Author Topic: USD fork swap  (Read 17245 times)

Offline gsxrpig

  • ^ Motobrick Curious
  • Posts: 72
USD fork swap
« on: July 21, 2016, 02:37:42 AM »
Posted this in the second half of another post.
BUT
has anyone successfully swapped a 92 gsxr 750 front end into a k100??
With stock clip ons.  I have found one person but he used above triple bars.
Worried about turning circle and tank clearance.
Got the k100 down to bare frame so was thinking of bringing the tank mounts back 50mm???  Any issues with that idea?
And maybe shaping the front of the tank to allow a bit more clearance?.
I can't seem to find a definite answer??
I have a spare front end that I would love to use.
Then I was going to use a k1100 rear to give me a better tyre selection
Any tips or points to relevant topics or threads would be great.
Thanks in advance..great forum
  • Queensland, Australia
  • 90 k100LT

Offline sj2000

  • ^ Proficient Motobricker
  • Posts: 124
Re: USD fork swap
« Reply #1 on: July 25, 2016, 04:59:41 PM »
Maybe you could ask paul in his blog page for the clip on
http://www.pipeburn.com/home/2014/05/16/84-bmw-k100rs-paul-hutchison.html
I am trying to convert the front end also using 2003/4 GSXR front end, unfortunately I have not able to finish it yet.
I have not found any pictures with the raised fuel tank but some with modified tank, I don't know if it is raised or not.
http://www.bottegabastarda.it/portfolio-items/bmw-k100-cafe-racer-bobber/
http://www.pipeburn.com/home/2015/10/14/bmw-k1100rs-cooters-cafe.html

  • Parker, USA
  • 1985 K100

Offline sj2000

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  • Posts: 124
Re: USD fork swap
« Reply #2 on: July 25, 2016, 05:03:52 PM »
better solution is maybe raised the framed like the picture below rather than modifying the gas tank.
http://www.bikeexif.com/k100
  • Parker, USA
  • 1985 K100

Offline gsxrpig

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  • Posts: 72
Re: USD fork swap
« Reply #3 on: July 25, 2016, 06:46:24 PM »
Thanks for the reply.
The Hornet he used 2000 R1 forks.  Different beast.  I would love to get an email to the owner but have no idea how to contact him??
I have a 92 Gsxr front end in the shed.
This is where I am at with it.
It is just a mock fit up, so have to get the stem machined, but I am going to push ahead.
It hits the bottom seem of the tank before full lock up.
Had to shift the clip ons from there factory position.  Normally on this model they bolt back up to the top triple to set them into position.
If it works I may look at getting a set of aftermarket clip ons with double bolt fixings.
I will post results.
I will get them to work but the riding results may be a whole different can of whiparse....only one way to find out.. :falldown:
  • Queensland, Australia
  • 90 k100LT

Offline sj2000

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  • Posts: 124
Re: USD fork swap
« Reply #4 on: July 25, 2016, 07:44:20 PM »
are you going to still use bmw oem switch control or suzuki? it looks like you have a different lever.
  • Parker, USA
  • 1985 K100

Offline gsxrpig

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Re: USD fork swap
« Reply #5 on: July 25, 2016, 07:59:28 PM »
Just for looks at the moment.
Will try and keep the Bmw switchblocks.
But I have read that most need to upgrade the master cylinder to accomodate the upgrade in brakes.
That is a way off at the moment.  Just need to get the forks to work.
  • Queensland, Australia
  • 90 k100LT

Offline rbm

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  • Posts: 1941
Re: USD fork swap
« Reply #6 on: July 25, 2016, 09:36:48 PM »
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline gsxrpig

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  • Posts: 72
Re: USD fork swap
« Reply #7 on: July 25, 2016, 09:48:20 PM »
Hi Rbm.
Yep, I have.
BUT he bolted his bars to the top of the triples. 
I was all excited when I saw the post but it ended pretty quickly.
Nothing in there about tank clearance.  My set up here, the forks hit the bottom edge of the tank.  I have swang the clip ons out of the way so they will work,  next will be turning circle dramas.
I need to get a stem machined and pressed in then start working on some new steering stops on the frame.
With the bars on top it eliminates clip on problems but that is not the look I am after.
  • Queensland, Australia
  • 90 k100LT

Offline racket

  • Motobrick Curious
  • Posts: 45
Re: USD fork swap
« Reply #8 on: July 26, 2016, 09:11:20 AM »
A guy over at dotheton.com put GSXR forks on his K100. I think there were issues with sharp turns. And as others have pointed out, people seem to have managed R1 front forks but I'm guessing it involves a lot of machining and probably isn't cheap even if you get the forks for free.
  • Philadelphia, PA
  • 1986 BMW K100

Offline sj2000

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  • Posts: 124
Re: USD fork swap
« Reply #9 on: July 26, 2016, 11:23:02 AM »
  • Parker, USA
  • 1985 K100

Offline rbm

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  • Posts: 1941
Re: USD fork swap
« Reply #10 on: July 26, 2016, 05:37:25 PM »
An USD fork known to work well with the K100 headstock is the Ninja ZX7R front end.  Requires different 52mm bearings, but stem length is right on.  Uses Standard 20mm axle just like K100, only needs wheel spacers.  Uses 52/34mm roller bearings but need to turn stem down only few 1/10 mm to size for bearing. Press out steering stem, turn on lathe, reinstall in lower triple.  I'd Advise to pin the stem for security.  Can also use aftermarket triple with adjustable offset instead of the stock triple to set fork rake.  Standard Nisin brakes fit 320mm disks on K100 wheels.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline gsxrpig

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Re: USD fork swap
« Reply #11 on: July 26, 2016, 07:22:23 PM »
Rbm
Yes I saw that in an article somewhere about the Kawasaki front.
Problem is my Gsxr front is mine already, sitting in my shed wanting to be used...lol
I think it will be an easy turning job as well.
Just need to get a different top bearing as the standard bottom fits the Bmw.
The design of the shaft will allow the new bearing to be fitted further down the shaft and both threads will be cut the same distance down also.
Trying to track down a old fitter and turner I use to know to see if it is possible.
Will let you know the results.
Thanks
for the reply as well.  I appreciate all the ideas.
  • Queensland, Australia
  • 90 k100LT

Offline rbm

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  • Posts: 1941
Re: USD fork swap
« Reply #12 on: July 27, 2016, 08:31:44 AM »
You could consider replacing the OEM triple with aftermarket offset triple that will be adjustable.  That way, you can increase the clearance between the tank and forks, preventing the interference.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline gsxrpig

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Re: USD fork swap
« Reply #13 on: July 27, 2016, 07:06:34 PM »
Yep.  i am considering the clip on swap definitely.
Have to wait a week to get my tapered bearings.
Just spoke to the engineer and booked it in for late next week.
Press the stem out and continue the top bearing mount down about 20mm then redo both top threads the same cut off the excess and should work.
Thinking of putting in a locking grub screw to lock the shaft after it is pressed back in.
  • Queensland, Australia
  • 90 k100LT

Offline sj2000

  • ^ Proficient Motobricker
  • Posts: 124
Re: USD fork swap
« Reply #14 on: August 05, 2016, 09:55:02 AM »
Do you have the pictures? I am sure it will be beneficial for all of us, specially if you could write the steps also.
  • Parker, USA
  • 1985 K100

Offline gsxrpig

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Re: USD fork swap
« Reply #15 on: August 05, 2016, 08:28:06 PM »
Still waiting on bearings mate, so I am at a standstill.
Will keep you posted.
  • Queensland, Australia
  • 90 k100LT

Offline gsxrpig

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Re: USD fork swap
« Reply #16 on: September 26, 2016, 11:08:27 PM »
Work and other projects have kicked me in the pants and stopped me on the Bmw.
Forks fitted.
Rear cowl glassed and ready for prep.
Tank is welded and actually holds fuel...hahaha
Seat base is a work in progress.
NOW i have moved onto wiring...The nightmare has begun..lol
This is my aim and please tell me if I am crazy.
Because I am using the GSXR front end I thought I would use the switchblocks and clip ons as well.  I have spoken to a few guys and they feel I need to bulk up the master cylinder to be successful with the 4 pot calipers on the gsxr.  I have the switchblock handle and master cylinder there to use...so I will have to blend these into the bmw system which is pretty similar except the auto cut off on the indicators and the indicators switch is entirely on the LHS.    I am happy to attack this.
BUT next I have decided to use the gsxr instrument panel also.
Uses the front wheel to feed the speedo with a cable so that will be easy.
Nice functional Tacho
and a Temp gauge.
The only dash lights are  indicators left and right
High beam
Oil light
and finally Neutral light.
I have a gear indicator light on its way also.
The issue here will be getting everything to work without the BMW instrument panel which is like a brick but a very smart brick :hehehe
Eliminating a lot of features but how to trick the computer to allow me to use the bike normally will be my issue.
Been trying to research and have considered the motogadget.  It seems expensive but firstly I would love someone to indicate if what I am doing is in fact, even possible.  The motogadget would seem cheap if I spend a month trying to get the gsxr stuff to work and in the end it was never even possible.
Thanks in advance..open to any help advice or opinions.
  • Queensland, Australia
  • 90 k100LT

Offline rbm

  • ^ Quintessential Motobricker
  • Posts: 1941
Re: USD fork swap
« Reply #17 on: September 27, 2016, 06:22:55 AM »
... This is my aim and please tell me if I am crazy.
...  I have the switchblock handle and master cylinder there to use...so I will have to blend these into the bmw system which is pretty similar except the auto cut off on the indicators and the indicators switch is entirely on the LHS. 
Ditch the BMW signal relay and replace it with a compatible Japanese signal relay, hopefully a LED compatible one because you probably will also follow the mainstream tactic of substituting LEDs for globes.  While you're at it, consider replacing the vast majority of the signalling wiring by using a Motogadget M-unit.

Been trying to research and have considered the motogadget.  It seems expensive but firstly I would love someone to indicate if what I am doing is in fact, even possible.  The motogadget would seem cheap if I spend a month trying to get the gsxr stuff to work and in the end it was never even possible.
Thanks in advance..open to any help advice or opinions.
The choice of gauge is largely immaterial to the operation of the bike.  Many of the functions you loose by removing the OEM gauge are not replaced with the addition of an after-market gauge.  Surely the indicators and clocks replace equivalent functions in the OEM gauge.  However, functions such as Start Enable, Neutral Detect, RTC, Gear Indicator, Charge Indicator and so on are not available on any after-market gauge.  These functions will need to be simulated with additional circuitry.
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline duckytran

  • ^ Proficient Motobricker
  • Posts: 204
Re: USD fork swap
« Reply #18 on: September 27, 2016, 09:29:25 AM »
Check out Mike Flores K100 build. It's very similar to yours with the USD forks. His wiring is top notch. Perhaps you can pick his brain.

http://www.motobrick.com/index.php/topic,8807.0.html

Other than that, your build is looking very nice. Looking forward to seeing the finish product.

P.S. Did you get that custom rearset built or bought?
  • Austin, Texas
  • 1993 K75, 1981 R65

Offline gsxrpig

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  • Posts: 72
Re: USD fork swap
« Reply #19 on: September 27, 2016, 06:17:31 PM »
I made the rearsets...they are mixture of Gsxr pegs and master cylinder I had off another project and just made the brackets up on my cnc for the templates and got them locally watercut out of 10mm ally.  Bit of playing around but they will be nice.
Thanks for the tip on the wiring...I will head over to the link when I get time.
I had to step away from this build for a fair few weeks and unfortunately I will only get another week before other stuff will stall my progress.
Need some wiring done to keep me happy :clap:
  • Queensland, Australia
  • 90 k100LT

Offline gsxrpig

  • ^ Motobrick Curious
  • Posts: 72
Re: USD fork swap
« Reply #20 on: September 27, 2016, 06:29:38 PM »
Ditch the BMW signal relay and replace it with a compatible Japanese signal relay, hopefully a LED compatible one because you probably will also follow the mainstream tactic of substituting LEDs for globes.  While you're at it, consider replacing the vast majority of the signalling wiring by using a Motogadget M-unit.
The choice of gauge is largely immaterial to the operation of the bike.  Many of the functions you loose by removing the OEM gauge are not replaced with the addition of an after-market gauge.  Surely the indicators and clocks replace equivalent functions in the OEM gauge.  However, functions such as Start Enable, Neutral Detect, RTC, Gear Indicator, Charge Indicator and so on are not available on any after-market gauge.  These functions will need to be simulated with additional circuitry.
RBM thanks for the reply...I am in over my head as you can gather
I am actually going against the trend and not using LED's...lol.  Sticking with Globes on this one as the indicators I liked are in fact globes and I just like em.
My budget at the moment is screaming no to motogadget...but it would make my life easier.
The Gsxr instrument panel is pretty basic.  That was my question, the functions I do not use I will have to add something to trick the computer into thinking they are still in use.  That is where I will come unstuck :popcorm ,  I will chip away and see what I can find, someone will have done it,  so hopefully I can get some assistance because it truly is my weak point... :beehive:
  • Queensland, Australia
  • 90 k100LT

Offline gsxrpig

  • ^ Motobrick Curious
  • Posts: 72
Re: USD fork swap
« Reply #21 on: September 29, 2016, 02:55:06 AM »
Well after stuffing around all day.
I have Right hand switch block with kill switch.  Start switch.  Lights on/off
Left hand switch block with horn,  Hi and low beam, also Pass button AND Indicators.
BUT and with my electrical work there is always a but.
My indicators are flashing like crazy???  I kept the original wiring.  this may be an issue.
BRM if you are out there....I went and bought a relay and started as you suggested but got lost....although I was lost for a long time on trying to get the originals to work as well :beatdeadhorse:
Tomorrow I will get rid of the Bulb monitoring unit, but I read on another post that it will not affect the flashers..
They are 10 watt bulbs but it is acting like they are led's---- flashing fast.
I do have a 2 prong flasher I have used on another Led project with success...maybe put that inline and see?
Also need to sort out the rear taillight.
Any advice would be great..thanks in advance
  • Queensland, Australia
  • 90 k100LT

Offline rbm

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  • Posts: 1941
Re: USD fork swap
« Reply #22 on: September 29, 2016, 07:13:16 AM »
Gsxrpig,

Can you be specific about which control sets you are using?  Are they the ones from your donor 1992 GSX-R 750?

You are correct in saying that eliminating the BMU will not have any effect upon your flasher problem. 

A Japanese flasher circuit is quite simple.  A source of power connects to one side of the flasher, powering it.  The output on the second pin will be a source of regular 12V pulses that goes to the wiper of the indicator switch, a single pole double throw centre off switch.  The purpose of the switch is to route these regular pulses either to parallel connected lights on the left side or right side of the bike, depending on which side of the switch is selected.  The rapid flashing indicates too little electrical load, meaning you've introduced a wiring error. 

Can you post a schematic on how you connected your indicator circuit?  If it were me, I would
1. connect the Blue/Red and Blue/Black wires from the old flasher to the indicator switch in the left hand controls
2. connect the Green/Black wire from the old flasher to the new 2-pin flasher
3. run a new wire from the 2-pin flasher to the indicator switch in the left hand controls
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline racket

  • Motobrick Curious
  • Posts: 45
Re: USD fork swap
« Reply #23 on: September 29, 2016, 10:37:13 AM »
While you're at it, consider replacing the vast majority of the signalling wiring by using a Motogadget M-unit.

How much of the wiring harness can you actually replace with the m-Unit? I've seen varying reports
  • Philadelphia, PA
  • 1986 BMW K100

Offline gsxrpig

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  • Posts: 72
Re: USD fork swap
« Reply #24 on: October 03, 2016, 07:07:39 PM »
Hi RBM,
Sorry for the late reply, I was having trouble getting onto the site Friday and Saturday our time.  Then a long weekend. 
I am using a LHand switchblock off a 92 gsxr.
But a RHand switchblock off a 90 model.  I did this because the 90 has an on/off switch for the headlight.  So I can turn them off for start ups.
1990 BMW k100
So from LHAND suzuki colors to BMW
Yellow 3 black dots to White
White 3 black dots to Yellow
Yellow/White to White/Yellow
Orange/Red to Green/Blue
Black/White to Blue/Brown
Lt Green 1 black to Rhand side Blue/Yellow
Lt Blue 1 black to Rhand side Brown also Brown/White

RHAND switch block
Yellow/Green to Black/Yellow
Orange/Black to Black/Green also Green
Orange/White to Green/Yellow
Grey to Green/Blue
Orange/Blue to White/Yellow
Orange/Red to Grey/Blue]
Yellow/White suzuki unused.

BMU has been removed.
Grey/Black joined to 2 Grey/White
Grey/Yellow joined to Grey/Red and Grey/Green.

Tail light works with key switch in park.  But if you depress a brake pedal it goes off?
With the key fully on the tail light does not work but the brake light works as it should.
no power to fuse 2 when the key is fully on.

Hopefully you can get through my ramblings and see where the problem is.
I will have a better read of your post and see if I can get the aftermarket relay to work .
Thanks for the help BRM you are a legend. :clap:
  • Queensland, Australia
  • 90 k100LT

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