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First throttle body adjust


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Started feeling guilty, decided to try. Low speed adjust was by the book (internet bmw riders r1100 pdf). Had trouble getting any slack on the right side throttle cable knurled adj. but I found a little, left side no slack. Is this correct? Anyway,when I come off idle,not even 1300rpm, right side vacuum peaks the manometer, left side goes negative. If I disconnect the right side there is vacuum on the left and it, of course peaks. I even waved the owners manual in front of the headlight but bike was unimpressed. Turned it off, added adjustment to the right side knurled nut but no difference. I can't do it with the engine running because it will suck everything in the engine. It seemed to be running very smoothly before I started, you know that old saying about bliss and ignorance? So, what am I doing wrong?

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You need to go back and adjust the LHS so you have the correct ammount of slack with the fast idle lever OFF and the throttle closed ( adjust only the cable adjuster ).

Then make sure you have the right side adjusted to about the same amount of slack as the LHS.


Then once you have slack in the throttle cables on both sides, redo the idle adjustment with the BBS.


Then go on to adjust the fast idle using only the RHS cable to even out the balance between the two sides, this should leave you with an even balance both sides, but check both at idle and again at your fast idle setting.


Ride and enjoy

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Thanks Nigel, I just rechecked the valves and they are consistant side to side. I'll try your suggestion tomorrow. Right now it's time for tullamore dew.

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How many Kms/Mls on the clock?


94,000 miles. Sprayed carb cleaner on the left side today and saw the left side manometer rise for the first time. Sprayed on the right, rpm drops 200.Either a leak at the manifold or leaky throttle bodies or both :P

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How many Kms/Mls on the clock?


94,000 miles. Sprayed carb cleaner on the left side today and saw the left side manometer rise for the first time. Sprayed on the right, rpm drops 200.Either a leak at the manifold or leaky throttle bodies or both :P



Left side has a leak....

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Suspect a TB to manifold leak, try reseating the TB in the manifold and retighten.


If you spray locally around the TB joints this should help pinpoint the leak area. Its possible the LHS TB has been disturbed in its mount.


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Don't let that carb cleaner confuse the cross side balance issue for you.


The cross side above-idle balance is strictly an air flow issue so adding carb cleaner either momentarily seals the throttle shaft/bushing normal leaks or raises the engine RPM.


Keep in mind that the IDLE balance is separate from the ABOVE IDLE balance.


SO, go back & start your balance adjustment over--


First thing --(with choke OFF)-- make sure you have some cable slack in BOTH SIDES. You can usually get this slack by using the cable adjuster up by the twist grip. (bottom line here), YOU NEED CABLE SLACK at the TB's IN BOTH SIDES before even starting the TB balance.


Once you have cable slack IN BOTH SIDES-- next do a preliminary adjustment on the lower cables at the TB's so BOTH side throttle cams lift off their idle stops at the same time (get close as possible).


Then verify that BOTH SIDE TB cams hit their wide open stops at the same time (close as possible).


Once the you have cable slack at idle (a MUST) , & have the TB cams lift of the stops at the same time & hit wide open at the same time then you are ready to set the balance.


So hook up your balance gauge (or U tube) then start engine & allow to warm up (use fans on front of engine).


Once warm then use the BBS screws to get even engine IDLE vacuum side to side. If the idle balance comes in with the BBS screws around 1-2.5 turns out from seated then you probably don't have any vacuum leaks.


Next, use the twist grip & slowly open the throttle while watching the balance gauge or U tube liquid heights. The low side is the side with the throttle plate OPEN the farthest (open plate=lower vacuum) so back the cable adjuster furrel off a bit on that side.


Just keep in mind the lower the vacuum on one side means that side has a more OPEN throttle plate (opposite of what most people think)


Once you get the off-idle balance 1500-2500 RPM range close then shut the engine off & re-verify that both sides lift off their idle stops at the EXACT TIME & both sides hit their wide open stops at the very same time.


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I never intended to be a mechanic. There were always techs around to service my stuff. Then I moved to Avon where you drive 50 miles to buy underwear and I bought this damn beemer..

So, DR, I followed your instructions like a bible. First surprise was the cable from the twist grip to the left TB had no adj. at the grip. When all the adj. was taken out on the TB I had, at most, 1/8"at the pully. but it was slack of sorts and the idle stop was at the stop. Idle balance was easy with 1 1/2 turns on the left and 2 on the right so I guess the carb spray was misleading (but clean TBs). After setting up to make sure both TBs opened and closed together to both stops I actually got above idle balance at 2000 rpm but boy it is touchy. So once again thank you, keep the tutorials coming. And Nigel, lets have a Dew....



DR, I forgot to say your comment about lower vacuum with open throttle helped me understand what direction to go with the adjustments.

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