G'day have a 91 K1 , was wondering if there is a six speed BMW box that will fit this block?

Not as far as I know but if you find one do tell me.

Some of us wish there was one.....including me.

so K1200 motor and box is only way?

A K bike is not a Toyota Camry.  It is DESIGNED to run at the RPMs that it does.

And with a 33/12 final drive, a K1 already has the tallest rear end gear ratio of the classic K bikes.

I have often considered putting a 6 speed from a K1200 into an early brick but haven't so far been able to get a complete bell housing back for anything like a reasonable price.
Just looking at them side by side I don't think it would be a big engineering job but the reality may be a lot different. Its mainly the top shock mount and the rear mount on top of the gearbox that are different.
Mind the Bricks have a good spread of gears and heaps of torque and since I put some K1200RS cams in my K1100 it is heaps better.

I'm curious about the K12 cams in a K11. What cams? Straight swap?  What does "heaps better" mean?

The 1200RS cams are a straight swap for the 4v K1100 and put about 40° extra overlap on both sides.
The base circle is the same and so is the lift but the extra 40° is where the extra Neddies come from. I used the conventional  0.050in checking clearance and they come in about 35, 70, 75, 35.  I am not sure what the O'Fishal figures are but that's what I came up with.  My Idle is up a bit but I have yet to play with that and wont be doing anything like that for at least another 4 weeks (till the spine settles after the surgery)
I figure something like 20 HP extra with a slight drop in economy but I still got 4.6 lts/100 klms on my trip to the Kurauh Rally.
It was enough that when I was passing 2 cars at the last point before 16k of winding I kicked it back to 3rd and nailed it, It picked the front wheel up about 2 feet and carried it probably 25 metres. I was very surprised to say the least, I don't think it would do that by just rolling the throttle on as I really gave it some stick and dumped the clutch as I went into 3rd and I had quite a load over the back in panniers and top box.
The K1200RS bricks make 130HP so I don't think it is unreasonable to figure at least 120HP.
The K1200LT cams are the same as a K1100 RS/LT so be cautious what you buy if you intend to do the conversion.
The K1200 RS cams have 283° of overlap on the inlet and 286° on the exhaust which is fairly much the same as the euro K100.

Which parts are you comparing?

11311461691 & 3 are the stock intake & exhaust cams for both versions of the K1200RS.

Misunderstanding there, Yes I believe they are what I have I was told they came from a 99 model K1200RS. Apparently someone put a different set in his bike to tame it down because it frightened him.
Just spent some time on real OEM and I see the K1200LT cams are actually milder than the K1100 RS/LT but unfortunately it doesn't give all the info and lift could be more as I think the HP figures are very close.

Yeah, I'll bet the K1200LT cams are tame. Looks like BMW was still adhering to the voluntary 100 hp max like they did on the K1100s(and possibly K100RS4V/K1) 

I'll keep my eye on Fleabay for some inexpensive K1200RS cams and try them in my "spare" K1100RS.

BMW maintained low HP and high torque for the earlier K1200LT then in early 2004 bumped the HP from 100 to 116, and this was done through cam profile and ECU mods, we were told at the time. If you can see the donor bike the later cams came from, the additional highbeam headlight below the main is the giveaway. It was fitted to all K1200LT models, except those using Xenon headlights, from 2004 onwards.....in case anyone's looking for a midrange cam for their 16V.

 -o:


Now, what was that about a 6 speed...?

Initially I thought this was a made thread but now it looks very interesting indeed. I don't have a 4 valve but it does set one thinking of a 'stock' K100 with K1200 performance as in up from 90 to 120 neddies.