Carb sync procedure for Carbtune

[dannymax]

I know this is posted in several locations on the forum and....here's one more. :biglaugh:

I will refer to the carbs by their factory designation, following is the orientation

front

#2 #4

#1 #3

rear

The first photo is of the right side (sitting on the bike) of carbs #3 & #4 and shows 2 sync screws just above the mounting brace

The second photo is of the left side (sitting on the bike) of carbs #1 & #2 and shows only 1 sync screw which points downward towards the mounting brace

Be sure your bike is warmed up and shut off

Place the Carbtune in an upright position above the gauges where you can see it from both sides of the bike (hang it on a long wire from the ceiling if possible)

Remove the plastic intake manifold covers from both sides

Remove the vacuum advance hose from #2 carb sync spigot and the rubber caps from #1, #3 & #4 carb sync spigots

Attach the Carbtune hoses to sync spigots as follows....1st hose to #1 carb, 2nd hose to #2 carb and so on (makes it easier to keep track of which carb you're adjusting later on)

Start the bike and adjust idle to 1100 rpm

Adjusting the screws:

Screwing them in drops the Carbtune rod, backing them out raises the rod

The screw on the left side adjusts #1 carb only......(#2 carb is the master carb and has no sync screw, it is adjusted at the factory and the other carbs are sync'd to it)

The 2 screws on the right side work as follows:
-the rear screw adjusts #3 carb only
-the front screw adjusts #3 & #4 simultaneously

Procedure:

Start on the left side by adjusting #1 carb to #2 carb
Move to the right side and adjust #3 carb to #4 carb (using the rear screw)
Adjust #3 & #4 carbs to #1 & #2 (using the front screw)

Blip the throttle after each change

The above process will involve moving from one side to the other as changes to one carb can minutely affect other carbs

That's all there is to it....it probly sounds like a bunch of mumbo jumbo but becomes easy with a little practice.

 

[sdt354]

Thanks Dan-o. It's important to a good performing Vmax. For those setting their A/F screws by the ear method, this must be done right first for good response from the A/F screws.

 

[SpecOps13]

Great write up Dan-o

 

[dannymax]

Thanks Dave.

 

[Tex85]

Perfect write-up. To anyone who may hesitate, this is a super simple task to complete DIY (so easy, I can do it)!

 

[dannymax]

Thanks Tex.

 

[tugla]

Sweet discription dannymax....
Only thing I would add is
Make sure to remove the screwdriver from the screw to view sync as it does chg just the pressure applied to the screw....
I might have missed that in your discriptions ....just started my coffee

 

[dannymax]

Absolutely right Rov.....they are very, VERY sensitive screws....miniscule adjustments only! unk:

 

[Traumahawk]

Great write up Danny.

 

[dannymax]

Thanks Eric!

 

[tugla]

Absolutely right Rov.....they are very, VERY sensitive screws....miniscule adjustments only! unk:

I might have learned that one over a piece of pie and ice cream down in ny state somewhere ...unk:

 

[dannymax]

I might have learned that one over a piece of pie and ice cream down in ny state somewhere ...unk:

Ya know....I think that might just be the case! :biglaugh:

 

[Demonsinmysemen]

Thanks Dan-o. It's important to a good performing Vmax. For those setting their A/F screws by the ear method, this must be done right first for good response from the A/F screws.

Hey, dude. You've helped me out a lot in the past and I appreciate it it. Next step is the synchronisation of the carbs. I got a good deal from this post, although my base carb is basically reading zero unless I blip the throttle. I shot some carb cleaner on the boots and carb thinking there may be some sort of leak. No changes. Any recommendations?

 

[dannymax]

Are they sync'd?

 

[rolling18]

What numbers are you adjusting them too? whats the target #??

 

[Traumahawk]

What numbers are you adjusting them too? whats the target #??

Its not really a set number, its more of having them all at the same number/level.

 

[[email protected]]

Its not really a set number, its more of having them all at the same number/level.

Mine typically ends up around 25 cm Hg but as Eric noted, all the same is what matters not a specific numba'

 

[Cato Garcia]

i recently cleaned my carbs and it was idling weird. So i ordered me up a morgan carbtune and just finished syncing them and whatdyaknow it cleared up the idling issues, it now idles good and returns to 1300rpm when i drop the throttle. Order your morgan carbutune directly from carbtune.com, the shipping took 2 weeks and it was about 100 bucks. Excellent little tool.

 

[[email protected]]

i recently cleaned my carbs and it was idling weird. So i ordered me up a morgan carbtune and just finished syncing them and whatdyaknow it cleared up the idling issues, it now idles good and returns to 1300rpm when i drop the throttle. Order your morgan carbutune directly from carbtune.com, the shipping took 2 weeks and it was about 100 bucks. Excellent little tool.

Idle speed should be 1100 RPM

 

[SDB]

Before and after...