Topic: carb synchronizer how to

[Duanob]

Since we're getting into the actual "how-to" of carb tuning I saw this posted on another thread from Youtube. I thought it was pretty informative.

I'll be watching it when the time comes.

[TwoTired]

I've seen the video before.

Mistakes made were syncing with the RPM way too high.  It should be at idle or about 1000 RPM for the Cb550.  This is where the adjustment is most sensitive.

With these particular carbs, you pick the carb with the highest vacuum, declare it the "master" and never adjust the slide on that one.  You adjust the other three to the reading the "master" carb has.
Reason being, is that it is possible to skew all the slides adjusters so that idle speeds can't be achieved by the idle knob (likely what was wrong with the bike in the video).

[Duanob]

Thanks for the heads up TT.

[Coyote13]

Thanks for the heads up TT.

X2 very informative, as always

Thanks for posting that vid also, I'm about to have to sync my carbs, that's gonna come in handy

[Mavryk03]

I've seen the video before.

Mistakes made were syncing with the RPM way too high.  It should be at idle or about 1000 RPM for the Cb550.  This is where the adjustment is most sensitive.

With these particular carbs, you pick the carb with the highest vacuum, declare it the "master" and never adjust the slide on that one.  You adjust the other three to the reading the "master" carb has.
Reason being, is that it is possible to skew all the slides adjusters so that idle speeds can't be achieved by the idle knob (likely what was wrong with the bike in the video).

that was the vidoe i was going to use as well when the time came, TT you should make us video and put up here b/c you are the wise one with all the knowledge and know how 

[Mavryk03]

on the slides do you have to loosen the nut, before adjusting the screw?

[flybox1]

on the slides do you have to loosen the nut, before adjusting the screw?

YES.   

http://www.bikebandit.com/motion-pro-carburetor-adjustment-tool

[Mavryk03]

there is always something

[Mavryk03]

so you cant just use a wrench to loosen the nut then adjust the screw?

[maxspeed140]

+1 referencing Deltarider's advice. Syncing my carbs was the last thing I did. The bike was very rideable I believe because I had done the other things first. When I did sync them, it was using a Morgan Carb tune. That's when I found that my #3 carb was almost off the scale. Now it runs even better.

[OrganDonor]

I've seen the video before.

Mistakes made were syncing with the RPM way too high.  It should be at idle or about 1000 RPM for the Cb550.  This is where the adjustment is most sensitive.

With these particular carbs, you pick the carb with the highest vacuum, declare it the "master" and never adjust the slide on that one.  You adjust the other three to the reading the "master" carb has.
Reason being, is that it is possible to skew all the slides adjusters so that idle speeds can't be achieved by the idle knob (likely what was wrong with the bike in the video).

Not sure I'm understanding this properly.  My carb #2 has no adjustment screw, therefore I adjust the other 3 carbs to be in sync with this one.  Is this incorrect?  I've got a 77 550K.

[Deltarider]

Not sure I'm understanding this properly.  My carb #2 has no adjustment screw, therefore I adjust the other 3 carbs to be in sync with this one.  Is this incorrect?  I've got a 77 550K.

Yep.

[TwoTired]

Not sure I'm understanding this properly.  My carb #2 has no adjustment screw, therefore I adjust the other 3 carbs to be in sync with this one.  Is this incorrect?  I've got a 77 550K.

The PD carbs have the master carb designated by Honda.  It is #2.  There is little option but to adjust the other carbs to #2's vacuum level.

Cheers,

[OrganDonor]

OK - that's what I thought.  Thanks.

[lucky]

so you cant just use a wrench to loosen the nut then adjust the screw?

Yes you can BUT...You must adjust #2 carb FIRST!!!
All the other carbs are adjusted in relation to the #2 carb/ Also the pilot airscrew and idle adjustment must already have been performed.

I feel that if you just adjust all of the slides position the same as #2 with a vernier caliper that you will be within .001 of having all the slides the same.
If there are still problems you will need to replace your throttle linkage shafts
where the throttle linkage goes through the body of the carb.

So basically you are using a vernier caliper to get the slides all in position instead of a vacuum gauge.

I used this method and got BETTER results using the vernier caliper to measure from the top edge of the slide to the top edge of the carb body.

[lucky]

+1 referencing Deltarider's advice. Syncing my carbs was the last thing I did. The bike was very rideable I believe because I had done the other things first. When I did sync them, it was using a Morgan Carb tune. That's when I found that my #3 carb was almost off the scale. Now it runs even better.

The carb sync is the very last thing like the icing on the cake.

[bollingball]

 Quote from Lucky
Yes you can BUT...You must adjust #2 carb FIRST!!!
What carbs are you talking about?
Ken

[Duanob]

so you cant just use a wrench to loosen the nut then adjust the screw?

Yes you can BUT...You must adjust #2 carb FIRST!!!
All the other carbs are adjusted in relation to the #2 carb/ Also the pilot airscrew and idle adjustment must already have been performed.

The OP's carbs, not necessarily. the 022A and 087 don't have a master carb.

[Faster]

First , the information given for the cylinders it's incorrect . The far right it's numb 4 and not numb 1 . There is not such rule that they need to be tuned in pairs and that depends how close they are at the time . Another thing , this is not meant to be done on high revs but on idle ( 1k to 1.1k ) . Engine should be already  warm / hot in order to do an accurate reading .

[rotortiller]

Basically this is what you should end up with.

[Faster]

Well done

[Greyhound]

In a perfect world, better to use carb sync which has a single gauge, along with a breather valve.

This way you get a more accurate reading since all of the carbs get synced from the same gauge VS four different gauges which have the possibility of being calibrated slightly differently. Also, the breather valve will allow just a little pressure out, resulting in the needle not jumping around so much with the each stroke, allowing for a much more accurate reading as well.

I made my own like this years ago, just get a single vacuum gauge from online, then the hoses and valves from HomeDepot (or order them online too)... total kit like $25.

Common Motor also recently started selling one exactly like this ($90), which is way overpriced in my opinion, but works much, much better than the four-gauge syncs for the aforementioned reasons.

[scunny]

Good luck trying to use just one. On the 4 gauge set up, you calibrate all 4 gauges on the same cylinder, then, perform the synch.

[Deltarider]

On the 4 gauge set up, you calibrate all 4 gauges on the same cylinder..

But... not simultaneously!

[PeWe]

Skip the vacuum tools.
Bench sync work good enough.

Done that with good result on stock CB750 K6 carbs and Mikuni VM29 smoothbores that have no vacuum connections. Kawasaki has that on the carb boots when using these.

I purchased Morgan carb tune to synch my Mikuni flatslides a few years ago.

Setting the ignition correct will make big difference. If points, use a dwell meter and set both equally.