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Discussion Starter · #1 ·
Anybody know what the difference is between the ESA fork legs and lower triple clamp between the R and the RS?

Looking at pictures I cannot see any difference what so ever, but the part numbers are different:

Left leg:
R = 31428533867.
RS = 31428555697.

Right leg:
R = 31428533866.
RS = 31428555698.

Lower triple clamp:
R = 31428550142.
RS = 31428550145.

Reason for asking is that I'v been looking for used parts for the R1200R but have not been able to find any good ones really, but I have found two sets for the RS though. :rolleyes:

Reason for looking in the first place is that I'm building a bike that could closest be described as a K1600R and I've used R1200R parts that I've borrowed from an R1200R that is beeing put back together now.
 

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Anybody know what the difference is between the ESA fork legs and lower triple clamp between the R and the RS?

Looking at pictures I cannot see any difference what so ever, but the part numbers are different:

Left leg:
R = 31428533867.
RS = 31428555697.

Right leg:
R = 31428533866.
RS = 31428555698.

Lower triple clamp:
R = 31428550142.
RS = 31428550145.

Reason for asking is that I'v been looking for used parts for the R1200R but have not been able to find any good ones really, but I have found two sets for the RS though. :rolleyes:

Reason for looking in the first place is that I'm building a bike that could closest be described as a K1600R and I've used R1200R parts that I've borrowed from an R1200R that is beeing put back together now.
I can't answer your question, but I'd like to see a photo of your project bike!
 

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2020 R1250R HP
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It's about time someone built a K1600R since the lazy Germans didn't bother. I believe RS legs are slightly longer due to the slightest bit lazier geometry, the triple clamp contributing to that geometry. If your building a K1600R I'd want the K front end. But you should be able to use either R or RS parts. Seeing as how you will probably have to completely reengineer the whole front anyway.
 

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Discussion Starter · #4 ·
That is what I thought as well :) The engine is a gem, but the rest of the bike is not my cup of tea, so to speak ;)

I had Nico Bakker in Holland build me a completely custom frame, so I'm using R1200R front suspension and K1600 rear, here are a couple of pics of the current state, it's far from ready obviously and a lot of parts are missing. It weighs around 206kg (454lbs) as it stands now:

109711

109712

109713
 

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Mark – 2015 R1200R-LC Exclusive
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The bike's looking great, Thomas! If anyone is going to build a good frame for your project, it's Nico Bakker. Didn't he do something similar in a GS version?

The steering geometry differences between the R and RS have long been a conundrum for me (since they were both released in 2015).

The specs say the wheelbase of the RS is longer by 15 mm - which could be put down to the frame, perhaps to re-balance the centre of mass given the extra weight of the fairing.

The steering angle specs for both bikes are the same at 62.3°.

The top fork clamp has an identical part number for both bikes, which means (you'd expect) that the bottom fork clamp has the same offset if the machined fork leg apertures are to be parallel (which they surely need to be) – and yet the castor of the RS is 114.8 mm compared to 125.6 for the R (10.8 mm shorter). To me, this could only mean the RS axle is offset from centre, away from the bike, by 9.6 mm compared to the R (the R axle seems to be centred) – which is hard to pick from pictures on the internet. If this is the case (and I can think of no other way to achieve the RS's geometry) then it should be readily visible by close examination of the actual part.

As you say, the two models have some part number differences for the forks. Significantly the fork spring set has a different number – perhaps to cope with the front-mounted additional weight of the RS fairing. I don't know that the RS forks would be longer as has been suggested – the claimed seat height for both models with the same seat is identical (although this could be a relatively approximate measure – hard to believe though, for Germans).

I'm not sure if this helps you in any way ...
 

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Mark – 2015 R1200R-LC Exclusive
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Photos on eBay of RS forks for sale seem to bear out my hypothesis. The axle appears to be offset as suggested, and the caliper mounting castings are also shorter to compensate. The third picture is of my R - note the longer caliper mounting lugs, and that the axle mount casting does not stand proud of the vertical bracing like the RS forks. EDIT: The axle also seems to be lower set in the casting than the R.

109714


109715

109716
 

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Discussion Starter · #7 ·
Thanks :) Yes he did, my initial plan was to modify the R1200R frame, but I realized it would be almost impossible, then I found his "K1600GS" and contacted him and he then built this frame for me.

Excellent. the difference is now quite obvious, I think I should really try to find a pair of R legs then, since the wheel base of my bike is longer anyway. Stiffer fork springs might be a good thing though, to cope with the increase in weight, but that could be sorted anyway.
 

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Mark – 2015 R1200R-LC Exclusive
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I think I should really try to find a pair of R legs then, since the wheel base of my bike is longer anyway.
The reduced trail of the RS forks might offset the overall long wheelbase though, notwithstanding a small increase in wheelbase. Nico would be able to advise.

The different part number for the lower triple clamp remains a mystery. It could be something as simple as a screw-hole for mounting a cable guide, different location for the steering stops, or a different offset for the steering damper mount. Again, direct comparison should be revealing, but I can’t find appropriate images on the ‘net. You could pop into a dealer and check out the showroom?
 

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Mark – 2015 R1200R-LC Exclusive
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BTW, rather than the R1200R headlight, have you considered going full post-apocalyptic Mad Max and fit a K1300R asymmetric headlight?
 
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The bike's looking great, Thomas! If anyone is going to build a good frame for your project, it's Nico Bakker. Didn't he do something similar in a GS version?

The steering geometry differences between the R and RS have long been a conundrum for me (since they were both released in 2015).

The specs say the wheelbase of the RS is longer by 15 mm - which could be put down to the frame, perhaps to re-balance the centre of mass given the extra weight of the fairing.

The steering angle specs for both bikes are the same at 62.3°.

The top fork clamp has an identical part number for both bikes, which means (you'd expect) that the bottom fork clamp has the same offset if the machined fork leg apertures are to be parallel (which they surely need to be) – and yet the castor of the RS is 114.8 mm compared to 125.6 for the R (10.8 mm shorter). To me, this could only mean the RS axle is offset from centre, away from the bike, by 9.6 mm compared to the R (the R axle seems to be centred) – which is hard to pick from pictures on the internet. If this is the case (and I can think of no other way to achieve the RS's geometry) then it should be readily visible by close examination of the actual part.

As you say, the two models have some part number differences for the forks. Significantly the fork spring set has a different number – perhaps to cope with the front-mounted additional weight of the RS fairing. I don't know that the RS forks would be longer as has been suggested – the claimed seat height for both models with the same seat is identical (although this could be a relatively approximate measure – hard to believe though, for Germans).

I'm not sure if this helps you in any way ...
I knew the caster and wb differences and assumed a slight rake and thus longer forks was the obvious reason. I would think offsetting the axle would create a scrubbing effect and substantially increase steering effort at low speeds. And I thought I looked the RS over pretty thoroughly before buying my R, at least I learned something today, thanks!

Now that I have seen the K1600R the only question is when do I get to ride it? Looking good, you have to keep us updated.
 

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Mark – 2015 R1200R-LC Exclusive
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Mark – 2015 R1200R-LC Exclusive
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BTW @K1600R – any prospect of adjusting the coolant plumbing so that the radiator can be moved up into the vacant space under the tank?
 

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Mark – 2015 R1200R-LC Exclusive
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Speaking of naked K1600's this is a nice example from a professional custom house.

My German isn't very good but I think he said something like, 'It goes like stink.'
 
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Discussion Starter · #14 ·
The reduced trail of the RS forks might offset the overall long wheelbase though, notwithstanding a small increase in wheelbase. Nico would be able to advise.

The different part number for the lower triple clamp remains a mystery. It could be something as simple as a screw-hole for mounting a cable guide, different location for the steering stops, or a different offset for the steering damper mount. Again, direct comparison should be revealing, but I can’t find appropriate images on the ‘net. You could pop into a dealer and check out the showroom?
I actually just asked a guy at the local dealer, he went looking and the only difference he could see were the steering stops, they were thicker on the RS limiting the steering a bit compared to the R as I understood.

BTW, rather than the R1200R headlight, have you considered going full post-apocalyptic Mad Max and fit a K1300R asymmetric headlight?
Nah, not really :) I kind of like to keep it looking like a stock R1200R as much possible.

BTW @K1600R – any prospect of adjusting the coolant plumbing so that the radiator can be moved up into the vacant space under the tank?
After speaking to Nico about their K1600GS build I realised I'll need every bit of space available, there is a lot of wiring and boxes etc. that will need space, the plan is also that the K1600 oil cooler will sit just above the radiator. Not to mention I also need space for an actual fuel tank under the covers, the intake manifold as well as the throttle housing takes up a lot of space under there.
 

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Discussion Starter · #15 ·
Speaking of naked K1600's this is a nice example from a professional custom house.

My German isn't very good but I think he said something like, 'It goes like stink.'
Yeah, I have seen that one before, some nice details, but the front suspension of the K1600 is but ugly if you ask me :D
 

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Yeah, I have seen that one before, some nice details, but the front suspension of the K1600 is but ugly if you ask me :D
Repackaging the electronics and getting all tidy and professional looking seems like quite a task. Personally, I love the funky K1600 front end, that was a major part of the draw to the K1200R for me.
 

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Mark – 2015 R1200R-LC Exclusive
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I realised I'll need every bit of space available, there is a lot of wiring and boxes etc. that will need space, the plan is also that the K1600 oil cooler will sit just above the radiator. Not to mention I also need space for an actual fuel tank under the covers, the intake manifold as well as the throttle housing takes up a lot of space under there.
Ah, of course. A big task ahead of you.

I hope you’ll keep us posted along the way.
 
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They are not interchangeable
There is a difference in the caster built in(look at a desk chair casters wheels),that is the reasons of different PO#.
 

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Discussion Starter · #20 ·
They are not interchangeable
There is a difference in the caster built in(look at a desk chair casters wheels),that is the reasons of different PO#.
Thanks, yes, that is what we have already established above, but in a rather more lengthly explanation :)

Not interchangable per say, but in this application I could probably go for either one given that I'll need both legs. And depending on what the overall geometry will be, since the rake is much steeper on this frame.

It seems the front mud gard is different also, to put it in the correct position to the wheel I'm sure.
 
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