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Okay, I can't figure it out.. 2000GL150SE, 17,000 miles.. the bike basically runsvery wellafter warmup... fast, smooth, etc. while underpower.. a slight "burble" at idle, but idles steady. 40+ mpg over last 4000 mies (better than most 1500s).. very slight hesitation at start off idle, but not enough to complain about.. new oil, air cleaner, sub filter, ...

Here is the problem that I am chasing:

At cold startup, with choke/enrichment "on", bike starts instantly, but only on 3 cyls (2/4/6) as confirmed by sound and exhaust header temperature. After 15 secs or so, by slightly openingof the throttleand simutaneously reducing the choke/enrichment, the engine will come to life on all 6.. It will then warmup and be "choke" free in about 2 minutes. The problem is the 3 cylinders at startup

Here is what I have checked:

(1) spark: not suspected, but checked anyway - okay

(2) carb sync suspected: checked and very precisely balanced at hot idle and stays balanced with increasing throttle; slightly mismatched at idle with enrichment "on" (about 1 in-Hg).

(3) Enrichment valve operation possible suspect: both sides appear to be working the same, at least from external mechical inspection.

(4) I've run Seafoam several times with no improvement.

So here are the Questions

(1) How does this enrichment circuit actually work? is it adding ONLY fuel, or is it adding extra air as well? My guess is that there is additional air (the revs should go up) but so far have not been able to confirm that.

(2) Are there externally accessible/cleanable air passages that can be cleared, or is it necessary to remove carbs? If there are air passages, where are these "holes"?

(3) It could be that there is a blocked fuel or air passage. How do I determine which?

(4) Would pilot screw adjustment cause (or correct) this? Seems to be fine after warmed up.

any other comments

Thanks in advance..

SDB/Jim
 

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The enrichment valve is actually a carburetor within the carburetor. The enrichment carb runs very rich but is very small. It enrichens the mixture enough for relatively cold starts. If it were me I would start the engine and let it run on 3 cylinders for a while. Stop the engine and read the plugs. Compare one's that fire to those that don't. That should tell you if it is rich / lean on suspect cylinders. Also note if they are wet with fuel. Smell for gas on plugs. If you had a marginal coil it might not create enough spark to fire a lean mixture as lean requires more voltage. Maybe when you burp the accelerator that richens it enough to get it to fire and it continues. The enricheners can be serviced without disassembling carbs. It is actually quite easy. Just watch for small parts if you have big hands like me. Small parts disappear in to the air when in my hands. Disasemble and blow out with reason. Also inspect the enrichener spring needle and seat.
 

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Thanks redwing52.. I assume from your comments (i.e. carb within a carb) that there are separate air passages in addition to fuel passages that are opened.. true? if that is the case, then I suppose it could be air passages and/or fuel passages that are a problem..

Good idea on the plugs.. I know it is the 1/3/5 side that is not firing (cold side), but looking at the plugs will be a good way to tell if it is rich or lean..

On the spark though.. aren't the cylinders paired 1/2, 3/4 and 5/6 on separate coils?I am not seeing how it could be spark:baffled:.. maybe something I am missing..

Thanks again.. al least I have a "next step" next time I take the tupperware off.. If you think of anything else, let me know.. I've ridden it for a year like this, got everything else like I want it, so time to tackle this..

SDB/Jim
 

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Yup...you are right about the coils. Was thinking about my 1200. At times I type faster than I think..if that is possible. Good catch!!
 

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redwing52 wrote:
Yup...you are right about the coils. Was thinking about my 1200. At times I type faster than I think..if that is possible. Good catch!!
I probably misunderstood what you mean here, but the 1200 coils feed 1/2 and 3/4 as well.
 

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hi jim the choke only dumps fuel into the cylinders no air as its not fireing on one bank at cold start up i would go with the choke valve blocked on that bank i know from the out side the valve is in the open position but it does not mean the fuel is getting through sea foam wont clear this as it cant get to run through the jet long enough as you prob already know the wingsdont like to be left sitting to long just to comfirm the prob the next time you have the air filter offif you can rig up a gismo iuse a hiper syringetofeed thatintake with extra fuel and see the differance
 

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agnogel wrote:
hi jim the choke only dumps fuel into the cylinders no air as its not fireing on one bank at cold start up i would go with the choke valve blocked on that bank i know from the out side the valve is in the open position but it does not mean the fuel is getting through sea foam wont clear this as it cant get to run through the jet long enough as you prob already know the wingsdont like to be left sitting to long just to comfirm the prob the next time you have the air filter offif you can rig up a gismo iuse a hiper syringetofeed thatintake with extra fuel and see the differance
Great to know this!!Next time I have theairbox cover off, I'll let in some propane from apropane torch (Unlighted, of course)to see what happens..

Can I clear the fuel passages without removing the carb (i.e. just service the enrichment valve)?
 

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I hate these carbs.

The enrichment valve is actually a carburetor within the carburetor. ...
True, I just took my spare carb apart to check this out since my memory-a fades me.

I even got my cigs out to blow smoke through the passages, but then resorted to carb cleaner.

The enrichment valve unplugs a small air port fromthe high pressure "atmosphere" side of the diaphragm sliders and also opens another port on the low pressure vacuum side.

Theend of the enrichment valve also has a pin that unplugsa fuel port coming from a jet. There is a rush of air through the port, and the vacuum such from the opened fuel port.

Your problem would be a clogged jet or a broken and stuck valve tip. The needle tip does rotate. With not fuel flow through the choke circuit, air will still be flowing. The air with no fuel will lean the F/A mixture further at idle to where combustion can not be sustained. Cold weather exaggerates the problem. With the choke off, the idle circuit goes back to normal. Vacuum gage will show the additional air flow with the choke on.

There are 4 jets in the bowl and two are threaded. The choke jet is a pressed in brass jet that is furthest from the needle seat or opposite of the main jet.

Can you remove the enrichment valve with out removing the carb? It's a goldwing, right. The problem you will have even if your could get the the valve is the linkage that is buried under the top plate. With the linkage removed, you can then further open the lever to remove the threaded valve.

(4) Would pilot screw adjustment cause (or correct) this? Seems to be fine after warmed up.
No.

Pull the carb and clean them. Then you will not have to use SeaFoam for quite long time. I am not a fan for rebuilding carbs since I have done too many others. I just take them apart, clean them, and put them back together.

Has anyone left the caps off the fuel mixture pilot screws when reinstalling these carbs?

Fun, fun, fun.
 

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Thanks Foosman.. that all jives with my experience.. I was inclined to say that there must be air passages (primarily because of RPM increase with no change in throttle plate).. but really could not confirm it.. Glad you did...

I wish there were a way to fix this without removing the carbs.. just getting to them is formidable... and the spagatti of hoses is as bad to look at in person as it is on paper..

I'll probably attempt to remove the E-valve with carb installed.. but that will be this winter...

If anyone else ahs any comments, please add them.. I've never been into the GL1500 carbs...

SDB/Jim
 

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Actually, the E-valve is in front of the carb towards the radiator. I do not really remember what is in front, but everything is so compact. Correction: The linkage does not need to be removed, but the lever needs to be in the full choke position and then the E-valve will slide out. Then, maybe you can use a straw and carb clean to try and blow to the jet.

Let us know if you find a trick to remove while installed. As you progress, you can assess if the carb needs to be removed. Also, if you take the carb apart, do remove the needle and seat. Under the seat, there is a small screen that can be overlooked.
 

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Sandy,

My '94 was doing something like that. My mechanic told me to just keep operating the "choke" lever full range, open/closed over and over and over.

He told me that it would eventually work out whatever is stopping it up. Well, it took three months of doing that every time I started the bike. But, it did just what he said it would.

I kept up the regimen after that just for grins. I would operate it full range a few times every time I start it. No more trouble after that.

YMMV
 

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Thanks John... I'll start doing that.. course here (now in Indiana), I'm just a couple weeks away from putting it away for the winter... Jim
 
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