Motorcycle Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
I have a 1978 CB750A Hondamatic, I just recently rebuilt the carbs and put them on the the bike and pretty much put the carbs back to the suggested factory settings. The bike fired right up with no issues (just a little tweak here and there) and now I would like to sync them. Can anyone suggest the best method to use, either the single guage that is placed on each carb inlet or a regular 4 guage set? I didn't think of it at the time when the carbs were off, and I was trying to look the other day I did not see any ports to connect any vaccum hoses. Any help or info will be greatly appreciated..............
 

Attachments

·
Angel's Realm Where Evil Fears To Tread
Joined
·
1,994 Posts
4 gages all at the same time is easier to do the job.
You can see all levels and adjust on the fly.
If you only use a single gage and move it to the other carbs you will have a harder time getting them the same.
on the 650 the #2 carb is not adjustable it is the one you use to set the other carbs with. If this is the same on your bike you would have to check the # 2 carb then remove the gage and put on a different carb while the bike stayed at the same speed
with 4 gages even if the bike speeds up you can still see the new setting by compairing it to the #2 carb
again this is only if the # 2 carb is your adjustment carb on that bike I don't know for sure.
I hope this helps.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #3 ·
Thanks for the reply, your info is very detailed and makes alot of sense, I will order the guage set today, and we will see how it goes.........
 

·
Registered
Joined
·
220 Posts
If your carbs don't have a vacuum port for connecting the 4 gauge model then you will have to try the one you have pictured and measure one at a time.
 

·
Angel's Realm Where Evil Fears To Tread
Joined
·
1,994 Posts
I have a pic of my carbs and you can see the screws on the side I marked it
I don't know about your carbs but you should be able to find a pic online of the carb vacuum port holes. Look on your carbs for something like the pic
 

Attachments

·
Registered
Joined
·
17 Posts
Discussion Starter · #6 ·
Thanks Kev, I have to look for the ports, if they are there. I was reading another thread about carb syncing a while ago and lost it, but from my understanding they should be small screws that get removed on each carb inlet on the engine side of the carbs is this correct?
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #7 ·
Archangel, you couldn't be anymore on the mark, you answered my post to Kevhead. Thanks to you both it should go pretty smooth, I will keep you both posted........
 

·
Registered
Joined
·
29 Posts
I would recommend taking one of those screws out and measuring the diameter and the thread pitch (peak to peak) before ordering a kit. You want to make sure the kit you are buying has the right size vacuum fittings.

Yours may be the "standard" (which seems to be 5mm) but my 360 had a 6mm fitting and most kits don't come with those. Better safe than sorry!
 
1 - 10 of 10 Posts
Top