Carb Sync: Need help please

Was able to sync 1-2 and 3-4 but could not then make both pairs have the same reading by using the middle screw.

Any advice ?

Many thanks

 

are you turning the screw enoght times the threads are veery fine

 

Do you know that the middle screw is adjusting both 1 and 2 at the same time?

 

The middle screw is used to balance banks 1-2 and 3-4. It does NOT adjust 1 or 2. There are three screws used to sync. #1 is located between bank 1-2, #2 is located between bank 3-4 and #3 is between the two banks. You should balance 3-4 first since #3 is the reference carb (at least on the 650/750 models). Get them matched. Then balance 1-2. Once you have those balanced, then balance the banks against each other.
Do NOT confuse the idle set screw with the sync screw, they are in two totally different locations.
Htheyer, I'm not a carb guru or I'd spout out an answer for you bud. One of our local experts will ply you with a suggestion in a short while.

 

Thanks lowlifexj ...

 

Excellent Robert, thanks. Will give it a try starting with 3-4 this time ... hope it works.

 

Yes Lou627, aware of that ... thanks for the reminder. Will start with 3-4 per Robert's

 

The 3 Sync Screws on the Linkage can sometimes be very confusing.

The first Sync Screw is Number-1's Throttle Adjustment Screw.
Adjust the Number-1 Screw to Match Number-1 to Number-2.

The Number-2 Screw is the Throttle Adjustment of Number-2.
But, ...
Number-1 and Number-2 are married.
Therefore ... Adjusting Number-2 adjusts BOTH 1 & 2.

Three has NO Sync Screw.
The Throttle Plate of Number-3 is controlled by the Idle Adjustment Rod.

The Sync Screw of Number-4 is used to Sync Number-4 to Number-3.

When 4 & 3 are in Sync, ...
and, ...
When 2 & 1 are in Sync, ...
Adjust Number-2's Sync Screw to bring all four together.

 

Thanks Rick, will give it a shot this week end.

 

Better this time but still 1-2 not in sync with 3-4 ... anything else I should check ?

Many thanks

 

Hi htheyer, what tool are you using to sync your carbs ,just for interest sake. ........Cheers,Murray.

 

Carburetor Synchronizer (4 gauges) I bought from ebay. Search carb sync ...

 

When you are syncing 1and 2 to 3and 4, are you using the vac ports on 2and 3?
When I did mine with a homemade monometer, I messed up and used 1 and 4. My thought was if 1 & 2 are the same, and 3 & 4 are the same, then it shouldn't matter which ports I used as long as it was one from each side. But after a little less then success, I remembered that 3 is fixed and should be used as a "defult" for the rest.

I see that you have 4 gauges, but I would focus on 2 &3.

Disclaimer: I am not a pro, this is based off my personal experience.