Help, can you remind me what this connector is and, more importantly, what it plugs into:



It's the 7-way, single row connector in the centre of the picture (5 pins used). It's in the main loom, down from the Motronics plug. Sits just above the gearbox, in front of the battery tray. That's the starter motor to its left.

I just wanted to run the bike up after fitting a new radiator, but before I do the clutch. Reconnected the bare minumum. Fuel pump works but no spark, so I'm guessing it's something ignition. But what? Don't remember unplugging this connector three months ago but it does look like it was plugged in somewhere. Can't find anything in the bottom of the boxes. What am I missing?

Ignition amp that mounts to the front left of the battery tray.  It's a good idea to take it off of the battery tray, clean things up and apply a new layer of heat sink compound between the back of it and the battery tray.

Ignition module only used on earlier Motronic through about late 1993.

Assumed it had to be something ignition. I'll go turn out those boxes again. Thanks.

12 14 1 461 441 is the OEM part number and a part of that number may be on the unit.

Look for these in your boxes.

As I recall it uses an earth strap as well.

Two Wheels Better wrote:As I recall it uses an earth strap as well.

The earth wire from the starter bolt goes to the battery tray.  (Brown wire in first pic.)

Pin 4 (Bosch 31) of the ignition amp connector is a ground so the brown wire is a redundant ground with respect to the ignition amp.

I could come up with some lame excuse about how I missed it 'cos it was all black with dirt - but I think it's more a case of not being able to see for looking, as my mother would have put it.  

Anyway, runs up, water stays in, one job done. Thanks everybody.

Next, pull the clutch off. Engine oil is dripping out of that hole at the front bottom of the gearbox where it meets the bell housing so it's safe to assume the clutch is soaked and needs replacing together with the crankshaft oil seal.

stanthomas wrote:Next, pull the clutch off. Engine oil is dripping out of that hole at the front bottom of the gearbox where it meets the bell housing so it's safe to assume the clutch is soaked and needs replacing together with the crankshaft oil seal.

No, it's not safe to assume that.  You'll need to pull the transmission off and inspect the clutch to see if it's been fouled.  It may not be fouled.

Two likely sources:

1 - Clutch nut O-ring

OR

2 - Output shaft seal

Once you pull the transmission off you should be able to tell the source of the leak and if the clutch is fouled.

duck wrote:No, it's not safe to assume that.  You'll need to pull the transmission off and inspect the clutch to see if it's been fouled.  It may not be fouled.

Duly noted. However, given that it is slipping badly my money has to be on an oily clutch. On the plus side, I might be lucky and get away with a friction plate alone.

On a slight tangent - at idle (1000 rpm) there's a horrible clatter coming from the back of the engine, or maybe the clutch area. Pretty much goes away at 2000rpm. Alternator is off. The idle is rough and a tune-up is definitely called for but is it normal for these bikes to clatter like they're full of nails when they're out of balance? Is there anything I should check while the transmission is off and have access to the back of the engine? It's a '91 16V with 85k miles.

Two Wheels Better wrote:Ignition module only used on earlier Motronic through about late 1993.

What has replaced Ignition module in later models?

It's my understanding that the ignition amp bumps up the voltage to the coils.  I think the next generation of Motronic puts out a higher voltage so that isn't necessary.

I believe this is when the change occurred between Motronic 2.1 and Motronic 2.2, just about 7th month of 1993 production on K1100RS as well as LT, according to www.realoem.com/bmw. 

When I built Big Block I initially used a 12/92 RS wiring loom for the engine, without an oxygen sensor. In order to tidy it up near the battery location I swapped the engine loom for a late 1994 RS loom, sans ignition amp, but with a Motronic 2.2 'brain' under the seat, and now with an O2 sensor screwed into the collector.

The 93 K1100 2.1 Motronic has both an ignition amp AND O2 sensor (at least for the US models that have a cat) but the ignition amp went away for the 94 model year with a 2.2 Motronic as noted above.

True dat, US models (and some other markets) did have cats with Mo 2.1....I just chose not to fit one until I had the '94 and later loom installed and the bung drilled and tapped for the O2 sensor.