Unable to sync carb

[megablok]

I have an '06 RSTD. Recently, I separated the carbs, cleaned them and rebuilt it. However, I'm unable to sync the carbs because it's not been possible to reduce the idling RPM. 

With the carbs reassembled, and off the mcycle, I first adjusted Philips stop screw #1 between carbs 1&2 and Philips screw #2 between carbs 3&4. After that, I adjusted the flathead screw and visually synced the butterfly opening between carb banks 1&2 and 3&4. I do this generally to get to a good starting point to do final adjustments using Carbtune. Also, adjusting the #3 shows how close the TPS can get to idling screw. 

However, I'm unable to get the RPMs down to the 1000 range. 

I would appreciate any suggestions. Thank you. 

 

Thanks to the members for these excellent articles:

 

 

Edited April 19, 2021 by megablok
Added Links that are useful and relevant.

[RDawson]

Are they seated correctly? Vacuum leaks can cause it to go high. Also check your cable routing that they are closing. 

[megablok]

Thanks Dawson.  I took the carbs off, reseated it and checked it. They seem to be seated fine....

 

[Marcarl]

Most likely there is a butterfly staying open. One open butterfly can do it.

[RDawson]

Are all 4 choke/enrichers closing fully?

[Freebird]

I've seen that happen when the sync screws are way off.  You might try adjusting them some and see if the idle will come down.

[megablok]

Based on the suggestions here, I took the carbs off and closely inspected them again.  Found the following issues:

1. The Joint Air Cleaner 2 (4XY-14463-00-00) was damaged. (have ordered a new part.  Its coming in next week.  
2. Two of the four Joint Air Cleaner 1 (4XY-14453-00-00) were damaged.  I have received the new part. Thank you @RDawson for the suggestion.
3. The Stop Screw set springs (4KM-1490K-00-00) were damaged when I reassembled the carbs (ugh).  I have received the new part.  Thank you @Freebird for the suggestion.  

@RDawson, the choke enrichers feel mushy when I pull on the choke know.  They are engaged fully.  Is that what it feels like when cleaned?  It used to be really tight before cleaning.

@RDawson.  I am replacing two of them (item 2)  - I have included a picture.  I am not sure if this is a problem.  But since it appears worn, I am replacing them.

@Marcarl, when I adjusted the sync screws before installing it on the mcycle, the butterfly on carb 1 seems more open than the others.  I thought it will get handled during sync when the engine is running.  I am going to separate the carbs one more time and reassemble them carefully and see if it works.  Maybe I missed something.  

I plan to  sync the carbs again next weekend after I have all the parts and post the updates again.  

 

[megablok]

Finally finished on this project. I visually balanced the butterfly openings on the carb before installing it on the mc. Worked like a charm. Changed out a number the rubberized parts. Have a weird noise sometimes - I've posted it on a different thread. Hopefully someone will answer that. 

Love this mcycle and the forum!

[luvmy40]

In the future, bench sync with a strip of business card stock or a feeler gauge to start with the butterfy valves all at the same position.

[megablok]

Thats a great idea.  Will do that next time.  Thank you.