Running LEAN


Information and questions on GL1000 Goldwings (1975-1979)
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drfrank01
Posts: 8
Joined: Wed Aug 20, 2014 9:08 am
Location: Butler, PA
Motorcycle: 78 + 79 Honda GL1000
84 BMW R100 RT SOLD
2007 BMW R1200 GSA
2006 K1200R SOLD

Running LEAN

Postby drfrank01 » Tue Sep 02, 2014 2:15 pm



I have a 79 GL 1000
First
I can't thank the guys here enough. First I got a bad carb kit from one vendor (Threw away $100) and was directed to randakk's and got a good one.
Then after a meticulous rebuild with complete cleaning and bench sync as per the instructions here and then a total carb sync using guages I got the bike to run FAIR. Also rebuilt the Air Control Valve as well.

I have very low power off idle but then it picks up pretty well as the throttle is opened more and more.
It pops at times during idle and when comming off throttle it pops and backfires a bunch.

I pulled the plugs (Brand new plugs on their first run) and they are VERY VERY LIGHT after a 15 min ride pushing it a little the whole time.

In addition I have added a K&N Air Filter to the mix but have these on all my other bikes without major problems.

I know this means LEAN mixture the point and the QUESTION is?
I would normally try to raise the needles on the carb pistons but there is no way to do that.
What if any suggestions might help with this?????

I was thinking of replacing the old air filter to see if that helps as well but I don't think that should make that much difference!


Thanks
Frank



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virgilmobile
Posts: 7660
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: Running LEAN

Postby virgilmobile » Tue Sep 02, 2014 4:22 pm

If its lean on all 4,scrutinize the "O" rings that seal the carbs to the head for leaks(vacuum) by spraying wd40 around them when running the engine.
If all is good,the next is the float level.it must be set by the book without compressing the little spring loaded pin.get them exact.
If there just 2mm off,you can run lean.
*****Test the slide action with a shop vac,sync the carbs,adjust the idle jets(idle down) .

User avatar
RBGERSON
Posts: 2625
Joined: Tue Mar 09, 2010 7:57 am
Location: SCOTTSDALE, AZ
Motorcycle: 98 SE GL 1500
had every year from 75 to 83

Re: Running LEAN

Postby RBGERSON » Tue Sep 02, 2014 4:29 pm

Note you can raise the needles with a washer a Randall talks about it somewhere on his site I don't remember the reason though. But if you are running lean I'd go back and check floats or look for vacuum leaks as suggested above and then then the mixture screw although once at speed they don't effect much only an idle thing
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

drfrank01
Posts: 8
Joined: Wed Aug 20, 2014 9:08 am
Location: Butler, PA
Motorcycle: 78 + 79 Honda GL1000
84 BMW R100 RT SOLD
2007 BMW R1200 GSA
2006 K1200R SOLD

Re: Running LEAN

Postby drfrank01 » Thu Sep 04, 2014 11:13 am

What should I notice using WD40 on the manifolds? I did this and saw no evidence of vacuum leaks.
Set the floats by tipping carbs up when I rebuilt them so that they had tension on the spring but did not compress it on the needle valve.

I rebuilt the Air Valve again with the Randakk kit and it is BETTER but not correct yet.

I drained the fuel tank and am going to check the flow through the petcock and arms within it.

Thanks for the help guys.

Frank

User avatar
HawkeyeGL1200
Posts: 918
Joined: Sat Jul 05, 2014 11:53 am
Location: Courtland, Va.
Motorcycle: 1984 GL1200 Interstate
1981 GL1100 Interstate

Re: Running LEAN

Postby HawkeyeGL1200 » Thu Sep 04, 2014 11:17 am

I was told not to use a K&N on my Goldwing, as it *could* cause it to run lean. This might be complete nonsense, but I took it off anyway.
I am wrong as often as I am right concerning what is wrong with someone else' motorcycle without having seen the machine in person. Guessing with limited information, as to the source of the trouble, is sketchy at best.

User avatar
virgilmobile
Posts: 7660
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: Running LEAN

Postby virgilmobile » Thu Sep 04, 2014 12:05 pm

Spray wd40 at a leaking seal and it will suck it in and increase the rpm.No change,no leak.
You can use a mirror in the plenum and see if the slides jump when you tweak the throttle.
Don't forget about the idle mix screws.pre-set by the book.
Don't lift the main needle(attached to the slide) it won't help the low end.
The air valve...it opens on deceleration to add a bit more fuel to the system to prevent backfiring.
If its bad,it can allow air to enter the system after the fuel ports allowing a lean run.
The carb low speed jet system provides fuel not only at the idle mix screw but to 3 tiny holes right at the edge of the throttle plate.I confided these to be a mid range fuel port.They need to provide fuel right before the main jet kicks in and after.
Soooo.fuel supply...idle jet first then 2 to 3 stages of part open throttle then all of them when its opened up.
The idle circuit covers where your having problems and 25% of the fuel above 1500 rpm then it's the main jet.
Across the board lean...I usually look for a common problem rather than all 4 carbs at fault.
Revisit any vacuum dependent system.Air cutoff,check valves,etc before you get back into the carbs.




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