GSXR1100 (1991/1992) Fork upgrade

[FJNovaScotia]

Hey guys,

I've been searching all over for information on how to swap in a 1992 GSXR1100 USD fork into a 1989 FJ.   I see its been done via the following website:  http://www.fjmods.btinternet.co.uk/MarkAlva.htm.

Does anyone have any additional details?

I am committed now.   I just purchased a parts bike to do the swap. 

I'll keep you all updated on progress.

[FJNovaScotia]

The GSXRs that will be donating parts (One is a 90, the other a 91...all parts are there, pictures are taken while they were getting pulled apart)




The fork length is just 2 inches off of the FJ length.  This will be compensated by using handlebar mounts and a superbike bar.  Both bikes use a mechanical speedo so I'll be able to retain the FJ speedometer.   The FJ and GSXRs share the same steering stem diameter and have the same specs for the upper and lower bearings....the only problem is the stem length.   So I'm in the middle of pressing the FJ stem into the GSXR lower triple.

Some pix of the USDs compared against the FJ forks:





I know all this has been done before but I thought I would share anyway. 

All the best and more to come

[FJNovaScotia]

I'll try this again!

The GSXRs that will be donating parts (One is a 90, the other a 91...all parts are there, pictures are taken while they were getting pulled apart)








The fork length is just 2 inches off of the FJ length.  This will be compensated by using handlebar mounts and a superbike bar.  Both bikes use a mechanical speedo so I'll be able to retain the FJ speedometer.   The FJ and GSXRs share the same steering stem diameter and have the same specs for the upper and lower bearings....the only problem is the stem length.   So I'm in the middle of pressing the FJ stem into the GSXR lower triple.   I'll also be using the ignition switch from the GSXR.
.
Some pix of the USDs compared against the FJ forks:











I know all this has been done before but I thought I would share anyway.  

[movenon]

Doesn't matter whats been done before. I learn something from every project, even from the ones I have done before.  There is always more than one way to do things. Keep the pictures coming.    You can use the rear end stuff on your bike also.
George

[FJNovaScotia]

Yup already well on the way...








FJ rear sitting beside the 190 GSXR rear

[movenon]

That's about the stage mine is in. Start making new "dog bones" tomorrow. Hope to be done with the rear by the end of the month. Next month new wheel and tire. The forks are going to have to wait until later. Keep the photo's and progress reports coming.
George

[FJNovaScotia]

Hey George,

Will you be adding the Honda F4 shock as well?   I just picked one up and will be modifying over the next couple of weeks.

[bcguide]

Your timing on this is perfect for me.
I have been looking at buying a 1994 gsxr1100 and doing the same swap.  Do you think the rear swing arm would swap in to?

Scott

[FJNovaScotia]

The watercooled GSXR1100s (1993 - 1998) have a different swing arm then the oil cooled ones I have so I couldn't say.   The swing arm on the oil cooled looks very similar to the FJ. So I didn't see the benefit of the swap.

[movenon]

Hey George,

Will you be adding the Honda F4 shock as well?   I just picked one up and will be modifying over the next couple of weeks.

My FJ is a 1990. As soon as the dog bones are made and the canister is mounted then the f4i shock conversion is in and done... I am going to mount the canister after the brake stay is in place. Not the best picture but you get the idea .
George

[racerrad8]

George,

Every time I look at that photo I see the shock mounted upside down. Is that the way everyone is mounting this shock?

Randy - RPM

[racerman_27410]

Aint trying to tell anyone what to do but I agree with Randy.... looks upside down to me too.


KOokaloo!

Frank

[movenon]

Yea, its a grand experiment in futility... I am doing it "just because" I can. I know there are about a million reasons not to do this. It is just in my nature so said the fox to the chicken ......... I am doing no harm to the bike mounting points (other than the rider, me) so I can later install a better shock when I give up and surrender.
No, the shock is only upside down mounted in the later FJ's (89 and newer?). 

The early ones are mounted right side up and easier to deal with. I am just going to the 5.5 rear wheel and had a shock on hand and said what the hell, I am here.

Back in the old days I had a two stroke and decided that with a grinder and a ruler I should port it, great ran better, more porting, great power band about 200 RPM wide !, ported some more and you know that damn thing can run backwards...... Its just in my nature....
George

[Arnie]

Aint trying to tell anyone what to do but I agree with Randy.... looks upside down to me too.

Frank

It IS upside down.  Who cares?  There's a bladder between the oil and the nitrogen.
It would have been near on impossible to modify the stock lower mount and keep it upright.

Arnie

[SlowOldGuy]

Is there anything wrong with mounting a shock upside down?  Compression and rebound are still compression and rebound.

Does the nitrogen leak out when upside down?  :-)

Just curious.  We used to have this discussion when setting up the Sprint Car years ago.  Some would mount the shock with the body on the bottom so they could easily/quickly read the shock settings.  Others would mount the body on top for less unsprung weight.  AFAIK the shock performed the same.

Either mounting geometry would leak when he crashed the car.  :-(

DavidR.