throttle plate set screw

[firecarl]

I made a terrible mistake the other day on my 05 1200rt, i have always performed most maintance on previous bikes and looked forward to getting back into this routine with this bike, after 3 dealer services i felt ready to tackle a tune up, all went fine until i adjusted the throttle plate set screws during the carb sync, after realizing my mistake i called dealer and they stated bmw recommends new throttle bodies because they are adjusted at the factory, dealer thinks he can adjust these back into spec in the shop, i would like any input/ advise on this subject,

[Fergie]

Not sure about this but I would think you could measure the throttle plate clearance from plate to bore on the side you didn't adjust and set the other side the same. In the auto world this is called mean idle setting. After you do that the computer controls the idle. Then you sync them with one cable around 3500 - 4000 rpm.

[Ken H.]

Oh boy, suddenly it sucks to be you. On the R11XXxx series we had developed a procedure to rather long and laboriously recover from this boo-boo, but on the R1200xx I am not aware of anyone having come up with one. Nor have I researched it.

 

Did you diddle with both sides? If not, as mentioned I'd measure the internal bore clearance of the stock side, manually set the messed with side to match, then see what happens. If the bike still idles right or not.

 

Lacking that I might try setting each side to 3 MM of internal clearance and see what happens.

 

Failing that, I suspect it's time to get out the Visa card.

[Fergie]

Ken. Another thought I had was if he didn't mess with the other one he could bring both to a engine shop with a flow bench and adjust the bad one to the same cfm flow rate as the untouched one. This would probably be much cheaper than what BMW would charge to fix.

[firecarl]

thanks for all your input, unfortunately both sides got moved in the sync attempt, taking the t.b. off and adjusting is more than likely out of my skill range and i will leave that to the shop, i did find a price range for a new t.b. $600.00 each, i will see what the sop says this next week and if i have to pony up for new t.b will just have to look at it as an expensive lesson {read directions 4 times, adjust 1 time} thankfully my wife is understanding in these matters, not thrilled just understanding!

[Ken H.]

If you do end up having to pony up for two new TBs, try to get the old ones back. I might give you a little something for them. I'd like to have a set to experiment with to see what we can come up with for situations just like this.

[Fergie]

Does anyone out there know if you can set the throttle plates by a given TPS value so Carl doesn't have to drop a bundle for new ones.

[Ken H.]

I was having a PM discussion earlier today with another member here about that idea.

 

I'm going to look into it a bit more tonight, but as I recall (have to take another look at the diagram) the hexheads don't use a supply voltage to the TPS like the oilheads do. The BMS-K module doesn't look at return voltage like the oilhead's Motronic does. It just reads the varying resistance. Still, it might be an idea. I'll dig a bit more and post back.

[Ken H.]

Carl,

 

Realizing you are in totally uncharted waters here, but facing a $1500+ repair bill, here is what I would at least try...

 

First, I better get my terminology right, the throttle position sensor is called a DKP not TPS in “hexhead speak” and it reports to the ZFE module, not the BMS-K module. My bad.

 

It is a three-wire variable potentiometer. Because of its connector design I couldn’t get an easy connection onto its wires while connected. And I didn’t feel up to stripping back my wiring harness for this exercise. Disconnected I measured 5.6 v on all three wires of the connector coming from the ZFE module, but that doesn’t mean much with it disconnected anyway.

 

Anyway I think we can do this without actual voltage, just by measuring resistance. You’re going to need a pretty good digital meter to do this. First note the little retaining tab that has to be popped up and out before the release clip can be pushed in to get the connector off of the TPS. Oops, I mean DKP on the left throttle body:

 

 

Then across pins 2 and 3, the center and rear most pins, I measure 1.632 K ohms of resistance with the throttle body on its idle stop. With the resistance increasing as the TB is rotated open. Remember though, this is a sample of one. We’d have to measure a lot of bikes to come up with a good average ‘target’ resistance.

 

So I’d suggest:

 

1) Start with a warmed up bike. (Presuming it will run at all at this point?)

 

2) Set up to measure this resistance as shown here. (With the bike shut down):

 

 

3) Now adjust your idle stop screw until the resistance value is 1.632 K ohms.

 

4) For now, on the right side stop screw, just try to guess set it at physically as close as you can to where we now have the the left side locked to.

 

5) Reconnect the DKP and disconnect the stepper air bypass servos on both sides. We’ve got to get to a ‘purely physical’ adjustment point somehow, and disconnecting them is the only way I can think of to do it:

 

 

6) Connect up whatever you are using to adjust sync and start the bike. Now adjust the right side idle stop screw to get best at idle in sync. The bike will show an engine fault for now on the dash; just ignore it. Don’t touch the left side idle stop screw at this point!

 

7) Shut down the bike then reconnect the steppers. Start it back up and with a bit of luck (OK, a lot of luck) it will idle fine.

 

8a) Now, where to go next depends upon if you believe in doing above idle sync without the steppers ‘in the loop’ or not. If without them (my opinion), shut it down, disconnect them again, start it back up and adjust the above idle sync by adjusting the right side cable pull barrel adjustment at whatever RPM you choose. I use 2500 or so.

 

8b) If you don’t want to take the steppers out of the circuit, just adjust the right side cable with them connected.

 

If all of this doesn’t work, time to call the trailer I’m afraid.

 

If it does work out, everyone remember, step #8 above is the ONLY thing you need to adjust when doing a sync on a hexhead. All of this to try to get Carl out of a bad spot is decidedly not normal procedure!

 

Please post back how this works out for you. This is a valuable learning exercise where I don't think any of us have been on the hexheads yet. I would be good to know how on or off the mark this approach might be.

 

Good luck!

[Albert]

Ken,

I hereby nominate you for the "Going the Exta Mile" award. Nicely done my friend.

[Ken H.]

Ken,

I hereby nominate you for the "Going the Exta Mile" award. Nicely done my friend.

Thanks. I love messing with this kind of stuff, learning a bit as I go along. Besides, nothing else to do on a Monday night anyway.

 

But the real question is, can he fix his bike with this???

[firecarl]

ken thanks for all your effort and advise, its nice to know there are people out there that will go so far aout of there way for stangers, i am really humbled, ive been at work for the last 24 hrs so i just read this posting, i am starting to learn that these are not the bikes of old and are far more complicated than my feeble skills should attemp to repair, i have decided to drop the bike off at the shop and have the experts? fix my mistake, i will try to post again with any info the shop will let out about the settings so this info might be of use for others, if i do end up replacing t.b.s i will let you know they would be of no use to me other than maybe a nice pair of book ends for all my old repair manuels, thanks again

[Ken H.]

Well it's your call of course.

 

Anyone else want to intentionally mess up their throttle bodies so we can try this experimental theory out?

 

I would be interested though in a couple of people just measuring the resistance of the DKP (TPS) on a hexhead when the left TB is on its idle stop. So we can get a better idea as to what the average reading is.

[ADulay]

Ken,

 

Rest assured, the next time (actually it would be the FIRST) time I can get to those throttle bodies, I'll grab a reading for you of the resistance mark.

 

AD

[Albert]

Anyone else want to intentionally mess up their throttle bodies so we can try this experimental theory out?

 

If this happens I withdraw your nomination and proclaim them a winner.