Needing One of my Carbs Sync.

[dan7uk]

Had a vacuum leak on #5 carb, fixed the leak now I need to sync #5 to #3.  Don't want to buy a gauge for a one time check, I'm too cheap.  I did run the sync screw in on #1  counting the turns until it lightly seeded, matched turns in to #5 to get in the ballpark but I would feel better if it was sync.  I live in Louisville Ky anyone have a sync gauge that I could use, ride to you and so I could check my sync on #5?

[WintrSol]

Bit of a ride from Louisville to St.Louis, but if no one closer responds, I have a DigiSync, and will help out.

[dan7uk]

Thanks for the offer, a bit too far.  I may have to break down and buy a Digi Sync.

[Pluggy]

DigiSync Is is a great invention. It is also expensive. Too expensive for me, as I use such a tool about once every three years. 

There are other ways to measure and adjust vacuum that are satisfactory and less expensive. There is a DIY carb sync tool that is shown in SHOP TALK.  And, the Honda shop manual describes how to sync the carbs with a vacuum gage set like this one.

https://www.amazon.com/Alltooetools-Carburetor-Synchronization-Synchronizer-Adjustment/dp/B0C88SJCJ9/ref=sr_1_6?crid=24ACBRVD8GCZ6&dib=eyJ2IjoiMSJ9.ph_CZa7Mc9GwU_JyX29l7j96KM5luAwM5m8jd_E5lYZPS3nDo5U2CsCENgA7wMd1f5DIDeUd2f5YRC04YPPvFDBV86XxOvD8WWRmH8MuiohZQw16sgp83iOO0QkxSO8oqha7Mtac0ocXKR-kTNBKWIYmVuGpvVJ02uiecmp20agwg9am-KjRA-ghQ9ItJzcmWwPKy7nAp1IlN2IZ6NaV63vRh6ZVS2D6IBZg5FjbTc6TNgoNMNCpLHd7pX0piScmKAl6qArIkyKbarepuyxef0Jr-tsecUkmIT4y9akze58.cPo7rq3o_VYn5ABuKO4fqJIlc9215Ue25OgwLiimHtc&dib_tag=se&keywords=motorcycle%2Bcarburetor%2Bsynchronizer&qid=1755429822&sprefix=motorcycle%2Bcarb%2Caps%2C204&sr=8-6&th=1

[98valk]

Thanks for the offer, a bit too far.  I may have to break down and buy a Digi Sync.

I have two sets of vacuum gauges I can sell you.  one set I never used. the other set used on my '81 cb900 one time.

[WintrSol]

The main benefit of the DigiSync is you can verify the other carbs are as close as you thing they are. The downside is you rarely use it for the $$$ one costs. I'm one of those guys who says 'he who has the most tools wins'; I also offer to help others sync their bikes, so it does get use more often.

An, yes, too hot to ride from Louisville, unless you like long trips after sundown.

[Jims99]

The screw on the bottom of the carb that you lightly seat and count turns is air fuel mixture. The screws to sync carbs are up on the linkage. Not sure what screw you were referring to, just my thoughts.

[Mooskee]

If you feel like coming to Southport NC, I will balance the other 5 carbs to #3, (the screws on the side with the springs}, and tune the bike for proper combustion ratio, (the pilot screws on the bottom).

They interact such that when you adjust 1 it changes other readings. We will probably need to adjust them all when doing it to get them within spec.

If you do it yourself, the best sequence is 1-5-4-2-6. That gets you into the ball park the fastest. Then you can home in on it with little tweaks. Snap the throttle to settle the springs and check the adjustments until they stay in adjustment. Once adjusted the will stay put for a long time.

I have Gunson Color tuners also. It is a spark plug with a window so you can see the combustion color. and tune for a proper ratio. It is a bit of snake oil and science. It can be used with other input like heat, exhaust smell, engine backfiring etc..

Here is a link to a video of me explaining the process.
https://www.youtube.com/watch?v=LrbXjakM-TI

I also have a spare Digi Sync that if you prefer I can arrange to loan you.

Just let me know if you need my help.

[dan7uk]

The screw on the bottom of the carb that you lightly seat and count turns is air fuel mixture. The screws to sync carbs are up on the linkage. Not sure what screw you were referring to, just my thoughts.

It was the sync screw

[dan7uk]

If you feel like coming to Southport NC, I will balance the other 5 carbs to #3, (the screws on the side with the springs}, and tune the bike for proper combustion ratio, (the pilot screws on the bottom).

They interact such that when you adjust 1 it changes other readings. We will probably need to adjust them all when doing it to get them within spec.

If you do it yourself, the best sequence is 1-5-4-2-6. That gets you into the ball park the fastest. Then you can home in on it with little tweaks. Snap the throttle to settle the springs and check the adjustments until they stay in adjustment. Once adjusted the will stay put for a long time.

I have Gunson Color tuners also. It is a spark plug with a window so you can see the combustion color. and tune for a proper ratio. It is a bit of snake oil and science. It can be used with other input like heat, exhaust smell, engine backfiring etc..

Here is a link to a video of me explaining the process.
https://www.youtube.com/watch?v=LrbXjakM-TI

I also have a spare Digi Sync that if you prefer I can arrange to loan you.

Just let me know if you need my help.

Thanks for the offer, I may just break down and buy a Digi sync.  Amazon has it listed for $205.95

[Mooskee]

$205.95 is a good price. It is a great tool.

[Joe333x]

If you feel like coming to Southport NC, I will balance the other 5 carbs to #3, (the screws on the side with the springs}, and tune the bike for proper combustion ratio, (the pilot screws on the bottom).

They interact such that when you adjust 1 it changes other readings. We will probably need to adjust them all when doing it to get them within spec.

If you do it yourself, the best sequence is 1-5-4-2-6. That gets you into the ball park the fastest. Then you can home in on it with little tweaks. Snap the throttle to settle the springs and check the adjustments until they stay in adjustment. Once adjusted the will stay put for a long time.

I have Gunson Color tuners also. It is a spark plug with a window so you can see the combustion color. and tune for a proper ratio. It is a bit of snake oil and science. It can be used with other input like heat, exhaust smell, engine backfiring etc..

Here is a link to a video of me explaining the process.
https://www.youtube.com/watch?v=LrbXjakM-TI

I also have a spare Digi Sync that if you prefer I can arrange to loan you.

Just let me know if you need my help.

Just curious why you said that the color tune is a bit of snake oil? I used one after I rebuilt my carbs since it seemed like the best possible way to dial it in

[Mooskee]

If you feel like coming to Southport NC, I will balance the other 5 carbs to #3, (the screws on the side with the springs}, and tune the bike for proper combustion ratio, (the pilot screws on the bottom).

They interact such that when you adjust 1 it changes other readings. We will probably need to adjust them all when doing it to get them within spec.

If you do it yourself, the best sequence is 1-5-4-2-6. That gets you into the ball park the fastest. Then you can home in on it with little tweaks. Snap the throttle to settle the springs and check the adjustments until they stay in adjustment. Once adjusted the will stay put for a long time.

I have Gunson Color tuners also. It is a spark plug with a window so you can see the combustion color. and tune for a proper ratio. It is a bit of snake oil and science. It can be used with other input like heat, exhaust smell, engine backfiring etc..

Here is a link to a video of me explaining the process.
https://www.youtube.com/watch?v=LrbXjakM-TI

I also have a spare Digi Sync that if you prefer I can arrange to loan you.

Just let me know if you need my help.

Just curious why you said that the color tune is a bit of snake oil? I used one after I rebuilt my carbs since it seemed like the best possible way to dial it in

Oh I rebuild about 25 sets of carbs per year and use the Gunson on each set when I tune them on my test engine. It is a great little tool. I only mean that one needs to interpret what is Bunson burner blue, and it is good to use other indications such as exhaust smell, and the heat coming off the engine, and whether there is any backfiring.

I think the ideal would be an exhaust gas analyzer, but our stock  exhaust is not suitable for that. The Gunson is great. Tuning is also a bit of an all around interpretive process to get it perfect.

That said, if you didn't have any means to tune and just set the pilots to the factory spec starting point, it would be close enough that most of us would never notice. I usually end up 1/8th to 1/2 turn from starting point, and some cylinders are good at the starting point.

How often have riders installed open exhaust like Cobra 6 into 6 and not retuned or rejected. The bike will run a bit lean, and a bit hotter, and lose some HP, but the engine is strong enough that they are happy with it.

I like the Gunson. I have 2 of them.

Dave

[WintrSol]

The Gunson is probably fine if you have a strong spark. Couldn't get my old CB450 to run well enough with it installed, so went with the other indications.

[dan7uk]

Thanks to all, I just bit the bullet and purchase a Digi Sync.