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Goldwinger1984 wrote:
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
Hi GW1984
Thanks for this, I agree the purge valve and cannister could be replaced, the cannister appears totally free all holes in and outsuck and blow freely...[as does this problem];-)
I am scratching my head now :stumped: because if theignition unitis ignoring the vacuum advance then it can't be the purge valve causing the problem. I think more pulling off of pipes is the way to go.
thanks
BB
 

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Before you pull off more hoses Bart, double check the hoses to make sure they are not hardened and cracked at hard to see locations causing them to leak.

If you leave the vacuum hose off to the ECU you could possibly lose 5 or moremiles per gallon in fuel economy when cruising.

Vic
 

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Discussion Starter #23
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Thanks Vic!

I wonder could anyone recommend a solution for bypassing this cannister and purge valve that is practical and safe. I guess all that stuff can just be discarded? pipe the vacuum straight to the ignition unit and a t piece to the tank breather?



Thanks

BB
 

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Black Bart wrote:
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.
with the cannister pipe off, the bike is perfect 45 mpg,
1. Right, I ran like this for some time while sorting out optimum tuning. I think its actually 4th and 5th gears, its been a while... :gunhead:

2.) As I recall, yes, at least it wont affect 4/5 gears. If it does harm anything, Id hope that would consistent over the RPM range. If not, easy to put hose back on, even when riding.

3.) Cant argue with 45 mpg! Thats good as or better than averageMight just take the purge affair off and throwit in the bin?

The reason I lean towards electrics is that they cause so many strange problems that are often overlooked.
 

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Hi Bart, without having your bike in front of me, I would not want to risk advising you about modifying your fuel system due to safety factors.

What I can tell you is that your fuel tank needs overflow means and venting, the carbs need overflow and venting and the ECU needs a full manifold vacuum source signal.

Now, if you want to stop by my place I'll certainly examine the possibilities of modifying your Wing with you.

Vic
 

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Goldwinger1984 wrote:
Hi Bart, without having your bike in front of me, I would not want to risk advising you about modifying your fuel system due to safety factors.

What I can tell you is that your fuel tank needs overflow means and venting, the carbs need overflow and venting and the ECU needs a full manifold vacuum source signal.

Now, if you want to stop by my place I'll certainly examine the possibilities of modifying your Wing with you.

Vic
Hey guys, hi from the shores of Lake Superior in northern Michigan, USA. I was searching for pcv info because I just discovered that my recently purchased '85 Gl1200A has the california emissions control system on it and was hoping to find info about eliminating it. Was there any resolution to this thread's issue ... ?

My 'real' issue is actually with some roughness at low speed under no-load .... smooths out with an increase on the choke setting, or it is also better under some throttle as in uphill going in town. rpm does not seem to be a factor, as the bike runs great on the highway where I am in 4th & 5th gear at same rpm ranges as around town. The carbs are sync'd but maybe they'll need some new gaskets and o-rings this winter. The bike is low mileage but wasn't used much in the past 2 yrs since the po got a newer bike.
 

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snowy.vtwin wrote:
Hey guys, hi from the shores of Lake Superior in northern Michigan, USA. I was searching for pcv info because I just discovered that my recently purchased '85 Gl1200A has the california emissions control system on it and was hoping to find info about eliminating it. Was there any resolution to this thread's issue ... ?

My 'real' issue is actually with some roughness at low speed under no-load .... smooths out with an increase on the choke setting, or it is also better under some throttle as in uphill going in town. rpm does not seem to be a factor, as the bike runs great on the highway where I am in 4th & 5th gear at same rpm ranges as around town. The carbs are sync'd but maybe they'll need some new gaskets and o-rings this winter. The bike is low mileage but wasn't used much in the past 2 yrs since the po got a newer bike.
Hmmmm......PCV stands for "positive crankcase ventilation". NO gl1200 has it, California or otherwise.

The cannister and "excess" plumbing is for evaporitive emissions. Check your gas cap and you'll find it's plummed into the cannister to retrieve and store fuel "vapors".

Once the throttle is opened, vacuum from the Pc port allows air to be drawn through the cannister via the control valve to remove and burn the stored vapors.

All this can be bypassed by plugging the ports, isloating the cannister and installing a 49 state fuel cap........except there is no control for the evap cannister. It's a "metered" air leak.

If you check the specs, California carbs use different jets. I haven't actually seen it in print, but I suspect they are bigger to compensate for the evapsystem. If that's the case, the jets will have to be replaced as well.

Vic may be right, but there are a couple other possibilities you should check first.

Since "choking" or enrichening the mixture makes a difference, it's possible the cannister is cracked, leaking, or has come apart inside allowing too much air into the sytem. Remember, it's a "metered" air leak. Try pinching off or blocking the line from the cannister to the carbs and see if that makes a difference.
 

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Thanks guys. I have to agree that the pilot jets are the most likely problem, was just hoping I could get by without pulling those carbs off.

The pcv I was referring to was the Pilot Control Valve, it is accessible but costs over $60. The charcoal cannister and hoses are like new, I doubt there is any issue with that even though I was suspicious of the pcv. I'm pretty sure the bike has always been garage kept. All the hoses and clamps are in excellent shape. I thought about blocking the hose to the pcv but am worried that it might affect the draw of the evap from the gas cap tube.
 
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