Front Fork Setups

[cad600]

Yep, Modking made it for me. There are really only two ways to swap forks onto a FZR. You either swap the stearing stem from the FZR to the triple of what ever you are putting on. Or you do what George mentioned. If I had thought about or heard of George's method I probably would have tried that way. But since I didn't know about it, I went with the custom triple. There are too many things to think about with stem swap. Most people have had no issuse with either pressing the stem in or welding some material then pressing it in. Then there are the one's who have had issuses or start talking about engineering problems with it. I decided to bypass all the crap and do a sure thing fix.

[slayermd]

The fzr stem is dwarfed by newer stems. Bearings are very different. Vortex I think it is makes an fzr stem you could buy.

Hi,
some where on this forum I posted that stem swapping was not actually required, just stem removal. see the original post by Tony Foale (a leading euro-frame designer for sundry racers and now consultant to Segway ) who used a simple threaded rod and plugs to hold the bearings in their cups . which is after all the sole purpose of the stem !


QUOTE:-
Back when I had a business making chassis, we often had to adapt different
fork yokes and we also made our own magnesium yokes.  In all cases I did
away with a stem altogether and just fitted stubs into each yoke.  Tension on
the bearings was provided by a  rod threaded at each end, locked into the
lower yoke and which passed through a hole in the upper where it was
tightened with a nyloc nut.  The rods where either 10 or 8 mm dia. depending
on size of bike.  This simple and easy to make solution worked well and
saved some weight.

The added stiffness of a complete stem is quite minor when compared to the
alignment stiffness of the yokes clamped onto the fork tubes.

This subject has come up on the list before.  The late Hoyt didn't like the
idea but it worked fine in practice which is what engineering is about.

Regards

Tony Foale
info@tonyfoale.com
http://www.tonyfoale.com

(UNQUOTE)

Sorry George, Im a visual learner. This is what I got from that.


The green boxes are the fork tubes, the black lines are the triples, the red box is the frames head tube and the blue boxes are the rods.

Wouldn't the rods start to bend under high pressure? And how would that perform under a racing environment? Id like to know all the safety aspects of that because if it is a viable option, I wouldn't mind trying it out.

[Target30]

i am not understanding this, the stem sits inside the bearings, in the frame piec(dont know the name of it. with the above picture, how would it hold the bearings in place, and swivel on them? the bearings would have to be attached to the triples? i have a set of forks at home that i have to look at now, but i am confused.

[Target30]

ok, found a pic, and i kinda understand, but are the frame holes(where the fork stem goes through) the same on most of the bikes? cause the bearings would have to fit in there.

[slayermd]

ok, found a pic, and i kinda understand, but are the frame holes(where the fork stem goes through) the same on most of the bikes? cause the bearings would have to fit in there.

Post it! My little paint pic isnt all that great.

[haunter]

yeah I think a rod goes into where the stem went...

[cad600]

Basically, you put a rod where the stem goes. The rod has to be threaded at the top and bottom to take caps that screw into it that capture the triples and hold them in place. Think of it as adding a stem nut to the bottom of it just line the top.

[Target30]

dont mind the rust, is just from sitting in my garage, wipes right off! also, the whole setup is for sale if anyone needs it. came off my bike from last year, no leaks or anything, brake pads in good shape. yes, shameless.

[yamaha_george]

[


Sorry George, Im a visual learner. This is what I got from that.


The green boxes are the fork tubes, the black lines are the triples, the red box is the frames head tube and the blue boxes are the rods.

Wouldn't the rods start to bend under high pressure? And how would that perform under a racing environment? Id like to know all the safety aspects of that because if it is a viable option, I wouldn't mind trying it out.

Slayer,
sorry no the blue rod is in the center of the red box.

It is acting as the stem. The sole purpose of the stem is to posn & lock the bearings in place.
By using plugs & stubs as inserts in the bearings the rod can be tightened top & bottom until the bearings are seated and just able to spin.

I wrote Tony today to see if he has pictures of the arrangement in his history album some place.
If he sends details I will post.


Unfortunately with a broken wrist drawing out the idea and just typing out this is a real pain.
sorry

[yamaha_george]

ok, found a pic, and i kinda understand, but are the frame holes(where the fork stem goes through) the same on most of the bikes? cause the bearings would have to fit in there.

T,
the basic idea is you use what ever the frames original bearings were.
The bearing cups go in the frame top & bottom.
The bearing bits normallly fit snugly on the bottom triple tree and fit over the top of the tripletree under the fork top holder.

If you use a modern triple tree they are way longer than the FZR & are different sizes some times.

With Tony's idea you make a plug to fit the lower clamps where the stem used to be (or just cut the stem flush & fill that hole. ) make a plug for the inner diam of the top bearing & upperclamp.
drill ahole in the center of each plug to take a threaded rod 10mm diam well a nut to the bottom to act as a bolt head & use two locknuts at the top (the top nut should be an aero-style/ nyloc nut) adjust tension to suit bearings .just as you would with a normal stemmed bike.

The whole beauty of this idea is no fancy inter-metal welding , no need for a big press and working out accurate interferences so it will not prematurely bind on insertion or be loose when finished .

All the pieces are VERY easily made on a lathe (therfore cheap) fits in the bearing are close but not PRecision as such the rod can be any threaded rod of good quality mild steel if need be .(I prefer s/steel or tool steel )

[95FZR600]

George, can these be made for purchase? I know you would need to know actual forks used.....R6,R1 year whatever but it sounds easy.

Rob, why dont you give me yours since you dont ride your bike any how.

[slayermd]

Rob, why dont you give me yours since you dont ride your bike any how.

BURN!!!

[Marb]

the YZF750 and 91+ FZR 1000 USD's need the steering stem swapped and the steering bump stomps ground down and use the stock speedo

Sorry, but that isn't true.

The FZR400, FZR600 and the 91 FZR1000, all have the same bearing dimensions and nut dimensions.



From left to right: FZR400 stem, FZR600 stem, 91 FZR1000 stem.

Ik got a complete front end from a rear-ended FZR1000. This included, wheel, disks, clipons, triple tree, etc, etc.



The FZR400 and FZR600 dubbel piston brake calipers will fit on the 320mm disks and the forks. All i had to do was modify the steering stops om my 89 FZR400, but that was very easy. Just drilled a hole into the notch that is already there, theaded it, and added two bolts. Now ik have an adjustable steering stops.



Right the FZR400/600 wheel with 295mm disks, and left the FZR1000 front wheel with 320mm Disks.



Quite a difference.

The biggest difference was the stance of the bike, and how wel it handels in fast corners. Als braking (now you have a 120 tire) is amazing.

Everything just clears in the cockpit



The big advantage of the 320mm FZR1000 disks is that you can also mount Ducati/Aprillia Brembo disks.



All in all, including getting fresh bearings, replacing oil seals etc, etc it took me just under 2 days to do the entire swap.

[yamaha_george]

George, can these be made for purchase? I know you would need to know actual forks used.....R6,R1 year whatever but it sounds easy.

.

95,
It is easy & cheap (lathe work is the cheapest of skills to rent) once you have your measurements it is very quick.
Out of shear pig headedness I made a plug for the RD to take ducati triple trees and the plugs took me under 2 hours to make last night and that is with a bust left wrist

[haunter]

the YZF750 and 91+ FZR 1000 USD's need the steering stem swapped and the steering bump stomps ground down and use the stock speedo

Sorry, but that isn't true.

The FZR400, FZR600 and the 91 FZR1000, all have the same bearing dimensions and nut dimensions.



From left to right: FZR400 stem, FZR600 stem, 91 FZR1000 stem.

Ik got a complete front end from a rear-ended FZR1000. This included, wheel, disks, clipons, triple tree, etc, etc.


the ducati/aprillia brembo snowflakes area supposed to be a great upgrade, especially when you put the non-radial R1/R6 setups on them


The FZR400 and FZR600 dubbel piston brake calipers will fit on the 320mm disks and the forks. All i had to do was modify the steering stops om my 89 FZR400, but that was very easy. Just drilled a hole into the notch that is already there, theaded it, and added two bolts. Now ik have an adjustable steering stops.


Right the FZR400/600 wheel with 295mm disks, and left the FZR1000 front wheel with 320mm Disks.


Quite a difference.

The biggest difference was the stance of the bike, and how wel it handels in fast corners. Als braking (now you have a 120 tire) is amazing.

Everything just clears in the cockpit



The big advantage of the 320mm FZR1000 disks is that you can also mount Ducati/Aprillia Brembo disks.



All in all, including getting fresh bearings, replacing oil seals etc, etc it took me just under 2 days to do the entire swap.

thats impressive.

obviously, I hadnt done the work, I was going off what a few people that did some of the work told me.

Maybe the YZF front end I had is different, as its very similar to the 94+ USD's which are different from the 91-93's

but thats good info to have! that post needs to go to the wiki!