BMW K1200S; nice donor?
Mave - 20/12/04 at 04:46 PM
I was just browsing through some motorcycle mag, and came across a technical article about the BMW K1200S.
It seems like a very interesting donor: 167 bhp, 130 Nm, 81,9 kg (including 'box), propshaft, comes with dry-sump, very low due to angle of
cylinders (55 degree).
Oh, and for LHD cars; the engine is largely on the right hand side of the car!
Might be a bit expensive now, but maybe it makes for an interesting donor in two years?!?
phelpsa - 20/12/04 at 04:55 PM
My dad is thinking of getting one of these.
Smooth Torquer - 20/12/04 at 05:29 PM
Hi there,
I was going to use a K100 engine as my donor but once all the fairings were off and we could measure it, we discovered that it would be very tight in
my (book) chassis.
And due to the shape on the back of the gearbox it would need a wider transmission tunnel to fit.
The K1200 might fit better, but I think that BMW haven’t really changed the external dimensions very much.
The other difficulty we encountered was its hard to find a diff with the right kind of ratio.
Get in touch with the guys at ADR, they use K engines in their cars, and were helpful when I spoke to them.
ADR link
Hope this helps
Sam 
CooperLight - 20/12/04 at 07:49 PM
great tourque numbers ! and drysumped .
Smooth Torquer: what do you mean with "hard to find a diff with the right kind of ratio"
How is it different to other engines R1, blade etc ?
.
zilspeed - 20/12/04 at 09:36 PM
quote:
Originally posted by CooperLight
great tourque numbers ! and drysumped .
Smooth Torquer: what do you mean with "hard to find a diff with the right kind of ratio"
How is it different to other engines R1, blade etc ?
.
I'll butt in here if I may.
R1 and blade engines rev to eleventeen zillion RPM and so the whole drivetrain cna live with a car diff and still have a sensible top speed.
The BMW will have a good 2-3000 lower red line and a consequently lower top speed.
It may not make much difference around the lanes, but on a track, you could find yourself running out of revs half way up the main straight.
phelpsa - 20/12/04 at 09:56 PM
Red lines at 10000rpm
Most screaming bike engines have a primary reduction of about 1.5:1, which increases torque and decreases rpm.
Adam
Smooth Torquer - 21/12/04 at 01:00 AM
CooperLight I was saying that it was an issue when using the K100 engine, as I was going to. The K100 engine revs to 8500, lower than R1 and Blade
engines.
iirc the gear ratios in its box are quite different to jap bikes, and so to get any sensible top end speed for comfortable road or track use a diff
ratio of about 2.7:1 would be needed.
Sam