Rich exhaust on deceleration


Information and questions on GL1200 Goldwings (1984-1987)
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jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Rich exhaust on deceleration

Postby jtimgrant » Sun Jul 21, 2013 11:34 pm



My 87 Aspencade floods the "cab" with rich exhaust on closed throttle. I understand that is the job of the slow-air cutoff to richen the mixture upon decel but I can't believe the bike should smell this rich. This bike has run rich at idle since I bought it. I have been in the carbs at least 6 times but this rich exhaust on decel has always been present. The plugs were running very white like a lean condition but the baffles had been removed. I recently installed baffles but haven't checked the plugs since so I don't know what they look like. I have checked all the plug caps and they are within specs. The wires look like the original ones or at least they are OEM.

Any ideas about this rich condition?

Thanks

Tim



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virgilmobile
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Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
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Re: Rich exhaust on deceleration

Postby virgilmobile » Mon Jul 22, 2013 2:53 pm

When you were in the carbs,did you remove the protective caps over the idle mixture screws and reset them?
Also,could someone have forgotten the spring that sets on the valve that keeps it closed while running?

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Mon Jul 22, 2013 10:09 pm

Hi Virgilmobile. The spring is in place and I did set the pilots.

I have learned something new today. Number 1 cyl died so I pulled the carbs. I found no trash so I decided to try an experiment. Until I bought the bike in May it had not been licensed since 2008 so it has set up a while.I am thinking the needle valves have hardened and are not sealing. So, I set the floats at the factory setting of 7.5mm but this time with the carbs turned upside down allowing the weight of the floats to rest on the needle valve plunger. The honda manual says to set the floats with the tang on the float just touching the plunger but I am thinking the needles aren't shutting the gas off and the fuel pump pressure is overcoming the needles. When I started the bike back up number 1,2,4 were good but number three was dead. So I pulled the carbs again and found no gas in the number 3 bowl though all the floats were set the same. I figured this needle was working so I reset just number 3 to the factory specs and the cyl came back online. This setting almost completely stopped the rich condition with very little rich exhaust at any time including upon deceleration.

So, then . . . it seems I need a set of needles.

Does this make sense to you?

Tim

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virgilmobile
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Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
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83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Rich exhaust on deceleration

Postby virgilmobile » Mon Jul 22, 2013 10:47 pm

Sounds good.
While you wait for avaiable funds and shipping,here's something you can do in the down time.
Remove the carbs and properly decontaminate them inside.
While there soaking,remove the brass needle seat,use a "Q" tip with your favorite brass cleaner,chuck it in a battery drill and polish the needle seat.
Take the needle and clean it then polish the 3 ridges with 3000 grit paper.I clean the rubber tip with alcohol.
Clean the float pivot pin with the paper too.
Check the spring loaded pin in the bottom of the needle,I've seen them stuck.
Reassemble,tilt the carb till the float just rests against the needle without compressing it.
Adjust the "tang" as necessary to set the float exactly by the book.front,rear and side to side.

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Tue Jul 23, 2013 9:00 am

Sounds like a plan. I will pull it back down tonight and take a much closer look at these parts. Cleaning the tips with alcohol makes sense as does polishing the seats. I'm thinking there may be a coating or glaze on the tips and seats from setting up. I was hoping to salvage the needles and seats, especially after looking at Bike Bandit's price of $46 per set for OEM. I need to shop around. Know any good source for needles while I wait? Would you use new needles in the polished seats? I have to pull the exhaust and replace the gaskets since it leaks and probably adds to the exhaust smell so I have some time.

Thanks much for the help. This forum is a great help both in time and sanity! And that's saying a lot for my insane self.

Tim

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virgilmobile
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Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Rich exhaust on deceleration

Postby virgilmobile » Tue Jul 23, 2013 9:35 am

I have never needed to replace a single part inside any of my carbs with the exception of one broken bowl gasket.
At least on the last 14 carbs I serviced,I just polish all the varnish off and ensure no binding in the float or needle movement and its spring loaded pin.
The rubber tip on the needle can be cleaned.If its hardened,I resurface it with 3000 grit paper or use rubber renew compound.
As always,I test the carbs on the bench first.Fill with gas,a container 4' above it.
Set the throttle plates for a pre-sync and vacuum each carb to test the slides.

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Tue Jul 23, 2013 12:00 pm

Sounds good to me! I will do the polishing of needles, seats and renew tips. I do think that varnishing is the problem but I did not know the tips could be refurbished. See, you can teach an old dog new tricks.

How do you vacuum the slides? I was wondering about how to test them on one of the other many occasions I had the carbs apart. And when you test the floats what are you looking for? Anything besides leakage? Do you measure the amount of fuel in each bowl. I have read that some folks do measure for assurance of equal levels.

Tim

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virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Rich exhaust on deceleration

Postby virgilmobile » Tue Jul 23, 2013 3:12 pm

I sparingly use a liquid call rubber renue from MG chemicals,or acetone(finger nail polish remover) on the needle tip then clean with a micro cloth or fine paper.
Do not use Brake cleaner..It will eat the rubber.

As far as the floats,I assemble with the bowls left off,tilt the carb till the float just touches the needle pin..There I'm going to measure the float distance...It must be dead accurate..Not only on one part but in every direction,front to back and side to side...Bend the mount and tang as necessary.

I fill the carbs with fuel by a container 4'-5' above the carbs (simulates a fuel pump) wait a few minutes to check for flooding...If all is good,I drain each one into a glass and measure each one for the same amount.

After complete assembly,I simply hold the hose of my cheap shop vac to each tube...Operate the throttle and watch how far the slide rises...I compare it to each one...I look for smooth moving without sticking.
Finally a pre-sync then a final vacuum sync on the bike.

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Tue Jul 23, 2013 7:44 pm

Ok. I'll give it a go. let you know what I find. Thanks!

Tim

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Sun Jul 28, 2013 3:34 pm

Ok. Pulled and cleaned needles and seats. Set float levels. Filled carbs and measured gas in each bowl. Each has exactly same volume. Runs perfect on road. Pulls hard. No rich smell at idle. So the rich running problem is gone! But I still have rich exhaust upon hard decel - that is riding at 60 and just closing the throttle. If you decel slowly, that is half closing throttle and the dropping slowly there is no rich smell. I looked for an exhaust leak but cannot find one even though the exhaust sounds ragged to me. I seems something in the afterburn system or slow air valve must the the culprit but I'm a real novice on these two systems. There are no vacuum leaks in the system. I'm baffled. Any ideas?

BTW: Again, thanks for the help. The needle and seats NEEDED polishing - big time. Also, the guides along the side of the needle were rough too. The rubber seals on the needles looked good so I just cleaned them all up. This bike runs perfect now except for the rich exhaust smell on decel.

Tim

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Mon Aug 12, 2013 5:17 pm

I waited to follow-up on the last carb work until running the bike some. It ran perfect! Starts instantly cold without choke. Never ran this good. Smooth. But this is at highway speeds. Today I took it up to the Blue Ridge and cruised along about 45mph in 5th gear. Rpm's ran steadily below 2500. I noticed as I ran along the motor continued to get richer - especially when decelerating. When I left home the bike was smooth and idle was 1060 rpm where it usually runs. By the end of the ride the bike sounded more like a John Deere and running at 940 to 960 rpms. I pulled the plug wires and the motor changes with each wire pulled but 3 runs weaker than the rest. The problem seems to be fuel related since each time I remove the carbs a clean them it runs great for a while.

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Tue Aug 13, 2013 8:08 pm

Well removed the carbs . . . again. Found no trash in bowls. Same amount to gas in each. So, removed jets and flushed every orifice I could find with Berryman 12 and compressed air until cleaner flowed freely out as fast as I put in. If this doesn't fix this problem I think I will part it out. :lol:

jtimgrant
Posts: 77
Joined: Sat May 25, 2013 7:24 am
Location: Greensboro NC.
Motorcycle: 1987 GL1200 Aspencade

Re: Rich exhaust on deceleration

Postby jtimgrant » Wed Aug 14, 2013 1:48 pm

Got it back together. Started it up, sync'd carbs, adjusted pilot screws. Still runs rich on 1 & 3 at idle. Plugs are a little wet. Motor idles up when carb sync screw on # 3 is removed implying too much gas I suppose. I checked the timing marks again a couple weeks ago and all marks were spot on so I doubt its timing related. Runs smooth off idle. Also had to crack the throttle to start it when warm and got a loud backfire on right exhaust. Too much fuel collecting in exhaust? Wants to over fuel on the right side or firing is weak. New caps and plugs. Wires have not been replaced. Baffling.




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