FJ1100 fork conversion

[bikerphil]

I've decided to do an FJ1100 fork conversion on my 79F. Found a guy down in S. Miami with a whole warehouse full of 70-80's Jap parts, so I have most everything I need.



Problem is, the triple tree stem of the FJ is 22mm longer than the XS. The 2 ways of solving this problem are, 1. Press the stems out and fit the XS stem in the FJ lower tree, or 2. Machine a spacer to move the lower bearing race down 22mm. This is the drawing I came up with for the spacer. I just gotta find someone that's willing to make one for not too much.



Has anyone done this or somthing similar before?

Any insight would help.

[FJ111200]

I'm in the process of doing this but with an FJ1200 front end from 1988 onwards.
What i've done so far is, and it's not a lot, is to press out the steering stems from the FJ and XS lower yokes. The FJ one presses straight out as the yoke is aluminium and the stem is steel, but the XS one needs to be ground down first then pressed as it is welded to the yoke at the bottom. Then when the XS stem is pressed into the FJ yoke it needs a ring of strong weld on the bottom to stop it popping through the yoke when it's all tightened up.
Also, don't know if you know but, the FJ1100 and early 12's up to 1987 use 16inch front wheels and the later 12's from '88 on use 17inch front wheels. And, the 88 on 12's use 4 pot brake calipers with bigger brake discs whereas the 11's and early 12's use 2 pot calipers, smaller discs, and none of the parts are interchangeable, due to the different mounting points.
Hope this helps before you get too far down the line.
Almost forgot, i don't get your bit about moving the lower bearing race down.

[bikerphil]

i don't get your bit about moving the lower bearing race down.

Ok, the lower race is removed from the headstock. Then the custom spacer is pressed into where the lower race originally was. The race is then pressed into the spacer, lengthening the headstock 22mm. The FJ stem will now be the right length. No need to remove the stem from the FJ triple tree. This will also raise the frame up 22mm as opposed to using the XS stem in the FJ tree. I'm not sure what wheel to use yet, I still need to find an axle.

[FJ111200]

But what about the lugs on the lower yoke that stop the handle bars turning all the way round? Will the fact that they won't be in use affect the construction and use regulations? Or is it different in the US?

[bikerphil]

But what about the lugs on the lower yoke that stop the handle bars turning all the way round? Will the fact that they won't be in use affect the construction and use regulations? Or is it different in the US?

I figure once I have everything together, I can determine the correct position for the stop tabs and weld them to the spacer. I have the '85 FJ forks, but I'd like to use a 17" or 18" wheel, but definitely not a 16". There are no regulations in my state for any kind of inspection.

[chevy45412001]

bearing race

i just ran across similar problem with my xj. I put 750 front end on my 1100 after accident. The 750 was also longer in the middle bearing thingy. i just took a grinder to it to move the bearing rest spot down further. and ran two retainer rings on top. works fine....so far. but on the other hand wow the 750 used some very small rotors. like paper thin and smaller in diameter. But i live in florida now so down time does not come offten.

[bikerphil]

i just took a grinder to it to move the bearing rest spot down further.

Are you reffering to the upper bearing rest spot? How much longer was the stem that you used?

[bikerphil]

454, after looking at my FJ stem, that just might work. That would raise the upper TT and bars up some which would be a good thing. The bad thing is losing almost an inch of frame height. It wouldn't be a problem if I was using the stock 19" front wheel, but with smaller front rim and lower profile tire, it might be too low. Gotta think about that for a bit, thanks for the idea.

[bikerphil]

update

Well, I decided to move the upper triple tree bearing down on the stem 22MM. Had to take .5MM thickness off the stem for the bearing to slide down enough. Did it with strips of 40 grit belt sander sandpaper by hand. Took a couple hours but turned out fine.



The fork assembly is on the bike with a temporary spacer (old bearings) under the jamb nuts. So far, so good.

[chevy45412001]

good deal

i'll get back to you on the rotor size . i really don't get on here as much as i'd like to any more,but i am trying to fix that.

[bikerphil]

Thanks dude. Got the headlight bucket mounted up, ign switch, and the bars and controls are on. Waiting on my 17mm Kawi axle to show up. The FJ fork legs will be modified to take a 17mm axle, rather than it's usual 15mm. Gotta work on the guage cluster next, should be no problem. Couple more pics...

[Cobia]

Looking good Phil. How do those bars feel when you're in the riding position?
Do those forks have the same travel length as the ones you took off? The look shorter.

[bikerphil]

The bars feel like I'm ready to ride over 100 MPH, lol. They are up about an inch higher than clip on's on XS forks would be. I'll lose about an inch of fork travel. Still waiting on my axle and some 6061 aluminium for the caliper brackets.

[bikerphil]

Well, got the wheel bolted up with a Ninja axle, and the original wheel and rotors. Took her out for her maiden voyage, and I have to say she rides 100% better than she EVER has. She soaks up the small bumps in the road just like they're not even there. I haven't even fine tuned the damping settings yet or changed the fork oil. That is one thing that has always bothered me about the stock suspension, it's inability to soak up small bumps and ripples in the road. No front brakes or turn signals yet, but I'll start working on those mods tomorrow. More to come later, including lots of pics.

[Cobia]

Don't forget to change your signature now!!!! He, He!!