Early gl1000 carb Interchangeability


Information and questions on GL1000 Goldwings (1975-1979)
Post Reply
jtcr85@gmail.com
Posts: 7
Joined: Wed Aug 14, 2019 6:07 am
Location: australia tas
Motorcycle: 1975 gl1000

Early gl1000 carb Interchangeability

Post by jtcr85@gmail.com » Fri Jan 31, 2020 12:16 am



So the early to late carbs don’t swap so well, even though they all bolt on ok, but How interchangeable are the 1975 and 1976 Goldwing carburettors?
I’ve searched online, and can’t find any info, and I can’t find any threads on this forum about it, but if anyone knows of any please link me to it.
I am considering buying an old set of 1976 carbs off a bloke numbered 758A instead of the 1975 755A carbs that should be on my bike, and he reckons that the difference between the years is only a Couple of replaceable jet needles, this a 758 carb can be turned into a 755 with just a few needle changes.
Has anyone got any experience trying to swap early carbs?
Thanks



heli_madken
Posts: 8
Joined: Tue Feb 12, 2019 7:51 am
Location: United Kingdom
Motorcycle: 1977 GL1000 K2

Re: Early gl1000 carb Interchangeability

Post by heli_madken » Fri Jan 31, 2020 7:25 am

Hi There is some good information here on Randakks blog https://www.randakksblog.com/early-vs-l ... b-specs-2/

The only difference I can see between the 758A and 755A is the primary main jet and matching CV needle, there may be a difference in the shape of the CV slide. I dont think there is any difference in valve operation between 1975 and 1976 models so I should have thought you would see very little difference in performance.

I have a set of 755A carbs on a 1977 bike which should have 764A and the bike runs great now having solved some issues such as a leaking plenum seal. I think for this range of models its more important that the carbs are in perfect operating condition, there maybe some performance differences as the Honda engineers where chasing more low down torque but they should operate fine.

User avatar
ekvh
Posts: 403
Joined: Thu Apr 29, 2010 9:52 am
Location: Grand Forks, ND
Motorcycle: 1977 gl1000

Re: Early gl1000 carb Interchangeability

Post by ekvh » Fri Jan 31, 2020 7:09 pm

They are virtually the same , but differences are enough not to mix parts. The only nod some give to the 75 carbs were the scalloped base of the slides. They had slightly bigger jets as a result. Some felt the 75’s were better at WOT.

75-77’s all suffered anemic off idle response from the factory. Changing the idle air jet to slightly smaller helps immensely. Randakks has as good a write up as you’ll find.

heli_madken
Posts: 8
Joined: Tue Feb 12, 2019 7:51 am
Location: United Kingdom
Motorcycle: 1977 GL1000 K2

Re: Early gl1000 carb Interchangeability

Post by heli_madken » Sat Feb 01, 2020 2:50 am

ekvh wrote:
Fri Jan 31, 2020 7:09 pm
75-77’s all suffered anemic off idle response from the factory. Changing the idle air jet to slightly smaller helps immensely. Randakks has as good a write up as you’ll find.
I personally think this depends on where you are in the world in terms of altitude, my bike has the original idle air jets and I get no sense at all of the off idle stumble, I am in the UK only a couple of hundred feet above sea level. If your bike doesn't suffer this leave it alone

jtcr85@gmail.com
Posts: 7
Joined: Wed Aug 14, 2019 6:07 am
Location: australia tas
Motorcycle: 1975 gl1000

Re: Early gl1000 carb Interchangeability

Post by jtcr85@gmail.com » Wed Feb 12, 2020 4:48 am

thanks for the info, i ended up buying the non 755 carbs off a 76 so ill give em a go!



Post Reply