LocostUSA.com

I searched but didn’t find anyone who has used the BMW K1200RS engine and transmission in a build. I have a complete 1999/2000 set-up here at the shop which has the full wiring harness, handlebar switches, clutch and brake master cylinders, dash/gauges, radiators, exhaust and more. It makes 120hp and 90ft-lbs torque, so it’s comparable to some other small displacement automotive based motor. It’s quite compact, but since it is laid over sideways, it’s a bit wide. That might not be a problem in 7-type chassis since the engine compartment is on the wider side. If one could make the combo fit, the center of gravity would be very, very low!

Hopefully someone here has played around with this engine/transmission combination and has some info to share with the group.

_________________
Dan Lipperini Jr
www.RaceLabz.com

Dan, what direction does the driveshaft shaft turn? I have a suspicion you will end up with 6 reverse and one forward gear.

Graham

I’ll have to do a bit of research. If it isn’t useable, I guess I’ll be looking to build that reverse trike that I’ve been looking at.

_________________
Dan Lipperini Jr
www.RaceLabz.com

The interwebs state that the engine rotates clockwise as viewed from the front(clutch rotates ccw as viewed from the rear). I have a few Ranger rears at the shop and will check later today. Fingers crossed!

_________________
Dan Lipperini Jr
www.RaceLabz.com

What side does the drive shaft run down the swinging arm? I think that will tell you. I think if it runs down the left side as you sit on the bike your OK. Look at the Triumph Rocket 3 and the Honda Gold Wing. You can always put the diff/axle in upside down, oiling can then be a problem.

Graham

All BMW’s run down the right side as seated on the bike.

_________________
Dan Lipperini Jr
www.RaceLabz.com

If it is going the wrong direction, and you don't want to flip your ranger axle, you could use an IFS front diff from something like a 4runner.

These motors are cool, and last forever, I hope to see you tackle this build.

_________________
Cheers,
Logan

If you look up "carsandcameras" on YouTube you'll find a build they did with a K-series flat four engine...
I think they had to flip the rear axle indicating that the rotation was wrong...

Edit: did the search: https://youtu.be/YWy5sqmkt4M?si=lcEjjFDN5QUX1PAZ

I guess you could use a reverse gearbox with 1:1 ratio so it would technically be running in reverse and then when you want to go in reverse you change to forward. I don't know if it would effect the lifespan of the gearbox. I'm curious if there is a way to change out the gears to a modified Lt to get the Lt 5 speed reverse to work mechanical instead of using it with the starter? That would mean the axle would need to be flipped though.

I want to drop the k1200rs into my opel gt rebuild. Im wondering if the Lt 5 speed transmission could be adapted to use the reverse gear for the starter to be used as a normal mechanical reverse. Other option is to use a 1:1 reverse box behind it to use reverses forward and forward as reverse but I don't know if it would end up wearing out quicker.

Hi I'm hoping one of you was able to figure out if the motor and transmission rotate the correct way? I believe it's CCW from the rear of the motor that I believe is correct for normal cars? If not, has anyone checked if the transmission rotates it in the opposite direction so the counter rotation to balance the motor and transmission so it wouldn't pull the bike to the right when laying on the throttle?

I'm hoping if it is rotating the wrong way, I could change out the transmission to a car transmission to fix the rotation and get a reverse gear in the process.

I was originally looking for a more powerful motor but this one would save so much weight that I thing the power to weight would balance out what I was thinking for a 250hp 1800lbs setup. Having 200kg less would mean a 20php setup would end up much better.

Thank you to everyone that has done the research and has the experience to make my basic build easier using your initial testing. I wouldn't be able to do this without you.