Given that I hold the BMW Special tools for the BMW Club UK, in the past I have though of getting hold of 'standy' parts, like ECUs, to send out to our Club Members who may be in a similar position as the Kaptain. The only drawback would be where a bike fault fries the ECU. If that occurred, my 'loaner' would be short lived. 

Only yesterday I stripped and rebuilt a rear drive from a 1200GS (Main bearing failure) for a club member. Today, at a Club meeting, I discussed the option of having a standby (rebuilt) unit, that could get someone back on the road promptly, allowing them to sort out their own drive in a more leisurely timeframe.

I may look at this in more detail.

P.S. 2 x bearings, 2 x oil seals. 1 x casing 'O' ring 10 x casing bolts and three crush washers was just over £130

Mike

If anyone would like to try my faulty ecu to prove the fault just let me know.
However in the short term I'll be investigating a couple of avenues for finding a repair solution for this ecu. If initial feedback is not favourable then I'll look for a replacement asap.

Glad to hear the ECU solved your problems. I fitted a new HP pump and the follow on filter, and its running much better. Its not cutting out on the downchange now, but it still has a an occassional hiccup at around 5000 rpm. When its fully up to temperature, 85 degrees plus, the tick over climbs from 950 to 1400. The heatwrap is still smoking after a run, but I think this is down to an oil leak hitting the wrap, and then it burning off.
Wizzard

Hi wizzard
There are similarities but it seems that there are also a lot of dissimilarities. I suspect you have multiple issues happening that may be interacting with each other.
Would be best to start a separate thread for your problem clearly restating your symptoms again.

Cheers

I agree KH - the problems have similarities, but different causes. It seems to discover new faults on a regular basis. I'm almost at the stage of buying a good running bike for spares.
Wizzard

wizzard wrote: . . . I'm almost at the stage of buying a good running bike for spares.

I did this and was lucky to get a machine with only 48000 ks on it for 2 grand. I am so glad I decided to get it. I actually bought number 2 for the engine but it has been an invaluable source of hard to get parts and completed all the bits I needed to restore mine to orginal status. Things like seat rubbers, footpeg rubbers, certain bolts and wiring etc that had been tampered with before I got hold of my bike

I managed to buy quite a few spares at a good price on a french internet, which hopefully means I dont have to buy a donor bike. Another reason I didnt want to buy a bike just yet is that after I get the Grinnall french registered I intend to fit a K1200RS engine for a bit more power. IF I can get it registered - France is probably the hardest country in the world to get an oddity registered.
Wizzard

Here we go again. The problem where the engine died on the change down seems to have been resolved now, but now the problem of the engine dieing sometimes at 4500 to 5000 revs is getting worse. It feels like the engine is running out of petrol, but it doesnt die totally - on dipping the clutch the engine goes back to tickover. I'm really pulling my hair out with these problems - I keep replacing parts to fix one problem then another surfaces or gets worse.
One clue which may help ring a bell with someone is that this fault does not occur until the temperature gets up to 80+.
This week the injectors are coming out and new seals fitted. If that doesnt help, then I will try the fuel regulator.
Any other suggestions would be welcome - fuel pump , filters, ECU, ICU, and lots more bits have already been changed.
Wizzard

Have you checked valve clearances?  The fact it needs to be warm may be related to these clearances.

Well, I spoke too soon, the cutting out at junctions started again.
So today, I fitted -
a) a replacement wiring loom covering the ECU and associated sensors, etc
b) ICU
c) TPS
d) Fuel regulator

that lot didnt make any difference, so

I fitted a replacement set of throttle bodies.

It ran beautifully, ticked over perfectly and sounded soooo sweet, then ...

It died and wouldnt start again .  I left it for a while , then it started again, then died again. I gave up and went out to thrash the Harley for a few hours. Then , when I came home the da*mn thing started again and ran perfectly.
I've no idea how to resolve this , and I cant trust it to get me home without breaking down.

Wizzard

Is one of the items that you have changed been the Hall Effect sensor assembly?  I didn't suggest this at first since you mentioned much of the electrical has been replaced.  The symptoms are similar to a defective Hall Effect sensor.  The engine won't run unless it gets a reliable signal from this part; and these tend to exhibit failure moreover when the engine warms.

robmack wrote:Is one of the items that you have changed been the Hall Effect sensor assembly?  I didn't suggest this at first since you mentioned much of the electrical has been replaced.  The symptoms are similar to a defective Hall Effect sensor.  The engine won't run unless it gets a reliable signal from this part; and these tend to exhibit failure moreover when the engine warms.

I too would be looking here.

I remember when I had issues getting my rebuild going one of the things I did was swap out the hall effect transmitter. That isolated the problem to a broken injector wiring in the loom. I have red somewhere that the circuit  is a closed circuit.

Meaning that ALL of the cylinders have to fire for any of them to fire.

I may be wrong but what have you got to lose by testing the theory at this stage of the investigation

Hope this helps you somehow

Be made wrote:

robmack wrote:Is one of the items that you have changed been the Hall Effect sensor assembly?  I didn't suggest this at first since you mentioned much of the electrical has been replaced.  The symptoms are similar to a defective Hall Effect sensor.  The engine won't run unless it gets a reliable signal from this part; and these tend to exhibit failure moreover when the engine warms.

I too would be looking here.

I remember when I had issues getting my rebuild going one of the things I did was swap out the hall effect transmitter. That isolated the problem to a broken injector wiring in the loom. I have red somewhere that the circuit  is a closed circuit.

Meaning that ALL of the cylinders have to fire for any of them to fire.

I may be wrong but what have you got to lose by testing the theory at this stage of the investigation

Hope this helps you somehow

Not at all, one of the sensors works #1 & #4 and the other #2 & #3. However on a K75 if one fails it only runs on one cylinder because there are only 2 sensors for 3 cylinders and the #2 cylinder firing is worked out by the computer (ICU) when to fire it by the position of the other 2.

Be made wrote:Meaning that ALL of the cylinders have to fire for any of them to fire.

I think you may be getting confused with the fuel injectors. They all fire at once, so each cylinder gets three squirts before it finally gets sucked in. Can't figure that one out...

Dai wrote:

Be made wrote:Meaning that ALL of the cylinders have to fire for any of them to fire.

I think you may be getting confused with the fuel injectors. They all fire at once, so each cylinder gets three squirts before it finally gets sucked in. Can't figure that one out...

Yep. Probably. my bad

I've been putting off changing the Hall sensor (I've got a spare one) for one major reason - the trike has a spaceframe chassis, and to access the Hall sensor the engine has got to be removed! I read somewhere about testing it with a hair drier - would this work with the casing still on? Would the engine running statically for just a few minutes get warm enough to trigger the fault in the sensor? 
Sorry about all the questions but this simple job will entail some major work - to be avoided at all costs.
Wizzard

I don't believe you can simulate the error with the cover on; the sensor array won't get hot enough because the case and engine will act as a heatsink.

Well, the story continues.... but there is a very happy ending.
Just to quickly recap, as per orig post, 4000+ rpm, throttle off, clutch lever in >>> engines dies. Has led to a few sticky situations in traffic.
While I could replicate the problem, it was vaguely intermittent.
Other symptoms I had at the time included backfiring plus high and eratic fuel consumption although I did not link these to the original problem of engine failure at the time.

Much advice and many suggestions like earth contacts, battery, ECU, TPS, valve clearances etc etc
ECU seemed the most logical and easy to do so I swapped this out with a known unit and the problem appeared to disappear as discussed just above and I found a replacement unit online. However a few weeks latter and the engine dies again... and again. It had a lot to do with the riding style and the traffic situation at the time.

Another suggestion, thanks to robmack, who had read about something similar on a MottoGuzzi forum, suggested it could be the exhaust valve clearances. After reading that info myself I was very hopeful. A check of the clearances revealed exhaust 1,2 & 3 were very tight (read my thread here). Had to order the special tools from the US, measure up, order shims and replace. Took me a while to get all that together and with a busy time leading up to Xmas I didn't get around to finishing the job till early Dec last. First ride told a nice story. Very noticeable increase in power, better idle, revved out far more easily, a lot smoother and no back firing. Also, I could not get the engine to die. Early days tho so I didn't get my hopes up.

I've been away for four weeks over Xmas/NY and after racking up 2500 klms with quite a bit of city/town riding where 'the problem' is most likely to occur, I'm pretty confident I've now seen the last of that curse. Not even a suggestion that the engine might die under any condition.

Another big plus (which I've mentioned in a couple of other posts recently) is that my fuel consumption has gone from a very eratic 6.5 to 8 lit/100km down to a respectable and constant 5.6

The eratic fuel consumption has led me to think (rightly or wrongly, I have no idea) that at times the engine was running reasonably well and was not inclined to die and at other times not so well and was more inclined to die, hence the vaguely intermittent nature of the symptom.

So anyway, I'd really like to thank everyone for their contributions and to those who gave me assistance and of course to robmack.
 
Its been a frustrating but very interesting ride.
Cheers

Well guys, I have replaced everything that can be replaced (except the Hall sensor), and the problem still appears occasionaly - the stuttering (always between 4000 and 5000 revs, when its warm). The problem with it dieing out on the downchange is "controlled" by leaving the starter out a fraction. Again, this is not a consistent problem - sometimes it will not cut out for 2 or 3 trips, then it suddenly starts again. Its so frustrating I've just bought aa low mileage K100RT to use for spares. I'll change the engine if I have to, but sods law says the problem will still be there!
Wizzard

Did you get around to checking your valve clearances?

wizzard wrote:Well guys, I have replaced everything that can be replaced (except the Hall sensor), and the problem still appears occasionaly - the stuttering (always between 4000 and 5000 revs, when its warm). The problem with it dieing out on the downchange is "controlled" by leaving the starter out a fraction. Again, this is not a consistent problem - sometimes it will not cut out for 2 or 3 trips, then it suddenly starts again. Its so frustrating I've just bought aa low mileage K100RT to use for spares. I'll change the engine if I have to, but sods law says the problem will still be there!
Wizzard

could this be a sign of the afm going open circuit on the contact points of the armature and pinion of the sweep arm ....so might be at revs because of the open circuit condition   to the injection computer ...it is actually at idling measurements  ...or even worse nothing value ....crikey the computer must be confused ...but the "richen signal " (from pressing the start button ) takes precedence ?

I have personally found at least 2 with this issue  , and successfully fixed 1 to date

it is a known issue with all lejetronic systems across all manufacturers ....bmw upgraded some of the later series of afms with a cable between the 2 connections points

this is the connection point im referring to   open it up and play with it  to see if it goes open across its action and also if it has some movement in the assembly ...turn it upside down etc  whilst moving the barn door open and closed ..

a multi meter across both points would be a recommendation

Hi Guys
1) I havent checked the valve clearances for a couple of reasons a) it means taking the inverted saddle fuel tank out of the trike, which is actually a pain in the ass job  b) logic would say that if it was valve clearances at fault it would happen predictably, rather at random and well spaced conditions. Opening the starter wouldnt make any difference to valve clearances. The previous owner said that he didnt have this problem (he is a friend and would have no reason to lie about it long after I bought it), but it was hardly used during his 10 years of ownership.
2) By AFM do you mean the TPS? I have changed every sensor, ECU, coils, ICU, fuel pump, filters (there were 4, now just 3), including the TPS,but excluding the Hall sensor due to the access problems. Some of these parts I've changed more than once.
Its interesting how everyone who has this brief fuel starvation problem says it kicks in between 4000 and 5000 rpm. There must be an experienced BMW mechanic who has come up against this roblem dozens of times and knows exactly what causes it.
Wizzard

"2) By AFM do you mean the TPS?"

AFM = Air flow meter...........inside the air filter housing.

Thanks for clarifying that - I had no idea how to check the AFM. I picked up a low mileage K100 today - mainly to put the engine into the Scorpion, but I will try changing the air filter/AFM first.
Cheers, Graham