Carb Sync Observations

Post your "How To", or share tips and tricks about maintenance related to four cylinder Wings. Only registered users can read this forum.

Moderators: Whiskerfish, Forum Moderators

Post Reply
User avatar
britman
Gold Member
Gold Member
Posts: 1202
Joined: Sun Jun 28, 2009 6:41 pm
Location: o fallon il
Contact:

Re: Carb Sync Observations

#16

Post by britman »

gapl1953 wrote:
BearOnt wrote:I bought myself a carb sync tool and put it to use today. :-D
I noticed a few things:
a) When you have one of the cylinders at exactly the right place it will move when you take the screwdriver off the adjusting screw. :shock:
b) Just because it was right a minute ago does not mean it will be right now. :-?
c) From idle to 3000rpm the difference is so great you wonder how it ever ran. :cry:
d) The warmer the engine gets the more frustrating this job gets. :evil: fly into a rage fly into a rage

I "think " I finally got it good. I would have to adjust it a bit high so it would be good when I removed my screwdriver. When I put the bike in 1st gear (bike on center stand) and reved it to 3000 rpm the levels in the sync tool seemed to calm down a fair bit and were easier to adjust. imsmilin

So the big question is: Shouldn't the bike be in gear under load to be able to accurately set the carbs? :?:


Reading this cause me to chuckle! I just came in from the garage after experiancing this same thing on a GL1000 I just put back together after a valve job. I even used two different gauge sets. I know these things are touchy but come on I spent three hours on something that takes me about 45 min on average. imsmilin
I just spent two hours i think none are in the same spot on the gauges . well one bike was but didnt mess with it as first time with gauges but 45 minutes come on
1983 gl1100 fully dressed the best colour black -- 1982 gl1100 going naked and black too 1983 Yamaha virago 700 also in black
User avatar
gapl1953
Zinc Member
Zinc Member
Posts: 49
Joined: Wed Mar 17, 2010 10:55 am
Location: springbrook wisconsin

Re: Carb Sync Observations

#17

Post by gapl1953 »

britman wrote:
gapl1953 wrote:
BearOnt wrote:I bought myself a carb sync tool and put it to use today. :-D
I noticed a few things:
a) When you have one of the cylinders at exactly the right place it will move when you take the screwdriver off the adjusting screw. :shock:
b) Just because it was right a minute ago does not mean it will be right now. :-?
c) From idle to 3000rpm the difference is so great you wonder how it ever ran. :cry:
d) The warmer the engine gets the more frustrating this job gets. :evil: fly into a rage fly into a rage

I "think " I finally got it good. I would have to adjust it a bit high so it would be good when I removed my screwdriver. When I put the bike in 1st gear (bike on center stand) and reved it to 3000 rpm the levels in the sync tool seemed to calm down a fair bit and were easier to adjust. imsmilin

So the big question is: Shouldn't the bike be in gear under load to be able to accurately set the carbs? :?:


Reading this cause me to chuckle! I just came in from the garage after experiencing this same thing on a GL1000 I just put back together after a valve job. I even used two different gauge sets. I know these things are touchy but come on I spent three hours on something that takes me about 45 min on average. imsmilin
I just spent two hours i think none are in the same spot on the gauges . well one bike was but didn't mess with it as first time with gauges but 45 minutes come on

Well I went back out in the morning and discovered I made a boo boo :oops: putting on the right belt. I corrected that and it took me 20 min and had them all sync-ed to the same number. I have done a good number of multi carb sync jobs which helps. You need to anticipate how much a turn of he screwdriver is going to affect the remaining carbs, whether there is one or eight additional carbs.
Current Stable; 1979 GL1000, 1973 CB500K1, 1973 CB750K3, 1985 CB700SC, 1984 BMW R80RT,
1996 Buell S-2 Thunderbolt

My father use to say, "Anyone can fix it with the right tools"!
I say, "If it don't fit, get a bigger hammer"!
User avatar
mortiki
Tin Member
Tin Member
Posts: 10
Joined: Tue Jul 27, 2010 5:58 pm
Location: warren, ar

Re: Carb Sync Observations

#18

Post by mortiki »

Here is another tip I hope helps someone. Best to use one gauge and record progress but if using multiple gauges pick one for base and record #3 then put #1 gauge on #3 and see what reading is. Record the difference and mark #1 gauge accordingly. Hook up #2 gauge to #3 and record difference and mark,again without any changes, and then #4 gauge on #3 and record difference and mark. Now all your gauges are calibrated to sync a lot closer. This method only works on the 4 gauge dial setup so if your using a single gauge or tubes it may not work.
There is never enough time to do it right but there is always enough time to do it over.
Edmond Burke,"The only thing neccessary for the advancement of evil is for good men to do nothing".

Current Stable:
2008 Roketa Bali 150(Scoobie)
2004 Honda CMX 250 Rebel(Johnny)
1983 Honda GL 1100i Goldwing(Bella)
1983 Honda GL 1100i Goldwing w/Voyager kit(Trixie)
1981 Honda GL 500 Silverwing(Silver)
1980 Suzuki GN 400(skat)
1979 Honda CX 500 Custom(Streak)
User avatar
Sandy
Gold Member
Gold Member
Posts: 1012
Joined: Tue Jun 17, 2008 9:15 am
Location: Barrie, ON, Canada
Contact:

Re: Carb Sync Observations

#19

Post by Sandy »

I calibrate each vacuum gauge to one common cylinder before hooking up the gauges to the individual cylinders.
Your vacuum gauges should have a little adjustment screw on the face of the gauge that will reposition the gauge face under the needle. just unscrew the gauge face plate.
I have also made a little 4 gauge header out of aquarium 'T's" and "90's" so all 4 gauges can be adjusted to one vacuum source.
Seems to work ok.

Image
-----------------
Sandy
1971 Honda CB350
1974 Honda XL350
1975 Red GL1000 (gone from stable but still in the family)
1976 (original owner in 76) Sulpher Yellow GL1000
1977 Restored then Triked Sulpher Yellow GL1000
1976 (garage find completed 2015) Sulpher Yellow GL1000
1978 Watsonian Monaco
1960 IH B414
http://www.flickr.com/photos/76_gl1000_project
bluewing
Lead Member
Lead Member
Posts: 6
Joined: Mon Aug 05, 2013 10:35 am
Location: Ontario, Canada

Re: Carb Sync Observations

#20

Post by bluewing »

I had a motion pro with the blue liquid but I had problems with air bubbles and loosing the liquid, also having to calibrate it every time I used it.
I ended up with a Morgan Carbtune and I find it to work very well, every time. It has metal bars that show the vacuum level instead of liquid or mercury and there is very little pulsing, it stays very steady.
Here is there website.
http://www.carbtune.com/
Ride safe, have fun and enjoy.
Lane.
bartmead
Brass Member
Brass Member
Posts: 20
Joined: Tue Jul 24, 2012 8:27 pm
Location: Adel, Iowa

Re: Carb Sync Observations

#21

Post by bartmead »

I too recently synched after a carb rebuild. I have the dial gauges and it took about 45 minutes to get it "close". If there had been a camera on me I would love to watch myself at super fast playback. I must have gone around the bike 500 times. I had my shop door open but I bet an air quality test by osha or the epa would have shown the air pretty deadly. I survived and only lost a few IQ points. My IQ is still high enough to use the internet.(thats not saying much)
77 GL1000
Atticka
Cast Iron Member
Cast Iron Member
Posts: 86
Joined: Mon Oct 21, 2013 5:21 pm
Location: Montreal

Re: Carb Sync Observations

#22

Post by Atticka »

Some of the newer model carb sync tools have a restriction in the hose to stop the needle from bouncing around so much, others have a valve that you can use to control the bounce of the needed.

I use a Morgan CarbTune.

On the GL1100 Cylinder #3 is the reference carb and has no adjustment screw, all other carbs will be synced to this one.

The #4 carb actually controls the entire left side, so adjusting #4 will move #2 along with it.

So...
Adjust #1 to #3
Adjust #2 to #4
Then Adjust #4 to #3 (which will bring along #2 with it).

Hopefuly this helps!
82 Honda GL1100 Interstate - project bike
82 Yamaha XJ550
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: Carb Sync Observations

#23

Post by gregforesi »

A true guru can sync these bikes with nothing but a screwdriver and an ear to the primary chain. When it quits rattling you've nailed it.
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
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carb Sync Observations

#24

Post by ericheath »

I read of a guy who holds a piece of tubing from each of two carbs in each ear. He said he could tell the difference in pitch from each ear. Now that's tuning.
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
User avatar
sunnbobb
Facebook Admin
Facebook Admin
Posts: 21272
Joined: Thu Jan 10, 2008 4:09 pm
My Album: http://www.ngwclub.com/gallery/v/wingmans/sunnbobb/
Location: LaConner, WA

Re: Carb Sync Observations

#25

Post by sunnbobb »

A true guru can sync these bikes with nothing but a screwdriver and an ear to the primary chain.
I watch the ears on my cat, when they quit twitching, she is in perfect synch. :)
I found the end of the internet

---- Bradshaw Bikes custom polishing for your wing. Visit us on facebook!

1978 Learning Experience
1980 County Road Hauler "Brain Damage"
1978 Cafe Custom Gl1000 "Vyper"
1977 Bulldog Inspired "Vaincre"
1981 Street Fighter GL1100 "No Quarter"
1983 Supercharged Street Drag "Anubis" (in worx)
1983 gl1100 mint restoration "Kristen"
1985 Aspencade..pondering.
User avatar
AussieGold
Silver Member
Silver Member
Posts: 838
Joined: Mon Jun 13, 2011 10:35 pm
Location: Australia

Re: Carb Sync Observations

#26

Post by AussieGold »

sunnbobb wrote:
A true guru can sync these bikes with nothing but a screwdriver and an ear to the primary chain.
I watch the ears on my cat, when they quit twitching, she is in perfect synch. :)
i also like to keep the cat in perfect synch........ lolol
Mentor to all self appointed (and genuine) GURUS.

An LTD is........it just is.
User avatar
fish
SUPER BIKER!!!!
SUPER BIKER!!!!
Posts: 3110
Joined: Wed Feb 18, 2009 1:50 pm
Location: tucson

Re: Carb Sync Observations

#27

Post by fish »

The Vincent spends so little time at idle I did the bench idle synch and let it go at that.
I also idle him at 1100 RPM it is smoother with a fast idle.
Timothy Mark Fisher
Catalina Arizona
"ride it.. don't be one of those guys who will fix it 'til it's broken" (JDVorchek)
"It is not logic or economics that drive a motorcyclist but passion!" (bugdaddy66)
"I fully agree with fish, well at least 27% of the time."(Casper)
"Why do you have to ruin a perfectly good thread with common sense"(Placerville)
"my best guess for an answer would be a stream of complex expletives" (Transitman)
"I like a cold beer with my beer" (OldeWing)
"Most of us like the sport of wrenching too." (fred camper)
"Now go ride the heck out of it, til mother says do your chores"(Gowing)
"I agree with Fish" (Salukispeed)
Paul Narramore
Titanium Member
Titanium Member
Posts: 367
Joined: Wed Dec 17, 2014 6:18 am
Location: Aylesford, Kent, UK

Re: Carb Sync Observations

#28

Post by Paul Narramore »

I pleased to read others also have problems with carb synchronising. A friend loaned me a set of four gauges, each with a small valve beneath each gauges which I presumed was an anti-flutter valve. They aren't. What seems to happen is that I turn an adjusting screw at which point, the needle stays still, then a tweek of the valve and the needle moves to a new reading. So each adjust has to be followed by a repeated tweeking of these valves.

I have carb 2 and 4 to match No3 (A reading of 4 on the gauges).

No1 though is a pain. No amount of turning of adjusting screw makes a bit of difference and the needle fails to move up or down (A reading of 1.5 on the gauge). Also the revs go sky high every now and again yet pressing down on the screw or it's back plate calms the revs.

In theory I'd like to detach all of the throttle cables from the carbs then the tightness or whatever wouldn't effect the carbs, then once the carbs are adjusted, re-attach the throttle cables.

So far, with three of the carbs reading the same, the bike is misfiring, popping and banging. Rubber tube no2 has an inch or two missing from the end where it goes onto the brass tube, and the popping and banging ejects this again and again.
Present bikes -

BMW R100/7
1989 BMW R100GS-Paris Dakar
MZ ETZ250 Trials
1977 Honda GL1000 GoldWing
User avatar
gltriker
Honored Life Member
Honored Life Member
Posts: 5053
Joined: Fri Sep 24, 2010 9:11 pm
Location: central NY State

Re: Carb Sync Observations

#29

Post by gltriker »

Paul Narramore wrote:I pleased to read others also have problems with carb synchronising. A friend loaned me a set of four gauges, each with a small valve beneath each gauges which I presumed was an anti-flutter valve. They aren't. What seems to happen is that I turn an adjusting screw at which point, the needle stays still, then a tweek of the valve and the needle moves to a new reading. So each adjust has to be followed by a repeated tweeking of these valves.

I have carb 2 and 4 to match No3 (A reading of 4 on the gauges).

No1 though is a pain. No amount of turning of adjusting screw makes a bit of difference and the needle fails to move up or down (A reading of 1.5 on the gauge).
Also the revs go sky high every now and again yet pressing down on the screw or it's back plate calms the revs.

In theory I'd like to detach all of the throttle cables from the carbs then the tightness or whatever wouldn't effect the carbs, then once the carbs are adjusted, re-attach the throttle cables.

So far, with three of the carbs reading the same, the bike is misfiring, popping and banging. Rubber tube no2 has an inch or two missing from the end where it goes onto the brass tube, and the popping and banging ejects this again and again.
What's the probability that the oring that seals the #1 carburetor's manifold, to the intake port on the cylinder head, is sufficiently damaged causing an air leak great enough to cause its specific vacuum gauge to be unresponsive to synchronizer screw adjustments?

edit: I reread the complaint again and noted you are tweeking the small valve beneath the gauges quite a lot. A reading of 1.5 never changes on #1. Have you tried switching two adjacent gauges' hookups and observe if that complaint follows the switch?
Maybe the tip of the needle in the small valve is stuck or broken off.
I noted on my 4 vacuum gauge set that if I shut a needle valve completely while the engine is idling, its specific gauge will hold that vacuum reading until the needle valve is opened again.
Last edited by gltriker on Tue Mar 22, 2016 8:54 am, edited 2 times in total.
Cliff (74yrs ;) )

Keep your eyes and ears open and you'll learn something new, everyday. tumb2

New users please visit our "Shop Talk" for common tips and help: <---jdvorchak
http://www.ngwclub.com/forum/page/ST
^^^^^^^click up here^^^^^ :oldies

RE: a thorough fuel tank cleaning
"And your carbs will thank you. They no longer live down stream from a sewage plant." -gregforesi tumb2
"Can't see the paint when your looking thru the handlebars..........." -Oldewing ;)
"I'd rather Ride than Shine" -RAT tumb2 Me Too!!

Cliff

'75 GL1000 home built trike; http://www.ngwclub.com/forum/viewtopic.php?f=30&t=39996
October,2017 BOTM :shock: 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.
User avatar
ericheath
Honored Life Member
Honored Life Member
Posts: 9580
Joined: Wed Jul 29, 2009 11:20 am
Location: Winnipeg, Manituba

Re: Carb Sync Observations

#30

Post by ericheath »

If number three is open too far to begin with you'll chase your tail all day. Everything is ultimately set to match #3's vacuum. It cannot be adjusted. If it's high, you'll adjust #1 too high. Then you'll do 2 to 4 and they may be correct, but when you sync 1-3 to 2-4 they'll all be too high. Pull the elbows and bench synch them as close to shut as you can, then warm it up and sync it. You may have to turn the idle set screw in to warm it up.
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
Post Reply
  • Similar Topics
    Replies
    Views
    Last post

Return to “How To 4-Wings (Tutorials Only)”