1975 GL1000 flooding rough running


Information and questions on GL1000 Goldwings (1975-1979)
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carnuttgl1000
Posts: 3
Joined: Tue Jun 22, 2021 6:22 pm
Location: Riverdale, NE, United States
Motorcycle: 1975 GL1000

1975 GL1000 flooding rough running

Post by carnuttgl1000 »



Okay this is taking a role on me. Have a 1975 GL1000 that I just rebuilt the carbs and adjusted the floats per spec at 21mm height and installed them to start bike for the first time. Bought bike used had been sitting for years 13k on it. New plugs verified good spark on all cylinders but it only seems to run on 1 cylinder. Meaning #4 is the only one getting heat out exhaust. EGT temp runs about 500-650 F while both 1&3 are stone cold at below 250 and they is a lot of raw fuel smell and smoke out that header. ( yes open headers for now). Cylinder 2 has some heat but much colder at 350 or so? What’s up?


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Maz
Posts: 806
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: 1975 GL1000 flooding rough running

Post by Maz »

If the carbs are flooding, you likely have a problem with the needle valve seats. Did you measure the float height with the floats just touching the needle spring NOT compressing it. This is easier to measure with the carbs standing on end. When you replaced the floats, did you check the tips of the needles? They are rubber tipped and the rubber can go rock hard over time. They need to be clean and smooth with no wear ridge.
Likewise, the needle seats need to be scrupulously clean. These can be polished with a q tip and some metal polish or fine valve-grinding paste. Wash thoroughly with fuel afterwards. Check the valve operation by blowing through the fuel inlet pipe with the carbs up the right way, then invert them and blow again. You shouldn't be able to blow through at all with the carbs upside down.
Also, check the little spring in the end of the needle that touches the float 'tang'. Sometimes these jam in the compressed condition.
Maz
Ironically, Common Sense is the LEAST common of all senses!
carnuttgl1000
Posts: 3
Joined: Tue Jun 22, 2021 6:22 pm
Location: Riverdale, NE, United States
Motorcycle: 1975 GL1000

Re: 1975 GL1000 flooding rough running

Post by carnuttgl1000 »

Carbs were rebuilt with new seats and needle valve. Yes floats were checked with the carb sitting vertical. I think I had them adjusted wrong first time around. Could possibly be faulty new parts or cheap bad seats I guess. Will check for the air test on fuel inlet. If carbs are adjusted correctly say, would low compression or valves not adjusted right be an issue?

Going try cold valve adjust first and then check compression and do a leak down. Thanks.
carnuttgl1000
Posts: 3
Joined: Tue Jun 22, 2021 6:22 pm
Location: Riverdale, NE, United States
Motorcycle: 1975 GL1000

Re: 1975 GL1000 flooding rough running

Post by carnuttgl1000 »

Found it! Valves were adjusted too tight. So that with the fact I flooded it and fuel washed the cylinders wasn’t helping. Put fresh oil in and adjusted the valves now it runs!
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Maz
Posts: 806
Joined: Tue May 19, 2015 4:43 am
Location: Kent, UK
Motorcycle: 1975 GL1000K1
1976 CB500T
1979 CB750L
1990 Yamaha FJ1200
1993 Suzuki GS500E

Re: 1975 GL1000 flooding rough running

Post by Maz »

Glad you got it sorted.
Maz


Ironically, Common Sense is the LEAST common of all senses!
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