Syncing carbs...again


Information and questions on GL1200 Goldwings (1984-1987)
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twocams
Posts: 554
Joined: Tue Sep 29, 2015 11:25 am
Location: Grants Pass, Oregon
Motorcycle: 1985 GL1200 Aspencade, 2003 K1200GT BMW, 1969 R69S BMW
Sold : 84 V65 Magna, 82 Moto Guzzi, XS 1100 Yamaha,84 Wing Int., 80 650 Special, Only new bike 82 XV750 Virago (Guam),Honda 250,84 R100RT BMW,87 K100 LT BMW,93 K1100 LT BMW, 91 535 Virago, Honda 50

Syncing carbs...again

Postby twocams » Fri Jan 01, 2016 10:47 pm



I have read just about every forum about the synchronization of the Gl1200 carbs. But most are on the 1000 and 1100. And cant find much on the 85 GL1200A. Which has the metal arms that attach to carb #4 & #3 and attaches to the cable wheel.
#4 is the fixed carb. But every time I try to adjust #3 carb I loose vacuum from say 10 down to 5in. Even increasing the engine speed with idle screw opens the butterfly on #4 and loose vacuum.
So what gives/what im doing here? :x


Twocams



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deanbw
Posts: 278
Joined: Sun Nov 30, 2014 2:30 am
Location: puyallup,wa.
Motorcycle: 1986 gl1200a aspencade . Honda xl600r, '68 z50, '82z50, '80cx500c, '00 klr250

Re: Syncing carbs...again

Postby deanbw » Sat Jan 02, 2016 12:41 am

ok well, first warm engine to normal operating temp by running about 10 minutes. remove synch screws in manifolds and install tubes. start engine, adjust idle to 1000. start on left side (2&4), synch those carbs to each other. Now go to right side (1&3), synch those carbs to each other. You should check idle after you sync each side and keep it adjusted to 1000. Don't worry about numbers (inches of vacuum) just synch left carbs to themselves and right carbs to themselves. Now you go to the back of the rear - right carb (3) and synch the left side to the right side.
That should do it, if you have no pulled jets or vacuum leaks.
best of luck -

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deanbw
Posts: 278
Joined: Sun Nov 30, 2014 2:30 am
Location: puyallup,wa.
Motorcycle: 1986 gl1200a aspencade . Honda xl600r, '68 z50, '82z50, '80cx500c, '00 klr250

Re: Syncing carbs...again

Postby deanbw » Sat Jan 02, 2016 1:35 pm

I should mention just to make sure we are on same page that to sync left side to it self and right side to it self you use the adjusting screws between the carbs, then when you adjust the left and right sides to each other you use the adjusting screw on the rear of the number 3 carb (the metal arm )
I also noticed in your picture it looks like you only have one cable on the throttle pull, not a big deal, the push side is only there as a safety on street bikes, they aren't used on dirt machines.

User avatar
twocams
Posts: 554
Joined: Tue Sep 29, 2015 11:25 am
Location: Grants Pass, Oregon
Motorcycle: 1985 GL1200 Aspencade, 2003 K1200GT BMW, 1969 R69S BMW
Sold : 84 V65 Magna, 82 Moto Guzzi, XS 1100 Yamaha,84 Wing Int., 80 650 Special, Only new bike 82 XV750 Virago (Guam),Honda 250,84 R100RT BMW,87 K100 LT BMW,93 K1100 LT BMW, 91 535 Virago, Honda 50

Re: Syncing carbs...again

Postby twocams » Sat Jan 02, 2016 2:08 pm

Thanks deanbm,
Ill give it a try, yabut today is a day of rest. And maybe tomorrow as well.

User avatar
twocams
Posts: 554
Joined: Tue Sep 29, 2015 11:25 am
Location: Grants Pass, Oregon
Motorcycle: 1985 GL1200 Aspencade, 2003 K1200GT BMW, 1969 R69S BMW
Sold : 84 V65 Magna, 82 Moto Guzzi, XS 1100 Yamaha,84 Wing Int., 80 650 Special, Only new bike 82 XV750 Virago (Guam),Honda 250,84 R100RT BMW,87 K100 LT BMW,93 K1100 LT BMW, 91 535 Virago, Honda 50

Re: Syncing carbs...again

Postby twocams » Sat Jan 02, 2016 2:29 pm

So maybe Im doing this a little wrong. We are just using the center screws between the carbs to sink each other. Then for left to right we are just using the outer screw on #3 to adjust to #4? makes sense kinda what I was dong. Old saying " same thing only different". Yes that cable is disconnected for now. Was a bit tight, thought it might be hampering my adjustments. I'll losin a bit and re hook after.
Thanks for the help dean
Twocams

User avatar
deanbw
Posts: 278
Joined: Sun Nov 30, 2014 2:30 am
Location: puyallup,wa.
Motorcycle: 1986 gl1200a aspencade . Honda xl600r, '68 z50, '82z50, '80cx500c, '00 klr250

Re: Syncing carbs...again

Postby deanbw » Sat Jan 02, 2016 10:47 pm

twocams wrote:So maybe Im doing this a little wrong. We are just using the center screws between the carbs to sink each other. Then for left to right we are just using the outer screw on #3 to adjust to #4? makes sense kinda what I was dong. Old saying " same thing only different". Yes that cable is disconnected for now. Was a bit tight, thought it might be hampering my adjustments. I'll losin a bit and re hook after.
Thanks for the help dean
Twocams


Yes sir, the screw between the carbs to adjust those two carbs to them selves, then the screw on back of no.3 to adjust the left set to the right set




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