K75S to K75GS

I'm with this guy

But the practical side of me has to ask -- Why? I have an 1100GS now. I've never ridden a K75. Is there any inherent advantage? Lighter? Faster? More torque? Better handling? All of the above?

Lighter? No, they weigh virtually the same in stock config.

Faster? No, the GS is two mph faster on top.

More power? No. However, the GS only gets an additional 5hp from its extra 350 ccs.

Not surprisingly, the GS has quite a lot more torque.

The K75 has a slight edge in reported fuel economy, but not enough to make you fall over backwards. In my experience, however, the 75 will regularly return over 45 mpg.

The advantage here is that the K75 motor is jet-engine smooth, with a linear power band. It never seems to run out of breath, has plenty of grunt, and is very pleasant and relaxing to ride. Other than that, the suspension is old-school, and benefits from a fair amount of tweaking.

I think the big advantage here is that a K75 with low miles but crusty bodywork can be had for very reasonable money. The motor, tranny, and final drive are robust. Since the bodywork basically disappears, it's not an issue. The suspension gets a complete work-over. You end up with most of the capability of the bigger bike, a HUGE alternator for all your tecchy bits, and a total investment likely under a well-used GS. AND you get the cred of having a bike few have ever seen.

Thanks! Great info -- and the highlighted line says it all!

Heres the rear shock on my K100 sidecar. Shock is a Wilburs. Lifts the back end up about 2" at a guess. Drive shaft is modified to run in oil like the old R series BMWs. Extended breather stops water from getting in. Final drive is off a K75 for the lower ratio. And yes, it was muddy that day. Took it trail riding.

Quick Update;

Nearly 4000 miles on the conversion at this point. Updates include a small windscreen. Thanks to jdrocks for the idea. Also version 2 of the skidplate. The new engine protection is 1/4" ABS bent to provide a little better protection.

Impressions so far are very positive. It's no dirt bike, but at slower speeds it will handle most moderate 4wd roads and gravel ones are a hoot. The bike is incredibly smooth, comfortable and easy to ride. Suspension will get some more attention and changes in June.

Next trip is 740 miles to the Overland Expo in May. I'll try to get it off pavement on the way there and back.

MPG has been a bit of a surprise. With the high altitude plug in, I saw 57mpg last weekend. That's 7500 feet elevation and a fair bit of 45mph in 5th gear. Last week I dealt with the dreaded stuck starter relay. A new relay and battery solved the problem.

I like these lights, what are they?

The lights are Baja Designs dual 8". They were used on a desert racing bike that I had a few years ago. This seemed like as good place as any to use them again They sure can light up a dark road!

You could sell advertising space on that screen Why izzut screens these days have to be ugly upright awful loogin things? On some of those raid bikes you have to be standing all the time or looking out the side. Seems bikes are made to have a certain look rather than practicality. Sorry to be negative, I like what you've done to this bike. Cept the screen and mebe the lights...................................it's your bike, do wuthit watcha wanna doo.

Love your K....Well done!!!!!

I love this bike. Nice work.

Hi there Muddy3, I stumbled across your thread and hopefully you can enlighten me somewhat. I need to resolve the same issue that you have already done. Had my project bike for some time now but only started to look into the rear wheel issue earlier this year. Work is draining all my time at present but I need to push forward now. To keep the rear disc and drive from my k75 doner bike which rear wheel or hub will fit straight on with or without machining.?? I have read many many threads on this issue but it still leaves me spinning, which hub is on your bike..?? Could you also tell me what calliper and rotor were fitted by Woody etc..??
Thanks in advance, Mez/UK

Apologies for hijacking the thread on my first post, poor form I know

Hi Mez, .I am starting the same conversion, but its early days yet. I have gone for GS1150 rear wheel, looks a little wide and there could be problems with the caliper hitting the spokes. I will have a little play this weekend.

I also have some DRZ 400 front forks, and going to look at a K1100 paralever final drive set up tomorrow night, that is in a poor state.

I will start a thread on SAR, when I'm ready.

Mike

Hi Mike, I've just bid on a 1150 rear wheel so fingers crossed...!!! I had an email back from Zach at woody's wheels and the 1150 wheel will fit with some machining etc... the 1150 disc, calliper and carrier has to be used also. The rim will have to be relaced and offset or the wheel itself spaced. Would be great to share a thread with you mate for comparisons etc etc... Keep me upto date ok..

Mez

That bike looks really great! How are you liking the Shivers?

Sorry guys for the slow reply. I've been out of town shooting speed goats in Wyo. for the last week.

flipflopdog has it exactly correct...the parts are all 1150 with the wheel re-laced w/ offset.

The Shiver forks are fine although I've gone with KYB forks from a YZ450F reworked by RG3 for my next project. The new project is a fleebay/homebuilt version of a HPN boxer. Rolling chassis is done, need engine and 11 gallon HPN tank...photos to follow!

Here you go:



...and with the adapter to make the forks/triples fit.

Nice build!

Can you tell us what you did for a seat?

I looked at the Baja Designs Driving lights thinking I could do 1 for a more traditional look,.............but...........looks like these do not come in a dual filament HI/LO configuration. Wondering if that kind of a bulb/socket could be fitted?

Brian in Austin

Yes, Boatman does a conversion ring. Here's the result.