Carb syncronisation


Information and questions on GL1100 Goldwings (1980-1983)
  • Sponsored Links
User avatar
moffat
Posts: 264
Joined: Thu Aug 05, 2010 2:30 pm
Location: Northwich United Kingdom
Motorcycle: 1982 GL1100
Interstate

Carb syncronisation

Postby moffat » Sun Aug 19, 2012 3:54 pm



Carb Syncronisation. I have connected the 4 gauge test meters to my 1982 GL1100 and the vacuum differnce is within limits. Howewever what should the gauges read as only the differnce in the readings appears to be the issue??????



User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Carb syncronisation

Postby littlebeaver » Sun Aug 19, 2012 5:13 pm

That's a good question, I will write it down next time I check mine...I know that the three other carbs should be balanced off of the #3 carb, once they are all equal at idle [950 rpms] then be sure to throttle it up and watch the gauges as they raise up, the purpose is to make sure they all raised pretty equally, if one were to stop and the other three still raise then you know that that piston [slide] is hanging up or getting stuck...That's an easy way to see if they are all good and not hanging up..

User avatar
WingAdmin
Site Admin
Posts: 17050
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: Carb syncronisation

Postby WingAdmin » Tue Aug 21, 2012 10:56 am

It depends on the condition of the cylinders (rings), atmospheric pressure, altitude, calibration of your gauges...

It's more important that the numbers match, than what they numbers actually are.

User avatar
moffat
Posts: 264
Joined: Thu Aug 05, 2010 2:30 pm
Location: Northwich United Kingdom
Motorcycle: 1982 GL1100
Interstate

Re: Carb syncronisation

Postby moffat » Tue Aug 21, 2012 11:11 am

thanks admin. new bores and rings. roughly sea level. new fit for purpose gauge set gauges are reading in the ref zone which states faulty valve timingle and leaky inlet manifold which is not the case.readings are all about 150 mm mercury with very little difference at tick over.

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Wed Aug 22, 2012 5:41 pm

I'm having a similar issue with my 83 goldwing aspencade. Just refreshed the carbs, including new air cut valves. The left two cylinders are showing low vacuum where the gauge says "late valve timing, or leak at intake manifold or heat riser." could this be caused by a couple of stuck air valves? I already checked the timing belts to make sure the sprockets lined up with their marks.

Any ideas?

User avatar
virgilmobile
Posts: 7663
Joined: Sun Sep 19, 2010 5:39 pm
Location: Denham Springs,La.
Motorcycle: 1988 GL1500 I
Previously owned
78 GL1000
81 GL1100
82 GL1100 I
83 GL1100 I
83 GL1100 standard
84 GL 1200 I

Re: Carb syncronisation

Postby virgilmobile » Thu Aug 23, 2012 4:28 pm

Uneven idle vacuum is in the adjustments.
Like said above.I ignore what the vacuum gauge says.Remember,it was intended for full manifold vacuum testing on auto engines,not a single cylinder engine.(one per carb)
If you use mechanical gauges,buffer the needle bounce and adjust for equality for each one.
This is assuming all the gauges read the same to start with.
I tied all mine together to a single vacuum source first thing and found 5" vacuum reading differences.
As I recall,they showed around 10" of vacuum at a idle.
I subsequently dumped all of them in the trash and made my own test rig.http://www.goldwingdocs.com/forum/viewt ... 94&p=40711

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Thu Aug 23, 2012 5:09 pm

That's the thing, I can't adjust it so that the left cylinders match the right. It's a huge difference. I also swapped the gauges around and got the same results.

User avatar
scotterichmond
Posts: 613
Joined: Fri May 06, 2011 3:49 pm
Location: Marblemount,wa
Motorcycle: 1975 GL1000
[img]http://images.goldwingdocs.com/scotterichmond_32376/Modestly_restored_1975_GL1000_750/engine_repainted_even_new_embl_3919.jpg[/img]

Re: Carb syncronisation

Postby scotterichmond » Thu Aug 23, 2012 5:19 pm

are the cam belts set right?

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Thu Aug 23, 2012 5:44 pm

Yes, they are.
I'm going to double check for vacuum leaks I guess. Maybe the rubber seals that go around the carburetors are bad or not seated right.

User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Carb syncronisation

Postby littlebeaver » Thu Aug 23, 2012 8:33 pm

first thing I'd check would be the plug by the battery, check to make sure the ohms are correct there using a multimeter or ohm meter, one of the wires could be bad, the connection could also be bad there..It's the plug that comes from the pulse Generator yeh that one, If it checks out good then it's probably the spark wires or your spark caps, also check the coil for cracks...

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Thu Aug 23, 2012 8:45 pm

littlebeaver wrote:first thing I'd check would be the plug by the battery, check to make sure the ohms are correct there using a multimeter or ohm meter, one of the wires could be bad, the connection could also be bad there..It's the plug that comes from the pulse Generator yeh that one, If it checks out good then it's probably the spark wires or your spark caps, also check the coil for cracks...


What exactly does that have to do with syncing the carbs and vacuum readings?

User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Carb syncronisation

Postby littlebeaver » Thu Aug 23, 2012 8:59 pm

Timing ...You can set it to t-1 and check the belts all you want but if those marks are not correct at an idle then perhaps one of the ignition compontents is faulty..Wires' plugs, PG parts ect. and if that's the case your going play hell syncronizing the carbs proper..Best way to confirm your marks is using a timing light on the engine..If you have a bad coil two of the carbs could read different..Timing light will tell you..Is all I'm saying..

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Thu Aug 23, 2012 9:39 pm

littlebeaver wrote:Timing ...You can set it to t-1 and check the belts all you want but if those marks are not correct at an idle then perhaps one of the ignition compontents is faulty..Wires' plugs, PG parts ect. and if that's the case your going play hell syncronizing the carbs proper..Best way to confirm your marks is using a timing light on the engine..If you have a bad coil two of the carbs could read different..Timing light will tell you..Is all I'm saying..



I still don't understand how IGNITION timing could affect VACUUM and what that has to do with VALVE timing. I know how to put the engine at TDC and if the marks on the cam sprockets are lined up with the marks on the case then valve timing is correct. I just don't see how ignition issues could affect vacuum.

If there is some way then you would need to explain it in more detail for me to understand.
Are you saying to use a timing light on the cam sprockets rather than the crank?

User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Carb syncronisation

Postby littlebeaver » Thu Aug 23, 2012 10:39 pm

If it's not hitting on all four cylinders proper it has everything to do with the vacuum of that cylinder..

User avatar
moffat
Posts: 264
Joined: Thu Aug 05, 2010 2:30 pm
Location: Northwich United Kingdom
Motorcycle: 1982 GL1100
Interstate

Re: Carb syncronisation

Postby moffat » Fri Aug 24, 2012 1:59 am

Thanks for the interest chaps but my simple question was. "What should the gauges actually read when carrying out the sync test as the manual only mentions differnece betwen the readings".
I have realised that the four gauge set with variable restrictors I bought for the job is really for a car engine and not for a motorcycle with 4 carburettors so the readings in the red zone do not apply to Goldwings. My vacuums show little differnce between eac oither and all gauges where compared with a common vaccum feed before starting the tgest as its best not to trust even new equipment accuracy.
Lets forget the matter shall we???

User avatar
littlebeaver
Posts: 4420
Joined: Mon Sep 21, 2009 6:11 pm
Location: Kansas City, Kansas
Motorcycle: 1981 gl 1100 I , 79 Yamaha XS11
Special, 82 Kawa 750 CSR, 82 Kawa 750 LTD, 03 Kawa Nomad 1500, 99 Kawa Voyager 1200

Re: Carb syncronisation

Postby littlebeaver » Fri Aug 24, 2012 11:13 am

moffat wrote:Thanks for the interest chaps but my simple question was. "What should the gauges actually read when carrying out the sync test as the manual only mentions differnece betwen the readings".
I have realised that the four gauge set with variable restrictors I bought for the job is really for a car engine and not for a motorcycle with 4 carburettors so the readings in the red zone do not apply to Goldwings. My vacuums show little differnce between eac oither and all gauges where compared with a common vaccum feed before starting the tgest as its best not to trust even new equipment accuracy.
Lets forget the matter shall we???

Oh :shock: ....Sorry about that Moffat...We shall....

Tombrewster421
Posts: 20
Joined: Wed Aug 22, 2012 2:26 pm
Location: Roy, Washington
Motorcycle: 1983 GL1100A Aspencade

Re: Carb syncronisation

Postby Tombrewster421 » Fri Aug 24, 2012 10:41 pm

Looks like my issue must have been stuck rings. I tried soaking the cylinders with ATF and that cleared the problem. Thanks for the advise guys.




Return to “GL1100 Information & Questions”




Who is online

Users browsing this forum: No registered users and 1 guest