broodwich
Well-known member
Okay let me just start by saying there is already a great article on how to do the throttle body sync by Warchild on FJRTech.com. Plus you could follow the instructions in the factory service manual. I'm not trying to replace either of those resources here. I just thought it might be helpful to have some more detailed images of the thottle body caps and the throttle body air adjustment screws. Things are packed in pretty tight under the gas tank and it might be tough to identify these items the first time you do this procedure.
These pictures were taken with the gas tank tilted back and held up with some rope tied to the rear luggage rack. Here is a photo of how I hold the tank up.
What you can't see in the photo is I also loop the rope around the metal flange at the top of the tank just to make sure I couldn't nudge the rope loose and drop the tank on my hands or something.
The photos of the caps and air adjustment screws shown below for cylinders 1 and 2 where taken from the left hand side of the bike, the clutch side. The photos for cylinders 3 and 4 were taken from the right hand side of the bike, the throttle side. Also, these photos were taken after I had removed the left and right side rubber covers that sit below the gas tank.
Left Side Photos
Cylinder 1 Air Adjustment Screw
Cylinder 2 Cap
I don't know how I missed taking a photo of the cap for cylinder 1 but you can clearly see the cap in the photo below.
Cylinder 2 Air Adjustment Screw
Right Side Photos
Cylinder 3 Cap
Cylinder 3 Air Adjustment Screw
Cylinder 4 Cap
Cylinder 4 Air Adjustment Screw
I use the Morgan Carbtune II calibrate the throttle bodies. The service manual calls for the vacuum pressure to be between 220 and 280 mm Hg, the middle of that range would be 250 mm Hg. The solid lines on the manometer are spaced at 20 mm apart. Each of the dashed marks in between a solid line are 5 mm apart.
Here is a photo showing my throttle body measurements prior to making any adjustments.
Before making adjustments there was a 20 mm difference between cylinders 1 and 2, a 15 mm difference between cylinders 2 and 3, and a 5 mm difference between cylinders 3 and 4.
Here is what the Carbtune looked like after I made adjustments.
The service manual says that difference in vacuum pressure between two throttle bodies should not exceed 10 mm Hg. After making my adjustments cylinders 1, 3 & 4 were all sitting at about 245 mm Hg with cylinder 2 sitting a little bit high at 250 mm Hg. Still within spec at less than 10 mm difference between any two throttle bodies
Edit:
I just uploaded my first YouTube Video ever. I have titled it, the "Worlds Most Boring FJR Video" ever. I filmed the whole 12 minute process of syncing my throttle bodies. Don't worry I edited the video down to just over 2 minutes. So if you ever wanted to see what the Carbtune looks like in action, and I use the word "action" quite loosely here, check out the video I uploaded.
These pictures were taken with the gas tank tilted back and held up with some rope tied to the rear luggage rack. Here is a photo of how I hold the tank up.
What you can't see in the photo is I also loop the rope around the metal flange at the top of the tank just to make sure I couldn't nudge the rope loose and drop the tank on my hands or something.
The photos of the caps and air adjustment screws shown below for cylinders 1 and 2 where taken from the left hand side of the bike, the clutch side. The photos for cylinders 3 and 4 were taken from the right hand side of the bike, the throttle side. Also, these photos were taken after I had removed the left and right side rubber covers that sit below the gas tank.
Left Side Photos
Cylinder 1 Air Adjustment Screw
Cylinder 2 Cap
I don't know how I missed taking a photo of the cap for cylinder 1 but you can clearly see the cap in the photo below.
Cylinder 2 Air Adjustment Screw
Right Side Photos
Cylinder 3 Cap
Cylinder 3 Air Adjustment Screw
Cylinder 4 Cap
Cylinder 4 Air Adjustment Screw
I use the Morgan Carbtune II calibrate the throttle bodies. The service manual calls for the vacuum pressure to be between 220 and 280 mm Hg, the middle of that range would be 250 mm Hg. The solid lines on the manometer are spaced at 20 mm apart. Each of the dashed marks in between a solid line are 5 mm apart.
Here is a photo showing my throttle body measurements prior to making any adjustments.
Before making adjustments there was a 20 mm difference between cylinders 1 and 2, a 15 mm difference between cylinders 2 and 3, and a 5 mm difference between cylinders 3 and 4.
Here is what the Carbtune looked like after I made adjustments.
The service manual says that difference in vacuum pressure between two throttle bodies should not exceed 10 mm Hg. After making my adjustments cylinders 1, 3 & 4 were all sitting at about 245 mm Hg with cylinder 2 sitting a little bit high at 250 mm Hg. Still within spec at less than 10 mm difference between any two throttle bodies
Edit:
I just uploaded my first YouTube Video ever. I have titled it, the "Worlds Most Boring FJR Video" ever. I filmed the whole 12 minute process of syncing my throttle bodies. Don't worry I edited the video down to just over 2 minutes. So if you ever wanted to see what the Carbtune looks like in action, and I use the word "action" quite loosely here, check out the video I uploaded.
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