low vacuum reading on carb synch


Information and questions on GL1200 Goldwings (1984-1987)
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tombyers
Posts: 14
Joined: Fri Dec 16, 2011 7:43 pm
Location: fort myers fl
Motorcycle: 1984 GL 1200

low vacuum reading on carb synch

Postby tombyers » Thu Apr 26, 2012 4:50 pm



I have a 84 Goldwing with 40k miles and 115-120 compression and am getting low vacuum reading on my #4 carb. It typically reads about 12. Motorcycle dosen't smoke but has to be ridden with choke partially on and sputters at low rpm's. I took carbs off and found the slow jets to be partially clogged. Dealer did not have any #35 slow jets in stock so I bought four #58 slow jets as an experiment but this just made it worse.



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vtxcandyred
Posts: 517
Joined: Thu Dec 31, 2009 5:08 pm
Location: Oregon, Ohio
Motorcycle: 1993 Honda Goldwing SE

Re: low vacuum reading on carb synch

Postby vtxcandyred » Thu Apr 26, 2012 6:01 pm

tombyers wrote:I have a 84 Goldwing with 40k miles and 115-120 compression and am getting low vacuum reading on my #4 carb. It typically reads about 12. Motorcycle dosen't smoke but has to be ridden with choke partially on and sputters at low rpm's. I took carbs off and found the slow jets to be partially clogged. Dealer did not have any #35 slow jets in stock so I bought four #58 slow jets as an experiment but this just made it worse.

Try a local mom and pop type of bike shop. We have a small one here and he carries most of the things you would need like that. If you can't find them let me know and I'll stop by and see if he has any. I know I can put them in a regular envelope and mail them to you. By the way, have you checked the other miriad of vacumn lines on your scoot?????

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skier
Posts: 154
Joined: Sun Jul 17, 2011 11:57 am
Location: Coon Rapids MN
Motorcycle: 1987 GL1200I 124k
2009 Honda Silverwing 14k -- the wife's scooter

Re: low vacuum reading on carb synch

Postby skier » Fri Apr 27, 2012 10:47 pm

Those compression numbers seem on the low end of acceptable.

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Mooseman
Posts: 383
Joined: Thu Sep 10, 2009 11:10 am
Location: Napa, CA
Motorcycle: 1996 GL1500SE 88k
1986 GL1200A (SOLD) 81K
1985 GL1200A (SOLD) 85K
1986 BMW K75c 25K

Re: low vacuum reading on carb synch

Postby Mooseman » Sat Apr 28, 2012 11:56 am

Take your slow speed jets and soak them in carb cleaner and then blow them out with compressed air. Also check those passages in the carb to make sure they are clear. Check my photos to see which ones were clogged on mine. Going with the diffrent jet sizes will effect how it runs.
The low vacuum at #4 could be from a vacuum leak or a pinched O ring when it was put back together. If you have a propane tourch. Try putting a little propane around the intake tube and see if you get any change in engine RPM. You can also use carb cleaner and spray it around the fitting and check for changes.
As far as the Compression readings? Done cold or with a warm engine? Also depending on the type of gauge used and how connected.
Also more important than the vacuum readings is to have all 4 close together in their readings. #4 is non adjustable and is the base for the others. If the others are off it can cause #4 to read low. If there are no leaks and good compression you should be able to sync the carbs to be equal. That and clean carbs will make your machine run like a champ.


Enjoy the ride. They are all good, just some better than others.
Mooseman


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