Carburetors

Discuss everything about Honda GoldWing. Feel free to ask any question related to GoldWing.

Moderators: CYBORG, Oldewing, robin1731, Forum Moderators

Post Reply
User avatar
pidjones
SUPER BIKER!!!!
SUPER BIKER!!!!
Posts: 3237
Joined: Wed May 22, 2013 4:06 pm
Location: East TN

Re: Carburetors

#16

Post by pidjones »

There is a kit available (Randakks had it) to fix the float pivot post. Unless you use one of the major rebuilders (all here on NGW) or do it yourself, expect problems. I've heard of way too many Honda shops and small shops botching carb rebuilds. Done yourself with care and attention to detail, they will only need redone two more times (at least, that's what it took me my first set).
"Love 'em all.... let God sort 'em out!"
Ex 2006 GL1800 - the Black Pearl SOLD! to make room for:
2021 Can-Am Spyder RT Limited Dark Chalk Metallic
1975 Red GL1000 project - ex Pistol Pete project
1972 Triumph T150V Trident rescue - finished and FOR SALE!
1976 Yamaha RD400c
1978 GL1000 with '75 engine - the Hunley
Ex 1978 GL1000
Ex 1979 GL1000
Ex '79 CB750F rat bike
Ex '86 SEi
Ex '77 GL1000
Ex '76 RD400
Ex '72 Penton 125 set up for flat track
Ex '73 RD250
Ex '68 TR6C - chopped
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: Carburetors

#17

Post by redglbx »

The 1100 carbs are indeed smaller and they use 4 of the 1100 specific anti-backfire diaphragms which are fairly expensive usually around $25 each. My experience with the 1100 carbs has been that they reduce the performance on a 1000 across the board and my experience has been that they generally will not rev more than about 6500rpm. But this is easily fixed by reducing the main jets from 145’s to 140’s and then they seem to rev fine to the 1000’s 8500rpm redline.

Now let me add that with smaller bores and the accelerator pump they SHOULD have better low end and better drivability. But again a well & PROPERLY setup set of 1000 carbs will outperform a set of 1100 carbs in my experience. But those that know me will tell you that I run 1100 carbs on my 76 but as I said earlier I have modified the hell out of them with a lot of machining time in them to improve the airflow through them. If you can match the same airflow of a bigger opening with equal or better airflow through a smaller opening you increase the airflow velocity which is better all around and will better atomize the fuel in the airflow and that increased velocity will improve the vacuum signal across the board with sharper throttle response as well.

Jetting, jetting is just a function of matching fuel metered into airflow to get you an acceptable fuel to airflow ratio, the ideal ratio is called “stoichmetric” and is 14.7 parts air to 1 part fuel, but that leaves little room to prevent any lean induced damaging knock. So the accepted thing is to run the air to fuel ratio (a/f) richer to prevent that. Honda did a couple of things here, they ran the a/f ratio very lean at the low end with the 35 idle jets and the 62 main jets which in my experience Gives you a 15-15.5/1 ratio which is very lean, this is done for emissions testing which is usually done up to around 2500rpm and is a self certified deal done by the manufacturers. They compensate that super lean condition then with super rich 120 secondary main jets that I’ve seen generally run in the 10parts air to 1 part fuel which is just pig rich and begins when the slides start to lift the needles out of the jets.

This is done to avoid warranty claims caused by the super lean condition damages in the lower jetting and to also help with the often complained about cold bloodiness, but again if you properly setup your super cleaned carbs this is all minimized. 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
User avatar
Rat
Photo Gallery Admin
Photo Gallery Admin
Posts: 15457
Joined: Fri Oct 21, 2005 9:59 pm
My Album: https://www.ngwclub.com/gallery/v/wingmans/rat/
RIP: cookie
Location: Toronto .... Canada

Re: Carburetors

#18

Post by Rat »

At least a nickel's worth I'd say …

Gord anim-cheers1
"I'd rather Ride than Shine"
‘14 KLR650 ... not a rat ... yet
‘84 GL1200i ‘R2B6' (Rat to Be 6, the last, adopted by twowings)
My Original 'RAT' was a hybrid '82 CB900/1100F
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: Carburetors

#19

Post by redglbx »

Rat wrote: Tue Mar 29, 2022 10:19 am At least a nickel's worth I'd say …

Gord anim-cheers1
😁😁😁😁🤔🤔🤔
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
BurnsYoFace34
Chrome Member
Chrome Member
Posts: 163
Joined: Sun Mar 06, 2022 10:19 pm
Location: Akron, Ohio

Re: Carburetors

#20

Post by BurnsYoFace34 »

Ok so how do you do a bench sync to get the carbs close im a little poorish cant afford to get the sync tool or the vaccuum test also anyone know what else I can use off the 81 on my 77 I see the 81 has air shocks in the rear
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: Carburetors

#21

Post by redglbx »

Burns, sorry to say but there is no way to sync your carbs well on the bench. If you use a drill bit or gage pin to get the throttle blades in the neighborhood but actually using vacuum gauges to sync your carbs compensates for differences in valve adjustments, compression differences cylinder to cylinder as well as differences in port diameters and textures as well as probably many other things that I’m not remembering right now. The only way to do this right requires vacuum gauges to adjust the carbs to compensate individually.

Watch eBay for a used set or check with friends who might be willing to help, join a local bike group and maybe someone can help. Sorry but there’s just no way to do this off the bike properly, as I said earlier if you set the throttle blades to be the same on the bench you may get lucky and have it good enough. Sorry but that’s the way it is. Where are you located ? Adding that and your bike info to your profile may help identify where you’re at along with maybe somebody close & willing to help.
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
User avatar
gregforesi
Honored Life Member
Honored Life Member
Posts: 4965
Joined: Wed Jun 10, 2009 8:42 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/Greg+Foresi/
Location: Venice, FL

Re: Carburetors

#22

Post by gregforesi »

redglbx wrote: Fri Mar 25, 2022 8:01 am The Weber setup has better low end punch but no top end. Probably due to the accelerator pump.
Really. The extra 11-12hp that my dyno run showed is useless?
2006 GL1800 (Brutus Maximus)
1978 GL1000 (White Trash - 2012 BOTY
(If you want to discuss the Trashmobile, Webers, Rearsets, Clubmans, or other stuff then send me a PM.)
"Getting old ain't for sissies" - Phyllis Diller
"So how much you gonna spend to win that $5 trophy?" - Cyborg
User avatar
dontwantapickle
Silver Member
Silver Member
Posts: 947
Joined: Fri Oct 13, 2017 9:26 pm
Location: Colorado

Re: Carburetors

#23

Post by dontwantapickle »

I'd really like to know more about the dyno results.
User avatar
Whiskerfish
President
President
Posts: 36853
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: Carburetors

#24

Post by Whiskerfish »

"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carburetors

#25

Post by ericheath »

Burns, a 0.004” feeler gauge is a good place to start a bench sync. You may have to loosen the other three to get the base carb to just touch the gauge. Try to get the other three the same. Then when you increase the throttle stop screw, all move together. You don’t want to slide it more than enough to feel it’s snug-ish. It doesn’t take much to leave a mark in the throttle plate’s edge.

I can get them pretty close by closing the throttle plate down on the three holes in the bore. I try and cover half of the hole.

The syncing order is different on some bikes. One side has only one adjuster. The one on these side is the base carb. It can’t be adjusted except by the throttle plate. Match the one next to it with the base carb. Then go to the other side and match the two carbs using the middle adjuster. Last is matching one side to the other side with the last adjuster which is rearward of the back carb.
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
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: Carburetors

#26

Post by redglbx »

Greg, I would love to see your torque dyno curve ! The Wings that I’ve ridden with Weber’s have all been the single carb version which imho give a great low end punch but really suffer at the upper rpm. But they also tend to be much smoother running (no sync issues). 11-12hp is a significant increase, don’t know if that was just tongue-in-cheek but Randakks dual Weber setup does seem to work.

Also, don’t know if you’re looking for more but milling the heads .040in (you an go up to .050in) and optimizing the cam phasing and I believe you would be in the 90hp at the rear wheel range. I find the fuel curve interesting as well, it has that “glut” where it goes really rich that I think is from the accelerator pump hit and then your Weber’s get fairly lean where the oe carbs go really rich to around 10-1a/f , 10.5-1 a/f . Very interesting ! Thanks ! These old girls can make some horses, not compared to the current stuff but respectable !

Just looked at the date and see that it was 10yrs ago,,still cool !
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
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carburetors

#27

Post by ericheath »

redglbx

You should have a look at these. https://ngwclub.com/forum/viewtopic.php ... ers+around
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
BurnsYoFace34
Chrome Member
Chrome Member
Posts: 163
Joined: Sun Mar 06, 2022 10:19 pm
Location: Akron, Ohio

Re: Carburetors

#28

Post by BurnsYoFace34 »

I kinda assume I have a vaccuum leak somehere during cold start the bike idles roughly 1100 rpms but once it gets a little bit of heat in the bike the rpms jump up to anywhere from 3k to 6k rpms
redglbx
Gold Member
Gold Member
Posts: 1116
Joined: Tue Jun 02, 2020 8:39 am
Location: NW Indiana,

Re: Carburetors

#29

Post by redglbx »

Burns, a couple of thoughts & questions. Does your bike have one of the vacuum petcocks ? Does the rough idle occur when it’s warmed up after being run or only when cold started. Does it do this when run frequently or only after sitting for a length of time.

The reason I ask is that this sounds a lot like normal Honda starting when it’s sat for a length of time or has one of their vacuum petcocks and is the result of low or no fuel in the carbs & improves once the carb’s are filled. If it happens all the time then I would suggest you check that the fuel filter is not restricting flow or maybe a sluggish fuel pump. The service manual recommends a flow test in it but I don’t have that in front of me currently. What year is your bike ?

To check for a vacuum leak it can only be a few things, the joints of the intakes or around the throttle shafts on the carbs. I use a can of wd40 with the straw to spray around each joint with the motor runnng and if the idle picks up then you’ve found your leak.
Last edited by redglbx on Mon Apr 04, 2022 7:11 am, edited 1 time in total.
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
User avatar
Whiskerfish
President
President
Posts: 36853
Joined: Thu Feb 16, 2006 9:34 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/whiskerfish/
Location: Norfolk Va

Re: Carburetors

#30

Post by Whiskerfish »

Could be a vacuum leak for sure. Also check for the required free play of the throttle cable. If it does not have the recommended slack it will do this.
"Agreement is not a requirement for Respect" CDR Michael Smith USN (Ret) 2017
"The book is wrong, this whole Conclusion is Fallacious" River Tam
2008 GL1800 IIIA "TH3DOG"
1975/6/7/8/9 Arthur Fulmer Dressed Road bike
1975 Naked Noisy and Nasty in town bike
and a whole garage full of possibilities!!

Psst. oh and by the way CHANGE YOUR BELTS!!!!
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “GoldWing Tech Discussions”