Throttle Body Sync question

Joined
Sep 4, 2013
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8,108
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Cleveland
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2010 ST1300
I've read quite a few posts that mention syncing the throttle bodies. What exactly is synchronized? My shop manual says not to touch the painted screws on the throttle bodies because they are factory set. If you are talking about carbs on the older bikes, then I understand this. I looked in my manual (fuel injected bikes) and it only mentions Starter Valve Synchronization (page 5-134) - is this what is being discussed?
 

wjbertrand

Ventura Highway
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Feb 8, 2005
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Ventura, CA
You are actually syncing the starter jets not the throttle bodies. There is no adjustment for the throttle bodies.


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DavidR8

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May 31, 2017
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Vancouver Island, British Columbia
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2013 BMW R1200RT
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8968
Yes, Jeff is spot on. The adjustment is to the starter valves which allow a small amount of air to enter the throttle body underneath the throttle plates.

I didn’t understand what they did till I found this video.
https://youtu.be/KTocWBlhMGs


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Last edited:
Joined
Jan 8, 2011
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7,062
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Arizona
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2007 Honda ST1300A
The throttle bodies are adjusted at the factory and should not be altered.
The starter valve procedure is what everyone on this forum calls the TB sync (sic)
Thanks for posting the video David.
 

Happy Rob

Rob
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Jun 17, 2015
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55
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CBS, Newfoundland, Canada
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2004 ST 1300
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8931
My 05 ST1300 is not idling properly. At cold start only revs to about 1600 for 4 mins or so. Then when warm idles at about 1000. My other ST1300 revs much higher when cold then purrs at 1300 when warm. My question.... do I just turn up the idle adjustment on right side of gas tank or should I do starter valve sync ( throttle body sync). I don't have tools for the sync so would have to actually pay someone else to do that. Would pain me to allow someone else to work on my baby but if that is what's best, I will!!!
 
Joined
Sep 3, 2016
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LSAC, AB & Indio, CA
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2005/06/07 ST1300
The problem idle machine is probably not the sync, although I would do that as well. I think the coolant is not getting to the wax valves and supplying temp to them, so a coolant level check, perhaps a flush may be in order. Also there is a post on here about the high idle and a blockage in the coolant line that prevented the wax valves from getting warm. I would set your warm idle to 1050 by the screw in the right cowling to start, and check coolant flow. A sync is a great thing as well.
 
Joined
Sep 3, 2017
Messages
107
Location
Edmonton, AB
Bike
2008 ST1300A
My 05 ST1300 is not idling properly. At cold start only revs to about 1600 for 4 mins or so. Then when warm idles at about 1000. My other ST1300 revs much higher when cold then purrs at 1300 when warm. My question.... do I just turn up the idle adjustment on right side of gas tank or should I do starter valve sync ( throttle body sync). I don't have tools for the sync so would have to actually pay someone else to do that. Would pain me to allow someone else to work on my baby but if that is what's best, I will!!!
A sync can be done using a DIY manometer. Check google and you will see many different shapes and methods. All you really care about is making certain the vacuum levels are equal in all.

My own hacked together variant uses clear tubing, plastic tees, and automatic transmission fluid mounted to a piece of MDF board. All told I believe $18 canadian was spent, with complete success.
 

wjbertrand

Ventura Highway
Joined
Feb 8, 2005
Messages
4,407
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Ventura, CA
My 05 ST1300 is not idling properly. At cold start only revs to about 1600 for 4 mins or so. Then when warm idles at about 1000. My other ST1300 revs much higher when cold then purrs at 1300 when warm. My question.... do I just turn up the idle adjustment on right side of gas tank or should I do starter valve sync ( throttle body sync). I don't have tools for the sync so would have to actually pay someone else to do that. Would pain me to allow someone else to work on my baby but if that is what's best, I will!!!
First thing I'd do is adjust the idle (with the screw on the right side) on your other ST1300 so that it's at about 1100 RPM warm, sounds like it's idling too fast. On the '05 I'd just tweak the warm idle up to 1100 RPM. I'll bet they act pretty similarly after that.
 
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