OK, so I'm the muppet who bought the wrong seat for my early 8V RS. The seat on it has completely gone, the cover is non existent and I have used an old leather jacket to try and cover it, the base is corroded beyond repair. So, I found a lovely one on eBay, I skipped to the shed with new seat ready for a quick half an hours work, attached it all, went to bring it down and it wouldn't go! Turns out I have bought the wrong one, the one I need has a flat (ish) base and this one has a lump in it!!!  

So, I can see they have the one I need in motorworks but they still have the metal base, is there any other that would fit with a plastic base as this seems to be a big problem.

Hope that makes sense!

Also, if anyone needs a seat in tan leather I have one!!!  

Thanks in advance 

Dave

Show the underside in a photo.

Early 8v has a steel base and handles in the seat,

Later one is plastic base and no handles.....they are in the ducktail. You would need ducktail and seat fittings.

K1100 one is also plastic base has a big lump goes down between frame tubes. But won't fit early ducktail. You would need ducktail and seat fittings.

But...what if you remove the cover of the underseat tool tray.......will it then close????

You must have a later comfort seat with the bulge under the pan for more front seat padding.  You can remove the tool tray for clearance, but I think that requires a different housing for the ECU.  Possibly just remove the tray lid.

Here is some of Duck's "Seat-a-palooza" offerings.

http://www.bmwkbike.dx.am/CLseats/kbikeseats.htm

Shows the pre-1986 has the incorporated handles as part of the seat pan, metal or plastic seat pan does not matter. The pre-86 Corbin seat does not have the incorporated handles. The pan is extended in that area.

Offerings currently on the interwebs across the pond

https://www.ebay.com/itm/Seat-Saddle-for-1985-BMW-K100/123890994573?hash=item1cd87a8d8d:g:FPsAAOSwqOFb2I1i

https://www.ebay.com/itm/BMW-1985-K100-CORBIN-Dual-Canyon-Touring-SEAT-K100-K100RS-K100RT-K-75/321547217333?_trkparms=aid%3D1110001%26algo%3DSPLICE.SIM%26ao%3D1%26asc%3D40718%26meid%3D2689893ae07b47089220e4b51078d982%26pid%3D100012%26rk%3D1%26rkt%3D12%26sd%3D123792332382%26itm%3D321547217333%26pmt%3D0%26noa%3D1%26pg%3D2047675&_trksid=p2047675.c100012.m1985

https://www.ebay.com/itm/BMW-K100-SEAT-FROM-1985/323902702088?hash=item4b6a1b0208:g:aW8AAOSwy2pdbXzO

You need a low seat brain(L-Jetronic/ECU) holder if the seat pan sticks down into the frame.

#9 here: http://bit.ly/2ly4ouA

More interwebs offerings across the pond for the pre-86 seat

Fehrer very nice condition

https://www.ebay.com/itm/BMW-Motorcycle-Seat-Fehrer-BLACK-Dual-Saddle-1984-85-K100-K100RS-RS-52534534970-/153639051329?&_trksid=p2056016.l4276

https://www.ebay.com/itm/BMW-Russel-Day-Long-Touring-Saddle-Motorcycle-Seat/273988302152?_trkparms=aid%3D555021%26algo%3DPL.SIMRVI%26ao%3D1%26asc%3D40719%26meid%3Db6af683ae6b94cfdad1f0ad082968184%26pid%3D100752%26rk%3D6%26rkt%3D9%26mehot%3Dpf%26sd%3D392320152820%26itm%3D273988302152%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100752.m1982

https://www.ebay.com/itm/BMW-Russel-Day-Long-Touring-Saddle-Motorcycle-Seat-Two-Tone-Beautiful/273988304024?_trkparms=aid%3D555021%26algo%3DPL.SIMRVI%26ao%3D1%26asc%3D40719%26meid%3D16095b6e53cc4b2284dc06ff6ac02117%26pid%3D100752%26rk%3D7%26rkt%3D11%26mehot%3Dpf%26sd%3D153639051329%26itm%3D273988304024%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100752.m1982#shpCntId

It might just be a matter of hinges adapted to the seat base. Because on the bike frame, the hinge holding points are the same whatever the bike year/seat design.

I did it the other way through: I have a k1100 which had a so called comfort seat. That seat had a plastic base.

As that comfort seat is not comfortable at all in case of long legs, I looked for a better design and found it in Motorworks here, Ref SEA50646

That one, which permits to be sitted 7cm further back has a steel base. The thing to do to adapt it on my k1100 was just to fit the hinges corresponding to that type of base. So I assume that it also works in the other direction.

Contact Motorworks, they know their business and will probably wish to keep their reputation when guiding you, even if you purchased your seat elsewhere and are just candidate to the purchase of hinges...

My 92 K100LT has a Comfort seat and it very much lives up to its name. It does not have the projection underneath so still has the tool tray. For me, 5' 8" I found it quite high but extremely comfortable. The K1100 seat is considerably lower and much more manageable.

I've just fitted a comfort seat which I think must be a K1100 type as it has the lump underneath.
Forums suggest you can cut the lump out but that sounded a bit vicious to me - I took the lid off my toolbox tray and cut the tray down by about an inch. All fits and can still get a few bits in the tray. Mine has a horrible rubber pad thing in the rear hinge which makes it feel a bit loose - till I sit on it :-)
Cheers
Steve

Apologies for jumping in on this thread, but I wanted to test my understanding.
Retrofitting a post 86 seat to a pre 86 bike needs mods as the later pan has a lump and the hinges are different?

I have an 85 metal pan seat which I have memory foamed and recovered, so I wouldn’t want to get rid. 

I have just bought  91 k1100 fairing in really good cosmetic shape and there may be an opportunity to get the matching seat cowl.

Can this mix and match work? I assume I end up with two grab brackets and would need to do something clever with hinges, but will the seat fit otherwise with no gaps back and front? Anyone know or done it?
Cheers.

No apologies necessary. However, I can only give you my own experience, but, I'm sure that the great and wise on here will be able to give much better advice than me.

I found that when I tried to fit the 1100 seat there were issues, firstly I had the issue with the lump, I did look in to cutting the lump off but though that was a bit much, So, I removed the tool tray lid, Yes it did fit, but, there seemed to be space a the rear of the seat, and not good space. It just looked like it didn't fit or belong, then the hinges needed relocating and then the rear grab rails would need some cleaver fixing. So..

In the end I bought a stock RS seat, not the most comfortable, but at least I knew it would fit without any issues! I will look in to something more comfortable before I head off to Europe, but for now, It looks great and does the job!

Not sure if this helps you, but, I'm starting to collect a lot of K parts that don't fit my K!!!! Maybe I should buy another K! 

Dave

Davep wrote:
Not sure if this helps you, but, I'm starting to collect a lot of K parts that don't fit my K!!!! Maybe I should buy another K! 

Dave

Subconciously, you already are. Sneaky stuff K pox   .
Thanks for the feedback.