Tricking out your K Motor. (Just for Fun!)

[Opus]

Okay here is the setup!
You have a extra K-Bike motor and the funds to trick it out to the 10's. I'm not talking BLING here now, but to really max out the power.
The only limit is that it has to be able to bolt to your frame. You can beef up the frame and other parts of the bike, but must retain the Org. look.
Oh and it must be a real and avalable upgrade, so no warp engines folks.

Let the BS begain!!!!! :loco:

[Rick G]

K 75 Pistons, K1100 throttle bodies remove the rev limiter of just go buy a K1200s and you get 40hp with no problems.

[frankenduck]

I recently hooked up with a local bike wrench who claimed he got a K75 from 74hp on a dyno to 93hp by decking the head.

[argent brick]

What is "Decking the head"?

[frankenduck]

What is "Decking the head"?

Machining down the face of the cylinder head. This creates a smaller compression chamber - thereby increasing your compression ratio.

[TimTyler]

[argent brick]

Sounds like what we called a "milled head".

[BuffaloRider]

I've also heard this called "alignment bored" and knew a guy who did it on a Gold Wing with tremendous results. Excellent power returns but also a really smooth running motor. I can see the advantage in doing a job like this on a motor like the Brick's.

[frankenduck]

I can see the advantage in doing a job like this on a motor like the Brick's.

Agreed. My K75 with a paralever needs a little more grunt coming out of turns.  I'm keeping my eye open for a low mile motor at a decent price to experiment with this.

[BuffaloRider]

The paralever conversion sounds interesting. How difficult was it and what all did you need to swap out?
If you are tearing down to do an alignment bore and head re-decking you may as well finish the job off right.

[frankenduck]

The paralever conversion sounds interesting. How difficult was it and what all did you need to swap out?

Converting a monolever K75 or K100 to a paralever final drive

[BuffaloRider]

So the entire operation is largely just replacing parts with similar units from later models?

[frankenduck]

So the entire operation is largely just replacing parts with similar units from later models?

Yup.

[wmax351]

One guy put a turbo on the K75. Got a bunch more power and torque.

Only has 55 hp stock at the wheel, so the 74 is at the crank.

A low pressure turbo is fairly tame on the motor. The only way to get significantly more power is to add forced induction, as the limiting factor is the air that goes past the valve. There is not a whole lot of power past the rev limiter on these bikes.

RBR turbos did some work on these when they were new. They pushed a K100 past 200 mph.

[WoahGold]

I saw one of those K100 turbos. I don't think I'd ever do it but it was interesting none the less.

I think having the block milled would be a great for the bike. I had the block from a 1947 Farmall B I was restoring sent away to be milled, reground, etc. and it made a huge difference.

[CrashBar]

What was different in the K1200 RS motor that it was rated at 130HP vs the K1100 at 100?

Thats a 30% bump on a 9% displacement increase.

Someone (duck?) did a swap, I wonder if it really felt like 30% more.

As I recall the K1200 LT was rated at the same HP but more torque.

[mystic red]

As I recall the K1200 LT was rated at the same HP but more torque.

And the K12LT weighs about 150# more

[frankenduck]

What was different in the K1200 RS motor that it was rated at 130HP vs the K1100 at 100?

Thats a 30% bump on a 9% displacement increase.

Someone (duck?) did a swap, I wonder if it really felt like 30% more.

As I recall the K1200 LT was rated at the same HP but more torque.

The K1100 Motronic is "de-tuned" to what at the time was a 100hp voluntary horsepower limit on the Euro bike market.