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86 K75 Forks, calipers and rotors on an 83 R100/T

rowens816

Professional Slacker
Consider the following:

83 R100/T engine, frame, subframe, transmission and final drive.

I have the following parts laying around, and I want to mate these to the R100 frame. Is it possible?

86 K75 Brick front forks, calipers, rotors and axle (25mm)

OEM BMW FRONT WHEEL HUB FOR 1988-1995 R100R, R100 MYSTIC, R100GS

Does anyone know of any immediate problems I have not considered in lacing this 40-spoke hub to maybe an Akront rim, and mounting the whole shebang to the 83 R100? My obvious concern is if the spokes can clear the front brake calipers. :dunno

For some of you, call 911 now before the stroke kills you. :blah
 
Consider the following:

83 R100/T engine, frame, subframe, transmission and final drive.

I have the following parts laying around, and I want to mate these to the R100 frame. Is it possible?

86 K75 Brick front forks, calipers, rotors and axle (25mm)

OEM BMW FRONT WHEEL HUB FOR 1988-1995 R100R, R100 MYSTIC, R100GS

Does anyone know of any immediate problems I have not considered in lacing this 40-spoke hub to maybe an Akront rim, and mounting the whole shebang to the 83 R100? My obvious concern is if the spokes can clear the front brake calipers. :dunno

For some of you, call 911 now before the stroke kills you. :blah

Hi,
I would love to put a spoke wheel on the front of this bike,
It has a 1987 K75 forks and front wheel.
Dean

1107210260_Nc5u5-XL.jpg


1107211589_k7hWG-XL.jpg
 
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Beautiful bike, bad attitude

No doubt you should be very proud of your bike.

But we all have to battle the non riding public regarding loud bikes, like you proudly say yours is. You like waking the neighbors? Is this a joke? Are you serious?
 
The chrome on my /5 headers is shot and this looks like a great fix.

What is the width of the exhaust wrap (2" ?), and how many feet of it did you need for the headers and cross-over? Did you spring for the $5 a piece "clamps" they offer or did you use "safety wire", etc.?
 
No doubt you should be very proud of your bike.

But we all have to battle the non riding public regarding loud bikes, like you proudly say yours is. You like waking the neighbors? Is this a joke? Are you serious?


Waking the neighbors was just a figure of speech, I have a K bike thats very quiet, which I ride more than this one, so every once in a while l love to get this thing out and fire it up, it makes this 55 year old basterd feel alive,..I guess there's still a little rebel left in me.
I'm not sure where you live, but my neighbors don't mind it.
It's not like a ride it everyday.
You must live in California
 
The chrome on my /5 headers is shot and this looks like a great fix.

What is the width of the exhaust wrap (2" ?), and how many feet of it did you need for the headers and cross-over? Did you spring for the $5 a piece "clamps" they offer or did you use "safety wire", etc.?

I had a crappy looking set of headers too, so this $20 fix sounded good and doesn't look bad either. Yeh they are about 2" wide, it came with the stainless zip-ties, 25 feet I believe and I have some left over.
The first time you run the bike it burns and smokes alot, but after about 15 minutes it clears up, it was also black when I put it on. I'm thinking all toll with shipping it was about $25.
 
So, black turned to white (more or less). I was thinking maybe the "natural" color might work. My /5 is black. Is there any "powdery" residue associated with them after the burn in?

I've heard that rust can be a problem with header "tape". I guess that's just a reason to get out a pound it more often.
 
Going back to DAP Spackled's original post, the place I would look for guidance is the "All Balls Racing" bearing website. They have a database of the ID and OD of the steering head bearings for most motorcycles.

https://www.allballsracing.com/index.php/forkconvertion

I checked their table and it shows that both the K75 and R100 used the same steering head bearings. Your next step is to find out if the steering stems and yokes are of similar length and offset (from the stem to the tubes). I wouldn't be surprised if they were the same since the air head monos used K bike forks.

If the stem and yokes don't fit, you could look for a set from an airhead mono to see if they worked any better.
 
So, black turned to white (more or less). I was thinking maybe the "natural" color might work. My /5 is black. Is there any "powdery" residue associated with them after the burn in?

I've heard that rust can be a problem with header "tape". I guess that's just a reason to get out a pound it more often.

Yeh, I'm thinking I might of just got some cheaper stuff, because I've seen bikes where it didn't change color, I haven't noticed any residue at all.
 
Dean, the look of that bike nearly took my breath away. Fantastic.

That is the look I am also working on now. Not exactly, of course, but very similar. I have the engine, transmission, frame and final drive (33/11) from an '83 R100/T. The engine is in the process of total rebuild. The frame has already been powdercoated gloss black.

I have the entore ftont end from an '86 K75 --- forks, rotors, Brembo calipers, triple tree and axle. I have also gotten the hub from a R100R as previously stated. I want to lace it to an 18" rim and use a spare rear drum hub from a '78 R100RS laced to a new 18" rim.
 
I have a '93 R100R with an 18" front rim that I want to convert to a 19" rim maybe from an R1100GS. Maybe we can work something out.

Tom
 
Dean, the look of that bike nearly took my breath away. Fantastic.

That is the look I am also working on now. Not exactly, of course, but very similar. I have the engine, transmission, frame and final drive (33/11) from an '83 R100/T. The engine is in the process of total rebuild. The frame has already been powdercoated gloss black.

I have the entore ftont end from an '86 K75 --- forks, rotors, Brembo calipers, triple tree and axle. I have also gotten the hub from a R100R as previously stated. I want to lace it to an 18" rim and use a spare rear drum hub from a '78 R100RS laced to a new 18" rim.

Thanks..yes, I like the way it turned out, but there is still a lot of stuff I want to change, I have a stainless rear rim and some spokes I want lace to a black powdercoat hub and some larger rubber back there, the tire I have on there now is way to skinny (looks like a front tire). I'm very qurious to see what you come up with mounting a spoke hub to those K75 forks
 
K75 front end

Here is the complete K75 front end I have for this Cafe Racer project. Not pictured are the rotors and calipers.



I am not wild about the top brace of the triple tree. It appears to be the same flat steel as used on many of the airheads. I have seen better billet looking top trees with integral bar clamps and risers. Perhaps I need to get one of those.

Here is the front hub for an R100R Mystic, I think. Notice that the holes for the spoke nipples are in the hub. The wheel bearings are sized for the K75 25mm front axle.



Now, obviously, the stock K75 wheel bushings will are not enough to center the hub. I will have to take carefull measurements and have some bushings made. This was the part of the my post and questions where I hoped someone had been there before. I seriously doubt that I am the first person to have tried this conversion.



I have a line on a 2.5" x 18" Akront wheel. I hope to lace it to this hub.

Comments welcome.
 
Here is the complete K75 front end I have for this Cafe Racer project. Not pictured are the rotors and calipers.



I am not wild about the top brace of the triple tree. It appears to be the same flat steel as used on many of the airheads. I have seen better billet looking top trees with integral bar clamps and risers. Perhaps I need to get one of those.

Here is the front hub for an R100R Mystic, I think. Notice that the holes for the spoke nipples are in the hub. The wheel bearings are sized for the K75 25mm front axle.



Now, obviously, the stock K75 wheel bushings will are not enough to center the hub. I will have to take carefull measurements and have some bushings made. This was the part of the my post and questions where I hoped someone had been there before. I seriously doubt that I am the first person to have tried this conversion.



I have a line on a 2.5" x 18" Akront wheel. I hope to lace it to this hub.

Comments welcome.

Are you sure that front end is from a K75? I've never seen one with the airhead top plate, that looks just like a set of forks I just removed from 88 monolever R100RT, my K75 tubes are 42mm, the R tubes are 36mm.
 
I just measured the tubes: 38.41mm

I also just noticed that both forms have "Forking by Frank" lasered near the top. Obviously, these are aftermarket tubes by Frank.

What on earth do I have? I bought these on FleaBay ans they were advertised as '86 K75 forks. I know nothing about Bricks, and assumed they were correct. However, as I have researched parts, I too have never seen a similar top plate listed for K-bikes.

What do you think these could be?
 
I just measured the tubes: 38.41mm

I also just noticed that both forms have "Forking by Frank" lasered near the top. Obviously, these are aftermarket tubes by Frank.

What on earth do I have? I bought these on FleaBay ans they were advertised as '86 K75 forks. I know nothing about Bricks, and assumed they were correct. However, as I have researched parts, I too have never seen a similar top plate listed for K-bikes.

What do you think these could be?

If they were done by frank, that kinda explains the odd 38.41mm size, They probably are K fork bottoms and with the odd tube size they decided to just lay a flat steel airhead top clamp on them, maybe they couldn't find a top clamp to fit the tubes
 
Yep, you have a set of forks from a monolever airhead.
They came with the bigger tubes, I found this info for the R100 Monolever:
Telescopic fork with hydraulic shock absorber, 38.5mm stanchion tube diameter.
 

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