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TPS Alignment, Idle Speed Adjustment: Beyond Zero=Zero

R1100RT TB Sync status...

So, abandoning the Zero=Zero procedure, I set the fully closed position on LTB to .25V on the TPS, and then tweaked the Left stop screw to .34V and locked it. Matched the right side screw as best I could. Both BBS out to 1 1/2 turn open.

Started up and idle was lower (about 1000 rpm) and vacuum balance was pretty good. (The bike ran much smoother than with the 0=0 attempts.) Tweaked the right stop screw to balance manometer. Noticed that at higher RPM's the left side was consistently drawing higher vacuum than right. I tweaked the BBS to up the rpm to ~1100 and got very nice idle with balanced manometer. But, at high RPMs I keep getting more draw on left than right and it keeps climbing as I stay at the higher RPM setting.

I did try playing with the right side screw a bit to see the effect at higher RPMs, but the left side keep pulling more vacuum.

Any thoughts on were to go from here?

Pat
 
Once you use the bbs screws to set idle you’re done with them. Assuming your cables are tensioned properly, and at that point you should NOT touch the TPS, BBS or throttle stop screws. If it’s drawing more vacuum on the left at 2500 rpm you should slightly relax the right TB cable tensioner to slightly retard its opening. Do you see that step in the procedure?
 
Last edited:
roger 04 rt said:
Once you use the bbs screws to set idle you’re done with them. Assuming your cables are tensioned properly, and at that point you should touch the TPS, BBS or throttle stop screw. If your drawing more vacuum on the left at 2500 rpm you should slightly relax the right TB cable tensioner to slightly retard its opening. Do you see that step in the procedure?
Click to expand...

Pretty sure you meant should NOT touch.
 
Okay, so let me get this straight. Your advice is to proceed with the procedure. Hmmm, yes, that sounds like a good idea. I think I will try that this time. :banghead

Thanks,

Pat
 
Got it!

After going through the whole procedure this time I was able to get nice idle speed, and good vacuum balance at idle and higher speeds. Pretty touchy adjustments, but it looks good on the manometer. All locked down and ready for test ride.

I'm going to tear out from my binder the Zero=zero guide and replace it the one that is a quarter volt higher.

Just for reference, are both stop screws normally locked with blue compound or just the left one?

Thank you for all the information and help on this Roger!

Pat
 
After buttoning it all back up and doing the test ride, I'm noticing more vibration at higher speeds than before, feeling it in the handlebars and seat, not terrible but more than before. Idle also seems to be hunting around a bit.

I do believe the 250mV starting point was the right thing to do because when I used the 0=0 before, my BBS were nearly all the way closed to get the idle down where it should be. With 0=250mV my idle was very close to 1100 with the BBS's at 1 1/2 turns open, needing only minor adjustments to get correct idle and balance.

I had equal vacuum on both sides at idle and higher RPM when I finished the adjustments. Assuming my vacuum balance didn't change for some reason, what might explain the vibration I'm feeling now?
I'm thinking of cleaning the fuel injectors and recheck vacuum next time I have it apart.

On that note, what does the voltage waveform to the fuel injectors look like? (Voltage level, pules duration, and f = RPM/120?) I was thinking of making a test/cleaning drive circuit using a 555 timer and MOSFET...

Thanks,

Pat
 
The first thing that comes to mind is that your 2500 rpm balance moved.

The pulses are 2 mS at idle and about 8 mS at full throttle. On the Oilhead they get pulse with each rotation of the engine—twice per 4 stroke cycle.
 
You can spend a lot of time trying to get the perfect idle.

If your tune is good, plugs, valve adjust, air filter, fuel filter etc., I go straight to my 4000 RPM balance. I spend more time there than at idle.

If my idle is a little off but I get a good hookup off the line, I don't really care that my Oilhead runs like an Airhead.

All the BS about zero-zero, the perfect BBS settings and TPS voltage really don't matter when you want to be at cruise speed and have a nice cruise.

When your idle sucks, doesn't pull off the line nice, I haven't seen any mention so far that the BBS seats accumulate crap or that a bad ECU ground can contribute.

An Excel spreadsheet can't help if you don't take care of the basics first.
 
Another odd thing comes to mind, particular to my bike and peculiar to others.

I have no explanation but, when my oil level is above the half way mark in my sight glass, I get an odd buzz at speed. There is no rhyme or reason that I can think of but other Oilheads that my buddies own report the same things.

The other thing, I had a fantastic summer, bike ran perfect until I got into it one day. Grabbed all the throttle I could, took off nice then I got the vibes. Nothing I did made it go away.

Since my babe was do for some serious TLC, I pulled the driveshaft. Out of phase almost 30 degrees and 1/2" longer than it should be. I spun the hub.

If you look at the whole picture, start at the basics, a snap shot of a spreadsheet is just that, a snap shot.
 
Thanks for the extra info. I'd like to tinker with it more if I didn't have to pull all that plastic every time! Next time open I think I'll try cleaning fuel injectors and replace the cam chain tensioner. Probably due by now (80K)...

I'll think I'll go easy on the throttle after hearing about that driveshaft.

Also, I'm getting chills just sitting here thinking about going 4000 RPM in Manitoba!!

Pat
 
Data point. I just bought an unbelievably well taken care of R1100RS. The prev owner did say he had done the Lentini zero = zero. I found voltages at idle and closed throttle plate that confirm that.
I did the procedure outlined in this thread and it seems to work well. The BBS are at about 2.5 turns to achieve good balance at 1100 RPM. Maybe it is noted elsewhere but it only took about 3/4 turn of the throttle stop screw to go from 250mv to 342mv. The right was easy to match to the left by also setting at 3/4 and then balancing with ATF sticks with BBS equal. Little tweaks of the BBS resulted in seemingly perfect idle.

Has anyone else seen such a small amount of screw movement required to move from 250 to 340?

Will finish off idle synch, ride and report more later.

So grateful for this resource!
 
Ahhhhhhhh. Now I see the "just over 1/2 turn" in the Jim H post. Mine was also just over 1/2 turn to get that additional 100mv.

Maybe I should ask this question someplace else. This bike had been running with the Dobeck active. I deactivated it to set the idle as above. Did the motronic likely change its mapping based on the additional fuel the dobeck was adding? If so how long will it take to adjust to no dobeck? I'd like to see how the bike runs with no fuel assistance with the throttle plate where it is now.

MAN I forgot how fussy these are to get the cables in synch.
 
Last edited:
rkjjeep said:
Ahhhhhhhh. Now I see the "just over 1/2 turn" in the Jim H post. Mine was also just over 1/2 turn to get that additional 100mv.

Maybe I should ask this question someplace else. This bike had been running with the Dobeck active. I deactivated it to set the idle as above. Did the motronic likely change its mapping based on the additional fuel the dobeck was adding? If so how long will it take to adjust to no dobeck? I'd like to see how the bike runs with no fuel assistance with the throttle plate where it is now.
Click to expand...

Open up the fusebox and pull fuse #5 for ten minutes. This will reset the ECU and the learned fuel trims. The ECU will start learning again with the new setup.
 
rkjjeep said:
Ahhhhhhhh. Now I see the "just over 1/2 turn" in the Jim H post. Mine was also just over 1/2 turn to get that additional 100mv.

Maybe I should ask this question someplace else. This bike had been running with the Dobeck active. I deactivated it to set the idle as above. Did the motronic likely change its mapping based on the additional fuel the dobeck was adding? If so how long will it take to adjust to no dobeck? I'd like to see how the bike runs with no fuel assistance with the throttle plate where it is now.

MAN I forgot how fussy these are to get the cables in synch.
Click to expand...

There is no learning or map modification with the Dobeck connected. With the O2 disconnected the motor if can’t tell that the dobeck is adding fuel.

In order to learn/adapt you need a proper coding plug and an always connected O2 sensor.
 
Last edited:
Thanks Roger. When I received the bike it had the Dobeck 1033 that keeps the O2 sensor connected. Now I have reset the idle TB angle and the TPS to your recommendations and increased the cruise pot to (supposedly)deactivate the Dobeck. Went for a decent ride this morning. Great start, good cold and hot idle, great transitions when asking for more power. On an absolutely steady state light throttle it is obvious that the bike is trying to maintain forward motion as efficiently as possible. Feels lean in those situations but not quite a surge. I also noticed that set up like this the throttle is WAY less jerky snatchy off idle. Way better.
I could find no buzz, vibration or roughness anywhere. Runs like a bike with a closed loop fuel system trying to save fuel and meet emissions regulations, but silky smooth. When the XIED comes back in stock I will install and note the difference. I am not wild about the fact that the 1033 prevents closed loop. I like the stock closed loopedness and would just like to see what a little more fuel will do. Thanks.
 
Seems to be a lot more (almost too much) engine braking at closed throttle now. Still a good trade off for the other issues.
 
As stated in another thread I am really likng the AF-XIED. QUESTION: If the motronic is learning new fuel trims with the XIED installed does that all go away when we disconnect battery or pull fuse 5 for a bit? Thanks

I'll call beemer boneyard monday but I also have a question about the led patterns on the "gen 5" unit. I get the red light CONSTANT, the yellow flashes 7 times to confirm setting, and the green is on most of the time (occasional yellow). That's not quite what the new instructions say. Anybody else have a gen 5?
 
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