R1 Front Fork Conversion

[bama1]

Has anybody done a R1 fork conversion?If anybody has how much work was involved. Thanks Buddy

[Rich Pleines]

If you are not aware of this link it may be of interest

http://www.fjmods.btinternet.co.uk/

[fj1289]

Buddy,

I've done 3 of these.  I think it is a good way to upgrade the front, but there are a few issues to sort out.

First, if you use the front rim from a YZF1000 (ThunderAce), you can keep the stock speedometer setup.  The YZF1000 is the only rim I know of that used the R1 style brakes and still retained a speedo drive.  You do have to remove 8mm (If I remember correctly!) from the inside of the left fork leg to make room for the speedo drive (there is a cast portion of the leg (like a built in spacer) that is easily machined off without weakening anything at all). 

Second issue is the steering stem.  The R1 stem is WAY TOO SHORT (and the diameters are wrong too) to be used in the FJ steering neck.  Yamaha also made the base of the R1 steering stem just slightly larger in diameter than the FJ stem.  You can press the FJ stem out of the FJ yoke and use it in the R1 triple clamps, but it is a loose fit.  You can have a new stem made at a machine shop (just a little shorter than the FJ stem and with the R1 bottom diameter), use the FJ stem and use a locktite product made for bearing races (I think), or you can drill and "pin" it in place.  New stem is the best solution, but also the most expensive. 

You will still need to put heavier springs in the forks, and probably use 15 wt fork oil to up the damping rates some. 

The fork legs are shorter than FJ legs.  But, some of this distance is made up by mounting the legs flush with the top triple clamp and adapting a set of "superbike" bars.

Also had to cut and grind a bit on the top clamp to get the FJ ignition switch to mate up. 

The offset of the early R1 triple clamps is the same as the FJ (35mm).  02-03 triples are only 25mm offset (great for drag racing or if you really want to jack up the rear end and steepen the steering angle - the less offset will give you more trail) There were also a couple of years with 30mm offset...

Good luck, ask any more questions you have - and if I thionk of anything else I'll add to it. 

Chris