to the left intake test port and I only have an average of 15-18" vacuum at 1000 rpm. No ideas what the right side is currently. I know that if a carb is too lean or rich, it will suffer performance wise. It smells pretty rich actually. I watched the video on balancing carbs and they had 22"+ or so. Would unbalance cause this hollow spot in the throttle curve?

Secondly, I started messing with the vacuum lines and found there to be couple that are in my estimation completely worthless. Looking at the pic below, a good many of them have no purpose but to make California air authorities happy. I deleted one because I could not get it back into where it belonged without removing the carbs. It is the orange striped one that is attached to what I assume is the ECM unit. It goes to 2 vents on the upper part of the carb and the "T" piece has no back so even of there was a vacuum, it would take a tornado hurricane to get it to pull enough air to even give the ECM a clue that it was sucking. This deletion looks only like an emissions protocol and the bike still runs fine with its previous hesitation. (EDIT - I looked closer at the California emissions vac diagram and my bike is NOT Cali emissions bike. I do not have the evap canister or the vac solenoids for that part of the system. Mine is a 49state'r)

Any ideas? Also had the 90 degree hose to the rear that is marked 18 replaced but according to the diagram, that line is also worthless as it doesn't ever get a vacuum applied to it that I can see. I put a guage on that port and verified my thinking and there is never any vacuum on either of the ports marked with "18" hoses.

Feedback is definitly apprecated....

GrantImage

2)



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waituntilthebeep
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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Tue Jul 23, 2013 6:57 pm

OK... I'm beginning to think that the low RPM issue has a mind of it's own 'cause even when I thought I had read all the posts I could and was seeing lots of the same answers repeatedly, I am still finding more lurking. So... Let me add one more element to the mix. With the engine at operating temp and idling smoothly (50-100 rpm variable fluctuation is my idea of smooth:-) I can slowly add choke and it is fine until it gets to about 1/3 choke application and then the motor sputters and misbehaves. As I roll the choke to 1/2 the motor then runs smooth again but with 2000 or better rpm but if I give it much more choke, it get raspy and gags... like overfuel, the gagging I would expect because it is way out of balance air to fuel now. The deadish spot in between 1/3 and 1/2 choke is somewhat baffling to me. I have experience wrenching on gas rigs ( many years ago) but my occupation is big rig diesels so I have been out of the gaspot game a long time.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby ct1500 » Tue Jul 23, 2013 7:36 pm

First off get your idle down to 800 where it is supposed to be, if it will not run there you likely have carb/vacuum leak issues. An orange stripe hose tells the ECM what operating conditions the bike is in, without that hose connected under carbs you got a vacuum leak and no ECM management for engine management and ign timing. The fast idle would mask carb/vacuum issues and show as a lower vacuum gage reading.

The early GW had a stumble off idle not in the 1300-1800 range, which was fine. A well tuned 1500 should idle all the way down to 550 RPM smoothly before stalling (mine 450 RPM) and is a good indicator of other issues if it cannot do this.

I think a carb inbalance is the least of your worries at the moment.
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waituntilthebeep
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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Tue Jul 23, 2013 9:16 pm

OK. It actually does idle at 800 without issue... had to go out and verify where it was actually set ;) That does somewhat answer a question I had but had not asked... was the stumble reported right off idle or anywhere else in the spectrum as nobody really put a number to it.
I will put a pic in that explains better what I am asking with my #2 question:

This is a "vacuum T" that is in line in the part of the plumbing that goes to the ECM. I find it impossible to believe that this "t" actually does anything since it's wide open to the air and the orifice hole to the ECM is super tiny. This is by design unless someone has changed it. If so, what was their reasoning? No idea. Should this be what is there now or did someone get creative? ALSO... if this combination of connections is supposed to actually provide a vacuum reference to the ECM, then why is there absolutely no vacuum at either of these two ports during operation?

This is the diagram I have been using to reference for my bike. The highlighted and orange lines are the ones in question.


I know I am asking alot of "why was this engineered this way?" kinds of questions. I am a watch the gears turn to understand the clock kind of guy. If I understand it's operation, I don't get stumped on it's troubleshooting.
Thank you for your input.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby ct1500 » Tue Jul 23, 2013 9:48 pm

Those are the bowl vent hoses and are not for the ECM which is the square component to the right of gas filter and just below. Don't worry about the vent hoses now, only when they piss out gas you got float issues. :D

First thing I would do is check for spark and ignition and do the RPM drop test. This will tell us if one side or the other might have carb problems or vacuum leaks at a particular intake runner which we can check later with some more pinpoint testing. A visual inspection of plugs is also advised.

Cylinders 1,3,5 right side front to back and 2,4,6 left side front to back. 3 coils, one for front, middle and rear cylinders each.

The 1500 should idle very smooth and runs like a sewing machine. :) What RPM are you able to get down to. It is a good indirect way of checking carb sync at the same time if one throttle plate closes way before the other limiting how low we can go. The choke is actually not a choke but cold enrichment rod which adds air and fuel, I wouldn't be too concerned with that right now.

A good visual inspection can usually spot a lot of problems, does it look like somebody has been into the bike before. When idling you should not hear any slight popping out exhaust, which is an indicator of vacuum leaks, should be smooth and quiet with no putt-putting.

viewtopic.php?f=14&t=17014
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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Tue Jul 23, 2013 11:06 pm

I was pretty far into it yesterday... almost to removing the carbs which I would have done had I had the right needle nose pliers to get the coolant lines off and back on. I do believe someone has been into it recently (within a year or two, as it was relatively easy to remove vac lines. I know when they have been on for awhile, they tend to bake on. These came off with a light twist and pull with a finger. I thought those two lines were bowl vents and that is why I was confused as to why that "t:" was connected to the ECM. Guesing it shouldn't be. If I read the schematic right, it should be connected to a "y" that comes from the manifolds below the isolators, not from the top of the carbs.

I will play with the throttle tomorrow while I am waiting for the ferry ride to work... I have to take a boat to get to work:-) The beast is terribly cold blooded but I hear that is common for these bikes. ONCE it is at full operating temp, I can unchoke it and it pretty much purrs. Currently dialed to 800 rpm. There is no popping or any other kind of noise while it idles. It does range about 100 rpm on its own. My Accord did the same thing:-)

I will follow your post as I get time. Working 4 -10's with a 4 hour round trip commute so the next 4 days won't be bike repair days. Truth be told, I'd rather be working on the bike than on the trucks :lol:

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby ct1500 » Tue Jul 23, 2013 11:17 pm

Cold blooded is what the folks who cannot figure out the problem call their bikes. In any kind of weather a couple twists of the throttle to add fuel and mine will start in a half second, and can be driven away.

Cold blooded usually means LEAN and when these vehicles hit the road 25 yrs. ago we had real gas.

Not the garbage ethanol of today which wrecks havoc on carb equipped vehicles.
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waituntilthebeep
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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Tue Jul 23, 2013 11:27 pm

ct1500 wrote:Cold blooded is what the folks who cannot figure out the problem call their bikes. In any kind of weather a couple twists of the throttle to add fuel and mine will start in a half second, and can be driven away.


This is why I ask for help :D I know it isn't right and it needs to be that way. Thanks for guiding me.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby ct1500 » Tue Jul 23, 2013 11:33 pm

One mechanic to another. :D
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Re: The 'ol carb issue... looking for tech info if it's avai

Postby virgilmobile » Thu Jul 25, 2013 7:05 am

I'll put in a word.The ignition control module does have a vacuum line with a "T" in it.The dead line is a test pore and normally is plugged.
All the vacuum lines must be hooked to the carb,there's 3 sets of them and go to control valves operated by the carb control module.It operates the valves at 3 different rpm ranges to better asperate the carb when needed.
I also had a lean carb around 2k.
I added a rubber "O" ring under the slide to lift it about 3mm off its normal rest position.
I can dig up the post if you need it.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Thu Jul 25, 2013 7:26 am

virgilmobile wrote:I added a rubber "O" ring under the slide to lift it about 3mm off its normal rest position.
I can dig up the post if you need it.


That would be helpful. I don't believe that I have crossed paths with any driveability posts regarding putting O-rings under the slides.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby virgilmobile » Thu Jul 25, 2013 8:32 am

I experimented with my OEM carb setup to eliminate it's multiple problems.
Each symptom had it's own target specific cure.
You must find out exactly where your trouble occurs ,eg: rpm,throttle position,choke usage to get the desired results then "adjust" that area of the carb.
The CCM module opens valves at 3 rpm settings to aspirate the ports in the carbs,I think one opens at 1500 rpm and the other opens at 2500 then both open at 3500.They really need to work..It makes a slight difference.
At one time,mine would stumble between 1500 and 2500,Add just a bit of "choke" and it would smooth out.This was the determining reasoning for lifting the slides.It needed just a bit more fuel for the low side of the mid range.
You need to comprehend exactly how the carbs supply the right ammount of fuel to air mixture for a specific demand on the throttle....Vacuum,air flow,meetering,fuel static level...they all come into play.Even a slight deviation from specs has a effect....

The bike idled and had the right mixture up to the rpm of the main jet,and in the higher rpm.Just the mid range suffered.
Here's the post for lifting the slides and the experiment that determined what I needed to do.viewtopic.php?f=6&t=12557

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Thu Jul 25, 2013 10:08 am

Cool. I will dig into it. I have been tied up at work so have not had any time to screw with this much but I did crank down the idle while I was waiting for the boat yesterday and I can rank it down to 500 rpm. it gets somewhat erratic below 800 rpm though. I am thinking about taking a couple days of vacation and pulling this thing down and verifying that the vac lines are all where they belong and that they are clear, etc. Will do plugs and timing belts too since I have no idea when these were done last...103k on it now.

You mentioned adding a bi of choke to get rid of the mid range lag and I tried that and I think it did work but it is all so temperature specific. What works now may not work in 10 minutes when the engine temp changes:-) Gotta get way more scientific with it. Thanks for the additional link. Will look into it tonight

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby virgilmobile » Thu Jul 25, 2013 11:03 am

It was kinda hard to simulate.I drove the bike in 2nd and held just at 2k.Gently moved the "choke",at less than 1/2 way when the rpm's picked up and it quit sputtering.It was a very breif time for this to occure.It didn't stay at 2 k very long,the rpm picked up and I had to back off the choke for the 3500 rpm range.
It was hard to "adjust" the fuel mixture while accelerating by using the choke lever.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Sun Jul 28, 2013 8:09 pm

ok... I got "more scientific" with it:-) $50 worth of Seafoam later, most of the driveability issues have become non-issues. There is only 2 things I want to resolve with it and that is first of all, that it has to be choked to start even when it is 80 degrees outside. That drives me nuts. Secondly, is the mid throttle lag. If I give it about 1/4 choke when it is at full operating temp, it will not lag so that tells me I have a vacuum leak of some sort still that I gotta find. Still planning on doing a full tune up and going through every vac line on the bike. Gotta figure out why they had the vents and the vac line to the control module connected together still. Got high hopes though. It is becoming a really fun bike.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby bjatwood » Mon Jul 29, 2013 4:35 pm

My 98 after sitting in 80+ degree weather after working 8 hours "likes" a bit of choke when started.... It will start but not idle worth a crap at first without some choke.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby waituntilthebeep » Tue Sep 10, 2013 11:41 am

I have put 6k miles on it now without taking any time to address the bikes issues (summer house projects took priority) and now it runs worse than ever:0) Guess it's time to pull the carbs and tank them and really go after the vac lines. I know for a fact that the ECM is not connected to the vacuum system and I would hazard to guess that this is a big part of the reason why it runs the way it does. Bummer.

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Re: The 'ol carb issue... looking for tech info if it's avai

Postby amsoilguy » Tue Sep 10, 2013 1:20 pm

Keep us posted on how things go...I'm in the process of doing the same thing.


Allan

'88 GL1500


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