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Hi Folks

The purge valve on theoffside rear of the engine is giving me some problems. It has 3 pipes connected,one large pipe to the cannister on the offside of the bike above the brake pedal. The two small pipes go to the carbs and to the vacuum advance. When the engine is revved slowly increasing the revs past 3000 the system coughs splutters and dies, only continuing to full throttle opening will make thebike rev. So we have a vacuum advance problem , if I fit a vaccumgauge to the T piece by theignition unitI canconfirm the totalloss of vacuum at 3000 revs. Now for the bit I dont understand if I remove the large pipe from the purge valve the Bike runs perfectly. Vacuum gauge confirms normal ignition advance.

There appears to be no pressure or vacuum build up in the large pipe which is effectively just a fuel fume venting system. I could replace the purge valve but could just leave the pipe disconnected and to hell with the environment.....:D

any ideas?

Thanks
 

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The Irish Crew
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It would be nice to know what model Wing this is. If its a 1500, doesn't the large pipe just go to the air filter box? If so, maybe the reed valve (not sure if that's what it's called as I own an 1100) where the pipe connects is faulty?
 

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Hi Black Bart.. This is a good one!!:? Is this a U.S. bike or a bonified import to the U.K? Looking at the diagrams in the repair manual, I don't see any of the items you are mentioning.. I've got an 86 Aspy and don't see them on my bike either. Is there any way you can take a digital pix of these items?

I just took all my intake & carbs off for a re-build & cleaning, so I can walk you thru the items to check... Also, how many miles on the bike, and is it in the original configuration? Sometimes, over the years, modifications are made that do not conform to the original systems. Hope I can help... Renegade..

By th By... Welcome to the club!!! :clapper:
 

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Thanks....:waving:



Does this picture help?

Its shows the charcoal cannister, large pipe [plugged in doesn't work, unplugged works just fine]

And you canjust about make out the purge valve



Cheers

BB
 

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Hi BB i have just looked through the 1200 workshop manual and the pipes and filter are shown fitted to the 1200LTD CALIFORNIA spec bike if that is any help i have copied the page for you but i am having trouble posting it on this forum as the file size is to big so in the meantime i will try to describe it for you-

there is a pipe from the fuel cap to the filter canister and the thicker one goes to the purge control valve, on the otherside of the canister is an air inlet hose check to see if this is blocked also there is a drain tube.

On the page it states-fuel vapour from the tank isrouted into a charcoal canister where it is absorbed and stored while the engine is stopped.

When the motorcycle is running and the purge control diaphragm valve is open fuel vapour in the charcoal canister is drawn into the engine

No adjustments to the evapourative emission control system are necessary: however periodic inspection of the hoses and canister are reccomended.

Just a thought but try running the engine with the fuelcap released slightly to see if a vacuum is being formed thereby starving the engine of fuel? it may be as simple as that. yours Malc
 

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The Irish Crew
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Is your bike a California model? Mine doesn't have this canster, only the smaller one that traps the moisture.
 

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Why not just leave the pipe off? Its similar to all the GL1100 and 1200 owners who just put a hole in the moisture collector box so it drained onto the road. I'm sure the environment will survive what puny little amount of fume gets out of your bike.
 

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Might want to check the charcoal cannister. They do get plugged up. As already mentioned the whole business with charcoal filtering etc. is a bunch of crapola anyway. Ever been downwind of a refinery?
 

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Hi Black Bart,

Recently purchased a 86 Aspen and it does the exact same thing you described with your bike. I thought it was a problem with the carbs but somewhere in the back of my little pea brain something was nagging me about the vacuum advance.

Was wondering if you ever got it sorted out.

33zip
 

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Hi 33zip

I am not running the bike over the winter so have not really progressed with the problem, there is no real performance reason why the Bike can't be run with the large pipe disconnected, there may be environmental one's though? How's your conscience? :D

Spending most of my time with bodywork, <my 1200 - no icons>paint job and suspension work, all engine maintenance is complete apart from this nagging problem, however I suspect it is the valve itself.

I can see no real reason why the canister and all its pipes cannot be stripped out and the vacuum piped straight to the manifold, but in all honesty I will solve the problem first , I just gots to know.......:weightlifter:

Will post when I find what it is



Thanks

BB
 

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I'm not making much progress with my problem either cause of the cold temp's. Don't have a heated work space for the bike and I've really been reluctant to poke around in the cold.

Thanks for getting back to me on this and good luck with your bike.
 

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Black Bart wrote:
...When the engine is revved slowly increasing the revs past 3000 the system coughs splutters and dies, only continuing to full throttle opening will make thebike rev. So we have a vacuum advance problem , if I fit a vaccumgauge to the T piece by theignition unitI canconfirm the totalloss of vacuum at 3000 revs. Thanks

Nope, the ignition unit doesnt see advance vacuum until its shifted into5th gear, its electronic till then.I ran mine often with the advance vacuum disconnected and no such problem.

Youve got electrical problems, not fuel system problems.
 

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Hi Dave

My bike runs perfectly with the pipe for thefuel vapour system disconnected, so I think my ignition system is OK. I can confirm the loss of vacuum at the ignition unit with a vacuum gauge. So I am pretty sure it is the purge valve opening that is affecting the vacuum advance draw. I believe that all engines must have some form of ignition advance at all points in their rev range, whether that is mechanical or vacuum or manually operated by the driver.

Thanks for your input into my problem as it is a perplexing one, one that is harder to discuss in a forum than it is to physically demonstrate.:D

Thanks

BB
 

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To eludicate as you requested.

It is impossible for vacuum problem to affect the ignition on a GL 1200 in gear 1-4 because the ignition system ignores the vacuum signal until the transmission switch indicates 5th gear. I tested this on an 86 Aspencade just like yours. I ran for quite a while with the vacuum advance line removed from my ICU and there was no negative effect.

The ignition unit has awire from the gear switch that toggles the ICU to vacuum advance when shifted into 5th gear. Until then, the advance is calculated by the ICU. Im not sure why it does that except possibly a fuel economy measure at top gear.

If its doing so only in 5th gear but not the rest, then Id suspect a vacuum problem is possible.

The purge valve and charcoal cannister only exist (according to my manual) on California models, which are so designated for more stringent emission requirements. Ive never seen either of them on a Goldwing. Looks like it goes to carburetors?

Id also check that reed assembly, the large rectangular blob under the manifold, it has reeds that if leaking, could do strange things by letting lots of air in the intake manifolds. I threw that deadweight in the bin and plugged off the hoses to the manifolds.

Ill still bet a pint its electrical.:action:

PS I think Vics right, it might be 4th and 5th gears. Still leaves 1-3 (1-4, whatever) that it electronic advance.
 

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Hi Bart, the ECU in 84-87 Gold Wings electronically advances timing according to rpmin the first three gears much like a mechanical advance does, then vacuum advance is added in 4th and 5th gears.

I would second exavid's recomendation of replacing the charcoal cannister and I would consider replacing the purge valve as well due to its age. (rubber seals harden with time) My biggest concern would be gasoline fumes collecting and possibly igniting if not drawn into the engine and burned.

Vic
 

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Dave Campbell wrote:
The ignition unit has awire from the gear switch that toggles the ICU to vacuum advance when shifted into 5th gear. Until then, the advance is calculated by the ICU. Im not sure why it does that except possibly a fuel economy measure at top gear.
Hi Dave

thanks for the input , If I understand correctly - there is a variable vacuum applied to the ignition unit, the ignition unit ignores this until the bike is in top gear at which point it uses the vacuum in its timing calculations.
so if this is correct and as you have confirmed I can take the vacuum advance off without any ill affects. then theoretically with all the pipes removed the bike should run just fine.
i am away at the moment but keen to get back and try the bike with all the pipes off to see how it performs , but like I say with the cannister pipe off, the bike is perfect 45 mpg, slick acceleration and smooth - keep you posted and the progress,

Thanks

BB
 
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