Throttle bodies syncing procedure

Delta

Well-Known Member
Hi fellers I've just bought myself a Morgan carbtune pro so I can check and adjust my throttle bodies. Can someone tell me the correct way to sync them please. I was told something about body number 3 you leave and synce the others to this one. I've never done it before so help would be very much appreciated indeed.
Thanks fellers

Delta
 
I don't have a photo of it, but you adjust 1 & 4 with their individual set screws and 2 & 3 are adjusted with a single screw in the middle. I'll have to see about some photos to explain.
 
I don't have a photo of it, but you adjust 1 & 4 with their individual set screws and 2 & 3 are adjusted with a single screw in the middle. I'll have to see about some photos to explain.

Ok that helps a lot more than me knowing nothing. What vacuum HG numbers am I looking for or is that irrelevant really? I just want to do it spot on.
Photos would be excellent fella.
 
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Just to add I've got the graves verlosity stacks waiting for me at parcel force. In gbp it has cost me £77.50 for the stacks plus USA postage at £25.50 the the customs did me for another £27.88
No idea what you guys pay but I've got them now.
I will fit them then sync the throttle bodies.
I can't wait to get it all done so the bike runs nice and crisp.
Any joy on those photos fella?
 
Ok... This is a picture of a TB intake removed so you can easily see where these are located. There are 4 individual vacuum adjustment screws but you will be working with only the two indicated with the GREEN and not touching the two indicated with the RED. The middle screw highlighted in GREEN is what you will use to balance #2 and #3 cylinders.

Some notes first:
  • Adjusting any screw may cause the meter to change for OTHER cylinders.
  • You may need to go back and re-adjust cylinders you'd already adjusted.
  • Do NOT adjust the bike with the temp over 170. Shut it down and let the bike cool off. Be paitent and do not rush this!
  • As the bike's temp goes up, the numbers you are working with also rise. Don't try to only shoot for the magical 22. It is more important that these are balanced, not all at a magical number.
  • REMEMBER: Do not touch the individual screws for #2 & #3!!! Use only the middle "spring-tension" screw for these two!


  1. Remove the plastic plugs from the vacuum hoses between cylinders 1 & 3 and connect the guage positions 1 & 3 accordingly. Now do the same for #2 & #4.
  2. Start the bike and warm to 140 degrees. Adjust idle (if needed) to 1250 RPMs. (A couple of high volume fans will help unless it is very cool outside when you do this. You don't want to be over 170 degrees and making adjustments.
  3. Adjust the middle screw to balance #2 & #3. Turning one way will lower one and raise the other. Turning the other way reverses this.
  4. Gently roll the throttle to about 2500 RPMs and gently roll back. Check #2 & #3 again.
  5. With 2 & 3 balanced, adjust #1 to match. Do the same throttle step and check again.
  6. With 1, 2, & 3 balanced, now adjust #4 to match. Same throttle steps again.
  7. Readjust any screw as needed.

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Just completed the sync with help from this thread, the FSM leaves a lot to be desired concerning this procedure.

Final reading20210516_164047.jpg

Tool used to make all adjustments20210516_164308.jpg

Carbtune hooked up 20210516_164142.jpg

Fans to keep the temp in range20210516_164244.jpg
 
Follow the manual, there is a reason they say not to touch the screw in the middle, the one that has white paint on it. Only use the brass screws for the sync.

1&2 throttle plates are on a common shaft, 3&4 are also on a common shaft. They are synced from the factory so that the 2 shafts are turning in sync with each other.

They are NOT synced using vacuum, when you adjust that screw you are putting them out of sync.

Each TB has an Idle air bypass which are adjusted by the brass screws, which adjusts the idle air so that all 4 cylinders are getting the same amount of air at idle.

I am not sure how playing with the painted screw came about, but it is WRONG.
 
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