G'day to All,
i am having trouble getting my GL-1000 to run smoothly under 2500 to 3000 rpm, i have had the carbs out and in a dozen times, she runs good and plenty of grunt above 3000 rpm, but under that she seems to be running out of fuel as you just amble along at say 70Km/Hr.
Over the years i have had many carbs to bits and i am just wondering if i have mixed the piston springs up and have a set of 75-77 springs in there instead of the 78-79 ones?
Maybe someone could enlighten me
I have the spring on the Left fitted into my 1978 769A carbies.
Thaks in advance, Peter
78 GL-1000 769A carbie piston springs ???
Moderators: CYBORG, Oldewing, robin1731, Forum Moderators
- Pedrotq
- Gold Member
- Posts: 1072
- Joined: Tue Dec 03, 2013 3:04 am
- Location: Perth, Western Australia
78 GL-1000 769A carbie piston springs ???
- Attachments
-
- 101_1457.JPG (198.66 KiB) Viewed 155 times
Pedrotq ~ (Pedro The Questionable)
Perth, Western Australia.
1988 GL-1500 ~ HRD sidecar outfit.
1990 GL-1500SE ~ (project) ~ Stripped down to be a "Naked 90".
Perth, Western Australia.
1988 GL-1500 ~ HRD sidecar outfit.
1990 GL-1500SE ~ (project) ~ Stripped down to be a "Naked 90".
- Whiskerfish
- President
- Posts: 36949
- Joined: Thu Feb 16, 2006 9:34 pm
- My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
- Location: Norfolk Va
Re: 78 GL-1000 769A carbie piston springs ???
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
"Yea I do dance awkwardly, and I am having more fun than you" Taylor Swift
2008 GL1800 IIIA "TH3DOG"
1984 GL1200 Standard
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
Psst. oh and by the way CHANGE YOUR BELTS!!!!
"The book is wrong, this whole Conclusion is Fallacious" River Tam
"Yea I do dance awkwardly, and I am having more fun than you" Taylor Swift
2008 GL1800 IIIA "TH3DOG"
1984 GL1200 Standard
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
Psst. oh and by the way CHANGE YOUR BELTS!!!!
-
- Gold Member
- Posts: 1128
- Joined: Tue Jun 02, 2020 8:39 am
- Location: NW Indiana,
Re: 78 GL-1000 769A carbie piston springs ???
One other thing I would check is the idle circuit as it is the main fuel supplier up to about 2200rpm. If you pull the carbs, then sand the red plastic tube from your gumout can down to a taper, then put the taper into the idle jet and spray (protect your eye’s & face) you should have gumout come out of the idle mixture screw hole with the screw removed and the idle discharge hole in the throttle bore with the screws installed. If no fluid comes out & I’d bet it won’t, you have a plugged idle mixture circuit.
Now while whiskerfish’s excellent photo in his attachment shows the spring differences in the various year carbs and you have the wrong springs in your 78, these really shouldn’t come into play until around 2200-2400rpm.
And without knowing the spring rates when the main slide/needles start to move/open and add fuel you should have a bog from the slides not opening (springs to stiff) or from the slides banging open to quickly (springs to light) . The slide movement is created by the air rushing through the bore and under the slides where the communication holes on the slide bottoms create a vacuum on the top that lifts the slides. The 78/79’s have slightly smaller bores than the 75-77’s which increase the slide vacuum signal so I’m thinking the 78/79 springs are stiffer than the 75-77 springs you have installed. So your slides are opening to quickly (my opinion).
Anyway put the right springs in so the slides work right but I’d also make sure the idle circuit is clear with some carb cleaner. My.02
Now while whiskerfish’s excellent photo in his attachment shows the spring differences in the various year carbs and you have the wrong springs in your 78, these really shouldn’t come into play until around 2200-2400rpm.
And without knowing the spring rates when the main slide/needles start to move/open and add fuel you should have a bog from the slides not opening (springs to stiff) or from the slides banging open to quickly (springs to light) . The slide movement is created by the air rushing through the bore and under the slides where the communication holes on the slide bottoms create a vacuum on the top that lifts the slides. The 78/79’s have slightly smaller bores than the 75-77’s which increase the slide vacuum signal so I’m thinking the 78/79 springs are stiffer than the 75-77 springs you have installed. So your slides are opening to quickly (my opinion).
Anyway put the right springs in so the slides work right but I’d also make sure the idle circuit is clear with some carb cleaner. My.02
Red 1976 oe owner
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
1976 LTD restored
1980 CBX , in the que, to fix the ignorant heavy handed owner
1981 CBX
1977 CB750 K7
2014 FJR OE owner, sold
1980 GL1100
1984 GL1200 naked
1969 CL350, in the que
- ericheath
- Honored Life Member
- Posts: 9581
- Joined: Wed Jul 29, 2009 11:20 am
- Location: Winnipeg, Manituba
Re: 78 GL-1000 769A carbie piston springs ???
The 78-79 springs which were in one set of 764A (77) carbs were much weaker than the longer 75-77 springs. (I must have four sets of 764A carbs) Weaker springs will lift with less vacuum and fuel will come on faster.
I can’t say whether the springs were different rates. I believe the number of coils are the same. I use Octane’s suggestion for comparing springs and slides which is in Shoptalk in his carb rebuild tutorial. You can at least confirm that they are close. Using Octane’s method of inverting the cap and measuring how far the slide’s weight compresses the spring, the 78-79 springs in mine, pushed the slide all the way down in the inverted cap.
If you have one of the four springs different from the others, it’ll probably run like crap.
I can’t say whether the springs were different rates. I believe the number of coils are the same. I use Octane’s suggestion for comparing springs and slides which is in Shoptalk in his carb rebuild tutorial. You can at least confirm that they are close. Using Octane’s method of inverting the cap and measuring how far the slide’s weight compresses the spring, the 78-79 springs in mine, pushed the slide all the way down in the inverted cap.
If you have one of the four springs different from the others, it’ll probably run like crap.
Whatever I suggest here should be given ample time for a moderator to delicately correct. I apologize in advance.
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
77 WING, 1200 engine with 77 heads, cams, gl1100 foot pegs, Magna V65 front end, 764A carbs, [-gone Suzuki M109 monoshock--, replaced with gl1100 shocks] gl 1200 swing arm, gl1500 final drive, wheel and rear brakes Valkyrie seat, Meanstreak tank, Sportster pipes, Power Arc ignition off crank.
77 Wing. black
83 Wing, in pieces
"Continuing education is important even if the subject matter is fairly useless (as in this case)."---Greg Foresi
- gltriker
- Honored Life Member
- Posts: 5064
- Joined: Fri Sep 24, 2010 9:11 pm
- Location: central NY State
Re: 78 GL-1000 769A carbie piston springs ???
quote-" i have had the carbs out and in a dozen times,"
Risking sounding ridiculous, are all of the fuel bowl retaining screws and their complementing carburetor body screw threads in very good condition after so many carburetor disassemble/reassemble sessions?
Securely clamping the fuel bowl gasket onto the carburetor body where it covers the aluminum puck and seals the idle circuit passages is my concern.
Risking sounding ridiculous, are all of the fuel bowl retaining screws and their complementing carburetor body screw threads in very good condition after so many carburetor disassemble/reassemble sessions?
Securely clamping the fuel bowl gasket onto the carburetor body where it covers the aluminum puck and seals the idle circuit passages is my concern.
Cliff (74yrs )
Keep your eyes and ears open and you'll learn something new, everyday.
New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^
RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi
"Can't see the paint when your looking thru the handlebars..........." -Oldewing
"I'd rather Ride than Shine" -RAT Me Too!!
Cliff
'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM https://nakedgoldwingsclub.com/forum/page/Welcome
previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
Keep your eyes and ears open and you'll learn something new, everyday.
New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^
RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi
"Can't see the paint when your looking thru the handlebars..........." -Oldewing
"I'd rather Ride than Shine" -RAT Me Too!!
Cliff
'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM https://nakedgoldwingsclub.com/forum/page/Welcome
previous rides:
1953 H-D Servi-car, naked, 1969-1978 (serial#53G1559 committed to memory!)
1980 CB900 Custom (triked) 1997-2003 .... R.I.P.
- Pedrotq
- Gold Member
- Posts: 1072
- Joined: Tue Dec 03, 2013 3:04 am
- Location: Perth, Western Australia
Re: 78 GL-1000 769A carbie piston springs ???
Thanks so much for the help guys
I did have all the piston springs wrong, had the longer 75 ~ 77 springs installed. I have many spares and the correct ones are now fitted.
The carbs have been cleaned a few times, all passageways clear, new OEM Honda needle and seats, all OEM jets and needles, Randakk's "O" ring kits fitted and all bowl threads have been Helicoiled.
I am sure she will run better now
Happy and Safe Riding to All, Peter
I did have all the piston springs wrong, had the longer 75 ~ 77 springs installed. I have many spares and the correct ones are now fitted.
The carbs have been cleaned a few times, all passageways clear, new OEM Honda needle and seats, all OEM jets and needles, Randakk's "O" ring kits fitted and all bowl threads have been Helicoiled.
I am sure she will run better now
Happy and Safe Riding to All, Peter
Pedrotq ~ (Pedro The Questionable)
Perth, Western Australia.
1988 GL-1500 ~ HRD sidecar outfit.
1990 GL-1500SE ~ (project) ~ Stripped down to be a "Naked 90".
Perth, Western Australia.
1988 GL-1500 ~ HRD sidecar outfit.
1990 GL-1500SE ~ (project) ~ Stripped down to be a "Naked 90".
-
- Similar Topics
- Replies
- Views
- Last post
-
- 3 Replies
- 127 Views
-
Last post by ericheath
-
- 14 Replies
- 524 Views
-
Last post by Dr. Frankenstein
-
- 6 Replies
- 213 Views
-
Last post by SnoBrdr
-
- 48 Replies
- 4007 Views
-
Last post by Goboy