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1Back to top Go down   Frame & Fairing Compatibility Empty Frame & Fairing Compatibility Sun Jan 26, 2014 8:46 am

MikeP

MikeP
Life time member
Life time member
Spurred by a comment someone made about swapping bodywork, essentially turning a 16v K100RS into a K1 and knowing that there is a lot of "under the skin" differences between the two models, I thought I'd take a look at the compatibility of the frames.

Probably like many K-Series owners, I'd assumed that owing to the generic nature of the design and build of the K-Series (up to the 1200), mixing and matching between models would be a relatively simple task.

I knew that with the launch of the K1, the frame tubes were beefed-up (up to 32mm diameter from 30mm) and that the steering angle was steepened thereby changing the rake (27 deg) and trail (90mm).

The K100RS 16v was given the same, stronger frame but I can find nothing to confirm that the steering angle change was carried over, except that some specifications list the wheelbase as the same between two.

You'd think then that these two bikes would share the same part number for the frame but not so. It took me a little while to work out why:

The K1 doesn't have rubber inserts in the mounting points whereas the 16v RS does, plus, the K-RS 16v has the same swing-out lifting handle that has adorned all the K-Series from launch but the K1, owing to the bodywork covering the rearmost frame downtube, has a short horizontal tube that joins the downtubes above the gearbox mounting to assist lifting onto the main-stand instead.

The K1100LT shares the frame with the K-RS 16v but not the K1100RS. This surprised me at first but again it seems to be down to the lifting handle: The K1100LT has the 'traditional' one but the K1100RS has a fixed tube attached to the rear downtube running up to the rear frame (again a consequence of body panel arrangements).

The K100RS (8v) & RT/LT share the same frame but the K100C is different (I believe only inasmuch as the former have rubber inserts in the forward mounting points).

All the K75 models, C, S and RT share the same frame. Unlike the faired K100 models, the 75RT doesn't have rubber inserts in the forward mounting points (presumably because the triple is less prone to vibrations).

Swapping fairings etc looks therefore to be a much easier exercise for owners of the 8v K100 and K75 models (the K75 models have a slightly different fuel tank too except for the K75RT which uses the K100 tank).

Things are less simple for the 16v bikes and swapping some 16v bike panels over to 8v bikes is further complicated in the case of the LT by the fact that the whole fairing of the K1100LT was shifted forward by between 30 and 40mm (different sources quote different figures). This means that the support brackets are not compatible.

Of course, as some owners here have demonstrated, it is possible to swap the bodywork but it's not as straight-forward as the apparent similarities would make it appear. There are far more detail differences than I ever thought.


__________________________________________________
1992 K1
1993 K1100R (used to be an LT)
    

2Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Sun Jan 26, 2014 10:57 am

duck

duck
Life time member
Life time member
And then there's also the "missing" cylinder on the front of the K75 engine which further complicates matters as it changes the angle of the frame "downtubes" and radiator mounting.

Also, the K1100RS has a "Y" under the tank while all of the other Ks just have a single frame member.

I've never measured it but I'm pretty sure that the 4V bike frames also have a slightly wider rear section to deal with the added width of the paralever swing arm hump and stepped out backs of the peg plates.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

3Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Sun Jan 26, 2014 1:22 pm

MikeP

MikeP
Life time member
Life time member
Apologies. I've just realised that I've posted this in the wrong section.


__________________________________________________
1992 K1
1993 K1100R (used to be an LT)
    

4Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Sun Jan 26, 2014 5:23 pm

SteveK1

SteveK1
Silver member
Silver member
This is interesting information, not really available elsewhere.  Thanks for posting.


__________________________________________________
BMW K1 1990
BMW R60 /5 1973
BMW R100R 1992
Honda CB360T 1975
    

5Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Mon Jan 27, 2014 12:23 am

Rick G

Rick G
admin
admin
duck wrote:And then there's also the "missing" cylinder on the front of the K75 engine which further complicates matters as it changes the angle of the frame "downtubes" and radiator mounting.

Also, the K1100RS has a "Y" under the tank while all of the other Ks just have a single frame member.

I've never measured it but I'm pretty sure that the 4V bike frames also have a slightly wider rear section to deal with the added width of the paralever swing arm hump and stepped out backs of the peg plates.
I am not 100% sure but didn't the LTs have that Y section after the big changes in late 1993. I seem to remember seeing a 94LT frame and thinking it was marked incorectly but found later that after late 93 all were the same.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

6Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Mon Jan 27, 2014 7:08 am

AL-58

AL-58
Life time member
Life time member
My '99 LT frame had the "Y" at the steering head.  The shape under the tank was different to suit also.

Al


__________________________________________________
'93 K1100LT
'08 F650GS (798cc)
'19 R1250RS

+ another boxer engined motorcycle and sidecar

"When I'm too old and too foolish to handle a sidecar I'll buy a Sportsbike"

Frame & Fairing Compatibility K-dogs10
    

7Back to top Go down   Frame & Fairing Compatibility Empty Re: Frame & Fairing Compatibility Wed Jan 29, 2014 8:39 am

Rabidchiwawa007

Rabidchiwawa007
Platinum member
Platinum member
Great info.  On the same note, awhile back i owned a 1985 K100.  Then i sold it after I bought my now 1992 K100 16v.  Do the 16v bikes have a smaller frame overall?  As I switched between the two, the 16v felt slightly smaller and my knees were a bit closer to the fairing.  Also, there seemed to be a slight size difference when I set the two next to each other.  The '85 just seemed a bit beefier.

Does this possibly have to do with different wheel / tire sizes among other things aside from frame?


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

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