K75S High Seat

devmat · Apr 25, 2015

My '91 K75S came with a low seat set up and I am in the process of going to the high seat. I bought this Corbin seat and once installed it has a big gap between the seat and the gas tank, is this for a different bike? All the mounting hardware line-up but this gap seems excessive.

jconway607 · Apr 25, 2015

Not that it will be of much help, but I have a Corbin on my K75RT and there is no gap between the seat and the tank. It fits right up against the tank. It would appear that seat is made for a different bike, or a different model of K. A picture sent to Corbin might solve the mystery.

devmat · Apr 25, 2015

I'm wondering if it's for a different K. The mounts match up, but it's not close to being flush with the tank. Here's a picture of the seat before installation.

6322 · Apr 26, 2015

Not sure why the gap exists. I'm taking a Corbin off of my K and installing the BMW comfort seat, but the Corbin had no fitment issues.

jad01 · Apr 26, 2015

jconway607 said:
Not that it will be of much help, but I have a Corbin on my K75RT and there is no gap between the seat and the tank. It fits right up against the tank. It would appear that seat is made for a different bike, or a different model of K. A picture sent to Corbin might solve the mystery.

I agree- I'd contact Corbin. Assuming there is no damage otherwise to the tank or its fitment on the bike, I think the seat should fit fairly flush against the tank. My low seat does…

drneo66 · Apr 27, 2015

Just trying to think outside the box - Is the gas tank seated properly with the little clips on the posts? I don't see the rubber tank pad on the rear of the tank, but even with that installed, I don't think you'd make up the room. There is some slight adjustment available by moving the seat latch around so you may able to get closer if Corbin says you've got the right seat. The older K seats came with the handles in the seat, so you would have ran out of room if you had an older K seat, as they are longer.

ldbeemer · Apr 27, 2015

Usually on the underside of Corbin seats is a sticker that lists the fitment. Check and make sure it isn't for a 1985, they were different and not interchangeable with other years.

Gene V.

PGlaves · Apr 27, 2015

ldbeemer said:
Usually on the underside of Corbin seats is a sticker that lists the fitment. Check and make sure it isn't for a 1985, they were different and not interchangeable with other years.

Gene V.

No such thing as an '85 K75. K100 yes. K75 no. But it could be an '85 K100 seat.

Also - I'm not sure but the low seat and high seat tanks were different - the low seat had the straps for the shroud clips. Maybe the low seat tank does not come as far back as the high seat tank.

ldbeemer · Apr 27, 2015

I converted my K75RT from the low seat to a Corbin high seat and did not have the gap shown. The amount of space shown looks like what would be filled by the fuel tank cover on the low seat set up. Could it possibly be a custom alteration that would have accommodated leaving on the fuel tank cover?

98lee · Apr 27, 2015

What you have is a rare, no longer produced, Corbin Smuggler seat for 1986 and up K75, K100, and K1100.
It IS the correct seat for your bike. You SHOULD get it to fit better by adjusting the hinges on the bottom of the seat or on the bike (especially the rear hinge that controls the fore and aft position).

Some seats get the top of the nose deformed (pulled back) for various reasons (upholstery too tight in the fore and aft direction, too green of a seat pan when covered, distortion caused later in life by heat and loading). But, yours looks parallel to the back of the tank, so I think you should just be able to move the hinges to get an acceptable fit.

It is definitely not an '85 seat. They have a square lower rear corner like the picture in 6322's post (because the stock hand holds are incorporated into the stock seat not the bike). 6322's seat is an aftermarket or recovered seat that eliminated the stock '85 hand holds. There is no difference between high seat and low seat tanks. Low seats use adhesive tabs to hold the rear rubber tank surround for the low seat to the tank. Corbin low seats do not use the surround.

:dance

98lee · Apr 27, 2015

PGlaves said:
No such thing as an '85 K75. K100 yes. K75 no. But it could be an '85 K100 seat.

Slight clarification:

In Europe, the K100 was introduced in '83 and the K75 in '85.

The K75C was introduced to the U.S. in late'85 as an '86 model model. The Ss came out in early '86 as '87 models.

The K 100 was introduced to the U. S. in early '84, but I'm not sure if it was as an '84 or '85 model.

:dance

devmat · Apr 27, 2015

drneo66 said:
Just trying to think outside the box - Is the gas tank seated properly with the little clips on the posts? I don't see the rubber tank pad on the rear of the tank, but even with that installed, I don't think you'd make up the room. There is some slight adjustment available by moving the seat latch around so you may able to get closer if Corbin says you've got the right seat. The older K seats came with the handles in the seat, so you would have ran out of room if you had an older K seat, as they are longer.

I'll check the tank next. I don't have a latch yet, so that's not a factor. If I just set the seat on on the bike using only the hinge pin and no brackets this is how close it gets. Right side seems to sit closer than the left.

devmat · Apr 27, 2015

The pan is marked K86R.

Thanks for all the responses.

mohler · Apr 27, 2015

That model is a Rumble, the Smuggler model didn't have the fold up backrest.

98lee · Apr 28, 2015

mohler said:
That model is a Rumble, the Smuggler model didn't have the fold up backrest.

Oops! You are correct. It's been so long since they made those for a K that I "misremembered" what they called them. I see they brought them back for Harleys and a couple of other bikes. Thanks for the quick correction.

PGlaves · Apr 28, 2015

98lee said:
Oops! You are correct. It's been so long since they made those for a K that I "misremembered" what they called them. I see they brought them back for Harleys and a couple of other bikes. Thanks for the quick correction.

That's OK Lee. We currently have two low seat K75s, on regular seat RT police bike, and a K75S and I always thought the tanks were different. Now I see the loops for the low seat shroud tangs are glued on. Sheesh!

98lee · Apr 28, 2015

BMW actually made at least 5 different tanks for the K75. Most differences were to the underside to accommodate different battery cover mounts and radiator shroud mounts.

However, the RT tank had more capacity (5.81 vs 5.54 gal.) in the area of the fuel pump and on the opposite side. This is the same tank used on post-'85 K100 and K1100 that have similar battery cover and radiator shroud mounts. This can be seen from the outside. This extra area is why an RT tank will not work on an S. The S fairing interferes with this area. DAMHIK.

The rear mounting pins were changed from 12mm to 10mm on 1/87. The front tank mounts were widened on 1/93.

But, the rear of the tanks are the same.

:dance

72r60/7 · Apr 28, 2015

5 tanks for the K75 ! I never would have thought.
That proves that what I know about a K75 would fit in a small thimble and be of no use to anybody but me, even after owning 3 at the present and one of them for 23 years.
I love it !

AntonLargiader · Apr 28, 2015

That's not an '85 seat, but if you are using it with a low seat tank the fit will not be great.

98lee · Apr 28, 2015

AntonLargiader said:
That's not an '85 seat, but if you are using it with a low seat tank the fit will not be great.

Uhm, there is no such animal as a low seat tank. Tanks on low seat bikes have the tank surround added. The mounts are held to the stock tank with double sticky back tape.

:dance

K75S High Seat

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