carb sync

[handyandy64]

I'm trying to sync the carbs. No. 1, 3, 4 are the same 4.5. No.2 reads 5.5. I'm guessing that even though the readings are close, the are way to low. I believe they are supposed to be 8-9. This would mean I have a massive vacuum leak. I know they can come from many different places. Any suggestions?

[flyin900]

I don't think the readings specs in the Honda manual are relevant unless your using the exact same gauge set up that Honda tech's had back in the day. Getting everything close is the goal, not getting them to read as the manual indicates (hg) wise.
You may be able to tweak the #2 a little closer to the others average, yet everything on that side moves as you adjust each one individually.
I believe #3 is the reference carb and #4 adjustment is to balance the two sides (1-3) and (2-4) closely to each other.

To check for vacuum leaks I use a propane torch and waft it around the intake runners to see if anything changes in the RPM.

[Track T 2411]

On the propane torch, I believe he means an UNLIT propane torch...

[flyin900]

Oh come on Track... it makes it interesting!

Good catch though... as you never know.

[5speed]

On the propane torch, I believe he means an UNLIT propane torch...

NOW you post this..


My first attempt at syncing the carbs on my 76 I spent hours trying to get the gauges in the "green"..
I should have checked here first..instead I took it to my bike mechanic, it fell off the trailer, he was down 2 mechanics and it was going to be a while before he got to it.
He called me a few days later, told me about the 82 standard he had that he would sell me for $500..
Soooo the 76 still doesn't have synced carbs and is currently resting in the shed with my 78.
How is that for a "can't sync my carbs" post.

[flyday58]

The Motion Pro and Morgan Carbtune I have don't even have numbers, just reference lines.