New member with TB balance question

Hi everyone, my first post on this forum.

I've been the owner of a 2005 R1200RT for the past 12 months, my first BMW after a number of Triumphs, Hondas, Cagiva V Raptor etc over the last 35 years.

This week I gave my bike its annual service, and also did the tappets & rocker arm end float.

I made a manometer & tried to do the throttle body balance. I've seen mention of first checking for cable free-play, how do I do this?

I connected the manometer & the right cylinder was sucking a fair bit more than the left, I started trying to adjust the right hand cable, as I was doing this there was a light 'crack' sound & I noticed the black plastic part that the adjuster goes through seemed to have dropped a little, what does this plastic part do, & have I broken it, or has it just perhaps moved from its original position? I didn't seem able to put it back to where it should be.

I ended up having to adjust the cables on both sides to get the balance right at 3-4k revs.

Many thanks.

Welcome bobbob455 -

You wrote:

I connected the manometer & the right cylinder was sucking a fair bit more than the left, I started trying to adjust the right hand cable, as I was doing this there was a light 'crack' sound & I noticed the black plastic part that the adjuster goes through seemed to have dropped a little, what does this plastic part do, & have I broken it, or has it just perhaps moved from its original position? I didn't seem able to put it back to where it should be.

As usual, I would welcome thoughts of the other members on this!

Morning bobbob455

I made a manometer & tried to do the throttle body balance. I've seen mention of first checking for cable free-play, how do I do this?--Just grab the cables at each throttle body & make sure they have a little slack. If they both need more then there is an adjuster up by the twist grip (under the rubber boot). If just one side is tight then adjust that side if you need to loosen then adjust from there.

I connected the manometer & the right cylinder was sucking a fair bit more than the left,--drawing more or less? The more air it draws the lower the fluid column on that side (most people get this backwards)

I started trying to adjust the right hand cable, as I was doing this there was a light 'crack' sound & I noticed the black plastic part that the adjuster goes through seemed to have dropped a little, what does this plastic part do, & have I broken it, or has it just perhaps moved from its original position? I didn't seem able to put it back to where it should be.--If you broke the plastic part (A in picture below) then that is serious. Is it possible the throttle adjuster just snapped in & seated deeper in that plastic piece (that happens if the cable was pulled up out of the adjuster--Usually when changing the air filter)

I ended up having to adjust the cables on both sides to get the balance right at 3-4k revs.

Many thanks.-- You should have ONLY needed to adjust one side. Did you adjust the R/H side THEN have the cable snap deeper into on the TB plastic part? (you have to make darn sure that the cable are fully seated before starting any adjustments.

You didn't turn the sealed base idle screws did you? Those should never be touched, so if you moved them try t put them back where they were (paint marks lined up).

WOW, looking at the link I hope not. I was able to balance the throttle bodies ok.

The fluid in the right side of the manometer went up, so that's the side drawing less? Yeah, I did get this the wrong way round. I assumed if it's sucking the fluid up the tube then it's drawing more, obviously not, thanks for that 👊

I didn't move the small screw with white paint on (thankfully).

There is a plastic cover where the cable goes through, & the base idle screw is. It seemed that cover 'dropped' a couple of mm when I heard the slight crack, could this cover just have moved/cracked? & not the plastic cam ?

 

There is a plastic cover where the cable goes through, & the base idle screw is. It seemed that cover 'dropped' a couple of mm when I heard the slight crack, could this cover just have moved/cracked? & not the plastic cam ?

Afternoon bobbob455

If the cable bracket (shown in picture) is good & solid then probably the plastic debris cover is just a bit loose (on some bikes they can move around a little)

If the above idle TB balance holds true after a few rides then you are probably good-to-go)

A little trick that I personally use: I run a hose from the lower nipple on each TB up under the seat & zip tie to the cross tube. I then run the purge hose up to that location & plug it into one of the TB hoses then plug off the other hose. (just like stock but connections are now under seat)

Then after riding the bike long distance & getting it real hot-- (then without turning engine off)-- I just use my spare key to remove the seat, then use a hemostat (or clamp) on each hose coming from the TB nipples (to keep sealed off until manometer is hooked up)-- I simply uncap each hose then hook up my manometer & do a quick idle & part throttle balance check (it never seems to be off once set properly on a real hot engine-- but it is re-assuring to verify this now & then)

Brilliant advise mate. I'll connect short hoses as you described & keep checking it. It'll be a shame if it's cracked, as it's running sweeter than ever since I did the tappets & TB balance.

I take it I can remove the dust cover to get a look at the cable bracket without removing the throttle bodies?

Cheers

Brilliant advise mate. I'll connect short hoses as you described & keep checking it. It'll be a shame if it's cracked, as it's running sweeter than ever since I did the tappets & TB balance.

I take it I can remove the dust cover to get a look at the cable bracket without removing the throttle bodies?

Cheers

Morning bobbob455

Yes, those covers can be lifted (won't come off without removing the cables though)

Problem is, it's been a long time since I have accessed the TB cams on the 05 1200rt so I can't remember if those covers just slide up or there is little clip holding them on.

If yours won't slide up easily then look for a clip that is holding them in place (careful so you don't break or crack the cover)