2001 R1100 RL, 5200 miles (new owner). Bike sat for 12 years, with gas in the tank, and wasn’t running when I purchased it. Replaced fuel delivery system, fluids changed, new tires, relined fuel tank and a few other things. Since getting the bike running, I’ve rode it 200 miles and recently synced the throttle bodies. No issues until this past weekend. A friend was giving it a test ride and advised he almost crashed when down shifting at about 35-45 mph coming to a stop. He explained he was traveling about 70 mph when he noticed the car in front of him braking. He reduced speed and began downshifting. He doesn’t recall the gear he was in but at approximately 40 mph the MC cut completely off and the rear tire locked up and the bike slid until he pulled in the clutch at which time the rear tire unlocked and rolled. While continuing to hold in the clutch he pressed the start button and it cranked with no problem. What the heck happened. Can these bikes lock up like that even when you are traveling within the appropriate gear range?
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While downshifting the bike cutoff and rear tire locked up
- Thread starter eleven
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m_stock10506
Well-known member
Sounds much more like the motor stalled while he was coming down from 70 to 0. He may have also dropped into a lower gear than intended too soon and that could easily lock up the rear wheel. A gearbox lockup of the rear wheel (it's not really locked up, just not turning enough) won't be fixed by the ABS system.
Sounds mostly like operator error, but I would check the idle. Make sure it is smooth and make it about 1100 rpm. Check the Big Brass Screws on both throttle bodies, that they are clean and the passages are clean.
Sounds mostly like operator error, but I would check the idle. Make sure it is smooth and make it about 1100 rpm. Check the Big Brass Screws on both throttle bodies, that they are clean and the passages are clean.
pauls1150
MOA #24991, south of Los Angeles
While all of the above is true, it may also be worthwhile to somehow confirm whether or not "the MC cut completely off".
That sounds electrical; based on the initial post, I'd suggest examining the tank's connector (right side, below and to rear of tank), various "safety" switches (kill switch, sidestand switch, clutch switch, even the main ignition [keyed] switch) and the wiring on both sides of the round "fuel plate" in the tank. If the fuel pump cuts off, the bike dies...
Does this bike have the RID (Rider Information Display: clock, gas, temp)? If so, ask your friend if he noticed if that changed or reset, tho he may have been too busy at the time...
That sounds electrical; based on the initial post, I'd suggest examining the tank's connector (right side, below and to rear of tank), various "safety" switches (kill switch, sidestand switch, clutch switch, even the main ignition [keyed] switch) and the wiring on both sides of the round "fuel plate" in the tank. If the fuel pump cuts off, the bike dies...
Does this bike have the RID (Rider Information Display: clock, gas, temp)? If so, ask your friend if he noticed if that changed or reset, tho he may have been too busy at the time...
Appreciate everyone’s replies to this thread. The bike did cut off completely. He noticed a few of the circular lights come on, probably oil and battery light, and coasted several feet with the clutch in before pressing the starter button and restarting the bike. The display consists of an analog clock and circular lights for oil, battery, turn signals, etc...but no temp light. Thanks again.
I couldn’t figure out the issue after it happened a second time so I took it to a BMW mechanic. He reported it was way out of sync and he did the zero=zero procedure. I had the big brass screws turned out too far. I was surprised that being out of sync could cause the bike to cut off while downshifting. Why would it not cut off every time the clutch was pulled in vs only when downshifting? Thanks again for all the help/information provided regarding this issue.
pauls1150
MOA #24991, south of Los Angeles
Only speculating from afar, but... Having the BBS (idle air) screws too far out allows more air to the fuel mix, and downshifting creates higher intake vacuum. This plus being way out of sync may have resulted in a condition (too lean) that the computer could not compensate for.
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jsouth
Member
The good news is, you are on the right path. The bad news is, if he truly did zero=zero, that is really old information, and not the recommended procedure now.
The new gold standard is zero=250mV. See this link by roger 04 rt, who has done incredible research and debugging:
https://forums.bmwmoa.org/showthrea...nd-Zero-Zero&p=1091142&viewfull=1#post1091142
Thanks for the reference. First time I’ve heard about the zero=250mV. I’ll definitely ask about that next time our maybe try it myself.
jsouth
Member
You are very welcome. Roger is a BMW oilhead EFI legend. He is still a current member and I have found him to be not only super knowledgeable, but also willing to help when you get stuck. You're not far from where it should be at zero=zero, but it will run better at zero=250mV or 270mV!
I bet it will. I’m amazed at how well it rides now compared to before. A lot smoother. Just surprised it would cut off like it did because of a sync issue. I synced the TBs using a Carb Pro II but then agin it was my first time doing that. A lot of knowledge and experience on this site.
pauls1150
MOA #24991, south of Los Angeles
Be advised that if you change the throttle zero to 250 mV at the TPS, you'll need to "re-initialize" the "Basic" throttle settings for the computer: key on but engine not running, slowly twist the throttle through its full range three times, and turn the key off. This creates an initial starting point for the computer.
Also, it will take several rides (or one long one with all varying conditions) for the computer to learn and re-program the new real-world fuel/ignition mapping, so don't get upset if the "first" ride isn't quite what you expected.
With apologies to Roger, definitely one of the Good Guys, there is still some disagreement as to whether the 250 mV setting actually makes any real-world difference. The spec from Bosch is clear in that they say a "Zero" should be 250 mV.
I set mine - and a couple of friends' bikes - to zero volts (actually about 5 mV, since below that, the wiper of the pot just falls off of the resistive element) per Rob Lentini's guide, long before we found out about the Bosch spec. After the computer self-adjusted (decided on what to program into its memory), they all ran just fine. I haven't seen the others for a while (at least two are now out of the state), but my bike runs GREAT (of course I'm a little biased there).
The difference is that due to the offset - which the computer will eventually load into its bank of memory addresses - the map just gets loaded into different addresses. So what.
I don't want to pull this off-topic with another TPS discussion, I just wanted to make you aware...
Paul S
Also, it will take several rides (or one long one with all varying conditions) for the computer to learn and re-program the new real-world fuel/ignition mapping, so don't get upset if the "first" ride isn't quite what you expected.
With apologies to Roger, definitely one of the Good Guys, there is still some disagreement as to whether the 250 mV setting actually makes any real-world difference. The spec from Bosch is clear in that they say a "Zero" should be 250 mV.
I set mine - and a couple of friends' bikes - to zero volts (actually about 5 mV, since below that, the wiper of the pot just falls off of the resistive element) per Rob Lentini's guide, long before we found out about the Bosch spec. After the computer self-adjusted (decided on what to program into its memory), they all ran just fine. I haven't seen the others for a while (at least two are now out of the state), but my bike runs GREAT (of course I'm a little biased there).
The difference is that due to the offset - which the computer will eventually load into its bank of memory addresses - the map just gets loaded into different addresses. So what.
I don't want to pull this off-topic with another TPS discussion, I just wanted to make you aware...
Paul S
Thanks Paul S. Appreciate the details regarding the Zero procedure. Good information.
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