R1150GS throttle sync

Discussion in 'GS Boxers' started by westcoastjb, Jan 9, 2019.

  1. westcoastjb

    westcoastjb Adventurer

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    I'm trying to figure out how to sync the throttles on my 2001 R1150GS... I have the very terse and confusing Haynes manual, which doesn't seem to apply to this bike's configuration. It shows nipples or vents on the bodies with little plastic caps, but on mine on the left side there is a bolt where the manual shows a vent, while on the right side there is a vent in a forward position (underneath), but it a has a line attached to it. I can only assume the latter is a throttle feedback sensor and the bike probably will not only not run without it, but will also signal a motronic fault that will need to be cleared. I've looked around but can't seem to find anything of particular relevance... How to best hook up a Twinmax?

    Also, is it critical to slacken the adjusters at the handlebar prior to synchronization? Only the Haynes manual seems to mention this.
    #1
  2. lewisjr1

    lewisjr1 Long timer Supporter

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    #2
  3. roger 04 rt

    roger 04 rt Long timer

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  4. westcoastjb

    westcoastjb Adventurer

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    Pics! On closer inspection I realize both sides have hoses, but only the left side has the rear end bolt... Left side overview:

    [​IMG]

    Left side close up:

    [​IMG]

    Right side:

    [​IMG]
    #4
  5. ridepjride

    ridepjride Migrant

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  6. westcoastjb

    westcoastjb Adventurer

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  7. Jim Moore

    Jim Moore Harsh and colorful

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    You pull those hoses off the bottom of the throttle bodies and connect your manometer to the ports.
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  8. ridepjride

    ridepjride Migrant

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    Check your PMs.
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  9. Jim Moore

    Jim Moore Harsh and colorful

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    Hey OP, where are you? I can almost guarantee there is someone within 50 miles who will come to your house and show you how to do it.
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  10. Dan Cãta

    Dan Cãta Long timer Supporter

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    Is that hose connected to the carbon canister or is it the hose mode that connects the intakes so that it adjusts/evens the vacuum between them?

    Dan.
    #10
  11. Reno1

    Reno1 Can't get lost if you don't know where you'er goin

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    Hi just wanted to weigh in here. I have a 2001 R1150GS. DO NOT TOUCH the throttle position stop screw. These are set at the factory on a flow bench so that the pair of throttle bodies one your specific bike have the same volume of air flowing through them. They are a matched set. Messing with those screws will change the air flow per throttle body. The only screw you adjust for idle is the large brass air screw. See pic below.

    In my opinion the throttle body on the left side has been installed upside down you need to take it off and flip it over (the fuel injector is supposed to be on the top side not the under side) Also reroute the throttle cable correctly. See the pic below which has the throttle body installed correctly. When performing this procedure do not remove the Throttle Position Sensor the little black plastic box attached to the throttle body (you need a special tool to reset it if you take it off). Instead Remove the electrical connector that is attached to the Throttle Position Sensor.

    In regard to the charcoal canister, I have removed mine because over time the charcoal can back flush into the fuel system over time, I would highly recommend it. Chris Harris has a good and might I say entertaining “how to “video.

    Adjust all the cables as specified in the BMW instructions provided previously in the chat string (including the cold start cable). Attach you synchronizer to the little brass vacuum ports. Adjust the large brass air screws to synchronize the throttle bodies at idle (my bike idles best around 1050 to 1100 RPM). You may need to let you bike cool after this depending on how long it takes you to synchronize the idle.
    After you have the idle synchronized you can begin the second synchronization holding the throttle at about 2500 rpm. The reference throttle body is the one on the left side (with the throttle position sensor). You adjust the throttle cable adjustment on the right side throttle body to bring the throttle body into synchronization with the reference throttle body on the left side (all right and left reference are made as you are sitting on the bike). IMG_2095.jpg IMG_2097.jpg IMG_2098.jpg IMG_2096.jpg

    Attached Files:

    #11
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  12. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    :scratch

    The throttle body is fine. The photo is from the bottom. It is impossible to install it upside down.
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  13. Dribblers Dad

    Dribblers Dad Adventurer

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    You see in the middle picture of the left side throttle body there is a thin brown wire, this should have a ring terminal crimped on the end and this is fastened to the allen screw ( bolt ) at the back of the throttle body. This is probably a reference earth for the TPS signal as the throttle body is electrically isolated from the rest of the engine.

    I`m wondering if a previous owner has tried to be clever and has fitted the rubber hose to both the front spigots on the TB`s thinking that this will balance them out? Pull both ends off and blow through, see what comes out the other end :)
    #13
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  14. Jim Moore

    Jim Moore Harsh and colorful

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    Good eye!
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  15. Reno1

    Reno1 Can't get lost if you don't know where you'er goin

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    This is a pic of the ground wire and where it is located on the left throttle body. Also sorry about the comment regarding the throttle body being up side down it was difficult to determine the orientation of the photo. IMG_2100.jpg
    IMG_2123.jpg
    #15
  16. Reno1

    Reno1 Can't get lost if you don't know where you'er goin

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    Also how do you enter the description of the photo you insert into a reply, can’t seem to figure that out
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  17. Steve W.

    Steve W. Boxer Pilot

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  18. westcoastjb

    westcoastjb Adventurer

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    I'm the original owner; bought the bike from Cal BMW (now Cal Moto), Mr Prager himself. It has only ever been serviced by Cal BMW and Romeo at SF BMW MC. It has 34.5k on the clock.

    It's almost as if someone did a throttle sync at some point and left the hoses attached... :hmmmmm(Edit: no, just kidding. They both go into the bowels under the tank. They're zip tied in place.)
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  19. westcoastjb

    westcoastjb Adventurer

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    Good call on the brown lead... it's indeed on the rear bolt, so it being the TPS ground reference makes perfect sense!

    Left throttle body top view...

    [​IMG]
    #19
  20. JimVonBaden

    JimVonBaden "Cool" Aid! Supporter

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    Normally they go to a valve that controls vacuum in and out of the carbon canister. You can simply unplug them and use caps on the throttle bodies, then remove the carbon canister.
    #20