Hey all
In addition to my 1985 K100RT, i've got myself a K100 / 2 - Model, DEC 1997 vin decoded production date. Bike was sitting for the last 6 years but after cleaning the injectors and replacing the battery started and idled like a champ with just two turns of the starter motor. 10.000 km only on the engine. Problem is that has no registration papers since the owned had died and his kids declined the heritage due to their personal reasons.
Tank has a minor pine size hole underneath so its leaking and the fuel sender is a block of solid heavy corrosion. 
Anyway, I m seriously thinking of swapping my 110.000 km  current engine with the new one. 
Problem is I cannot find info about this K100/2 specific model regarding final drive transmission ratios etc.

So, to the point. 

1. Is engine swap a direct swap? I mean complete with gear box and final drive, arm, etc?
2. In a first inspection I noticed that a plastic flat "tray" underneath the wiring loom under the tank is missing. Is this normal for this model? 
3. Are there any differences between two bikes in terms of FI computer under the seat and the ECU or they are identical directly swappable? 
4. Are the footrests compatible for mounting on the same holes? Are there differences in height of the drivers footpegs height between these two models? 

 I would really like your thoughts on this swap. My current running old engine is fully reconditioned with 4 hole new injectors , valve clearance set, Tb's tuned, clutch assembly new, Gearbox, Clutch, seals and RMS replaced, Oil/water pump rebuilt, new Bosch Fuel Pump, splines properly lubed and in great shape. 

Thank you!

Please post some photos, George. The description of this model is too vague. Post the actual VIN decoder description.

That helps. In your opening post you stated it is a 1997 model but it is actually a 1987 model. Swapping the engine and other parts should be possible. Your 1987 model is a low-seat model. The seat is closer to the pavement. The low seat configuration leaves no room for the tool box that was a part of the standard seat model.

Closer observation should determine whether foot peg mounting plates align identically. There doesn't seem to be a difference reflected in the Max BMW parts fiche.

If your old engine is reconditioned and running well and your old moto's fuel tank is ok, what is it you want to swap? You might be able to move the low-seat onto your current moto, if you want firmer footing on the pavement. It seems to me you've either just bought a lot of spare parts with less mileage on them—if they are its original parts, or you've just contracted K-pox. 

Hi George,
I also have a K100/2. Mine was built 11/87, I'd say yours is a 12/1987 build. The main differences over the same age RS/RT/LT are that the K100/2 has the 21litre tank used on the base K75, and a low seat as standard. The low seat means you don't have the tool under the seat. 

Engine and gearbox and wheels are finished in black with unpainted highlights, but otherwise the same as the RS/RT/LT of that age. Final drive ratio stamped on the casing on mine is 32/11 (2.91:1). I think that's standard. The ECU and FI computer are standard K100 2 valve.

I've been through the corroded fuel level sender replacement. Mine had corroded enough to stop the 12Volt feed to the fuel pump.

Below is a link to the model year 1988 press release, it has a bit of information on the updated basic. Hope you get it back on the road - they're a bit of a rarity in the K100 world.

http://forum.kforum-tech.com/members-upload/uploads/1988_Press_Release.pdf

Regards,
Richard.

Basic2 wrote:
I've been through the corroded fuel level sender replacement. Mine had corroded enough to stop the 12Volt feed to the fuel pump.

Below is a link to the model year 1988 press release, it has a bit of information on the updated basic. Hope you get it back on the road - they're a bit of a rarity in the K100 world.

http://forum.kforum-tech.com/members-upload/uploads/1988_Press_Release.pdf

Regards,
Richard.

Its a really nice looking classy K Richard! Unfortunately there is no chance to get it back on the street as is due to permanent de-regisrtation. I would really love to though.
I can find a sender new from Motobins for about 140-160. 
Since you have the same model can you please verify if there is a plastic tray separating the wiring loom connectors from air boxes under the tank? 
Thanks for the link too!

I think I'm in agreement here. The K100/2 is rare enough for you to perhaps consider putting it back on the road.

Is there no way that the Greek authorities can issue duplicate paperwork? It's not a problem here if you buy a bike that has no registration docs - you just apply for a new set. The authorities check that the bike isn't noted as stolen and send you the papers.

George_Pap wrote:

Basic2 wrote:
I've been through the corroded fuel level sender replacement. Mine had corroded enough to stop the 12Volt feed to the fuel pump.

Below is a link to the model year 1988 press release, it has a bit of information on the updated basic. Hope you get it back on the road - they're a bit of a rarity in the K100 world.

http://forum.kforum-tech.com/members-upload/uploads/1988_Press_Release.pdf

Regards,
Richard.

Its a really nice looking classy K Richard! Unfortunately there is no chance to get it back on the street as is due to permanent de-regisrtation. I would really love to though.
I can find a sender new from Motobins for about 140-160. 
Since you have the same model can you please verify if there is a plastic tray separating the wiring loom connectors from air boxes under the tank? 
Thanks for the link too!

I'll take some photos tomorrow.

Dai wrote:I think I'm in agreement here. The K100/2 is rare enough for you to perhaps consider putting it back on the road.

Is there no way that the Greek authorities can issue duplicate paperwork? It's not a problem here if you buy a bike that has no registration docs - you just apply for a new set. The authorities check that the bike isn't noted as stolen and send you the papers.

Would really love to put it back on the road. Unfortunately the laws here are more rusted than the fuel sender. 
The only way to put it back to road is the issue of special -classic antique- permit with special number plates that you can use only in special events, Antique rally, exhibitions , etc.

Basic2 wrote:I'll take some photos tomorrow.

I don't want to put you into trouble with photos, etc. Richard
I just want to know if that part should be there. 
Thank you!

George_Pap wrote:I just want to know if that part should be there. 

If this is the part you want like the one under your 1985, it isn't in the low seat model k100/2 because there is no room for it under a low seat.


If you're look for a relay box that has relays inside it and fuses on the outside like in your 1985, it should have one—like this.

Nope mate. 
I mean a flat plastic tray as shown on the photo with the yellow outlining. 
Its just a photo I found one the net and I have just outlined the "shape" and position of that tray.

The part number for that is 46632309169 - Cover. I think it's there to mitigate heat exposure on the bottom of the tank. Whether or not it accomplishes that to any significant degree is probably up for debate.

Only the 4 cylinder Ks and K75RT models have that. The other K75s don't.

I don't think it will be the end of the world if you don't have it.

A couple of photos of under the tank on my K100/2 - there's no cover.

The standard K100s didn't have it.  Only the faired bikes - RS, RT & LT.

Thank you so much !

duck wrote:The standard K100s didn't have it.  Only the faired bikes - RS, RT & LT.

Thank you!

Ah! that explains a lot. I once tried to use a technique I read on here about unscrewing the clamp on the hose from the airbox to plenum by coming at it from above. Couldn’t find any way of doing it with that plastic sheet in the way...

Im not sure if  this helps. I did an engine swap on an 86 K100 with an 87 K100 I understand they were basically the same generation and model, but  it was incredibly simple. It was literally four bolts. The hardest part was un-hooking wires and cables... but easy enough. I just put a jack under the engine undid the bolts and  rolled the frame off the engine, gear box and final drive/rear wheel. Then rolled it to the "new engine" and  kept the  new engine ECU and wiring harness. I connected the clutch cable and throttle cables and  put the bolts in. It was literally  less than a 2 hour job. If the  mounting bolts are in the same place on both bikes I don't see why it would be any different. If they are not in the same place then it becomes a big deal. 

This is what the engine/transmission and final drive looked like minus the frame:

The  frame is what carries the VIN (At least in USA) so  no need to hassle with registration since the bike is registered by the Frame # (It may be different in other countries)

That seems like more of a drive train swap than an engine swap.  Swapping just the engine is a tad more complicated.

thank you all gentlemen