Single Carb Help


Information and questions on GL1000 Goldwings (1975-1979)
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PhillGrip
Posts: 1
Joined: Wed May 20, 2015 2:12 pm
Location: Charlotte, NC
Motorcycle: 1978 GL1000 "Naked Wing"

Single Carb Help

Postby PhillGrip » Thu May 21, 2015 6:47 pm



Hello fellow Goldwingers. I have a 78 GL1000 that has a Holley 1940 single barrel carb on it. It drives and performs great, but it runs super rich. So rich that at a stop while idling between 1 and 2 it shoots the occasional fireball from both of the mufflers, and sometimes a constant flame from the right side muffler only. I've tried adjusting the choke and throttle screw to various settings all ending with the same result, so I set it in the position where the bike performed the best. I'm thinking replace the floats as they are old and rejet the carb to something smaller, but I have no clue what size jets to get. Any suggestions?
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Phillip Gripper
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redbug
Posts: 256
Joined: Fri Sep 30, 2011 8:22 am
Location: Broken Arrow,Ok
Motorcycle: 1983 Gl1100I
1986 Harley FLHT

Re: Single Carb Help

Postby redbug » Thu May 21, 2015 7:27 pm

Is that air filter dirty? Pull it off and see if it changes the idle. Just curious, adjusting the idle mixture screw will not clear the problem up? Do I see a open tube vacuum port on the carburetor? If it is, press the end of you finger over the brass port tube and see also if it idles better. Really need more info. Also check for vacuum leaks around the base of the carburetor using wd 40 and throw a wrench on the carb mounting bolts to be sure they are snug. What do the plugs look like? Hope this helps and welcome to the site.
" Ridin on Tulsa Time "

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roadwanderer2
Posts: 4111
Joined: Thu Aug 08, 2013 4:03 am
Location: sweetwater, Tennessee
Motorcycle: 83 GL1100A aspencade, previously owned, 1981 honda GL500i silverwing interstate, 1974 yamaha xs400, 1974 Honda cb450 twin cam, 1983 honda vt30, 1982 honda 700 shadow, 1972 cb750four, and my first bike, a brand new 1982 honda CM400e. and a new to me 1986 GL1200 aspencade SEi
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Re: Single Carb too rich

Postby roadwanderer2 » Fri May 22, 2015 3:52 pm

just a thought here, but what i would do other than going back to stock carbs, is take that carb off and take it to a shop that does carb rebuilding, tell them what's going on with it and how its acting on your bike. and let them tear it apart and rebuild it, that way it will be professionally rebuilt and you shouldn't have any more problems with it.

stuart.

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redbug
Posts: 256
Joined: Fri Sep 30, 2011 8:22 am
Location: Broken Arrow,Ok
Motorcycle: 1983 Gl1100I
1986 Harley FLHT

Re: Single Carb too rich

Postby redbug » Fri May 22, 2015 4:16 pm

Is that air filter dirty? Is that a vacuum port open, the brass tube? Have you tried adjusting the idle mixture screw? Have you sprayed around the carburetor with wd-40 checking for vacuum leaks? Have you check all the carb and intake bolts and nuts to see that they air tight and sprayed wd-40 in those areas? I would do the idle mixture screw first to see if the idle clears up, then pull the air filter to see if idle changes. Check that brass tube to see if it is pulling vacuum, cap it or find the hose that went to it.
" Ridin on Tulsa Time "

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robb
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Joined: Mon Jul 19, 2010 7:46 pm
Location: Lexington, North Carolina
Motorcycle: 1989 Honda GL1500 Aspencade

Re: Single Carb too rich

Postby robb » Fri May 22, 2015 5:20 pm

The main jet is definitely too large, maybe 2 sizes. Float should be OK, but it never adjusted I would not change. Jets are 5-6 dollars each. If you have to order jets I would suggest get 3 jets less than you currently run. Try the middle jet and if rpm needed is 1200 keep going down, but if its too low you can go up.
I prefer a single carb whenever possible for bottom end torque gains. Less shifting at low speeds.




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