XJR400 Front Ends

[Mike Shelby]

Hi - Does anyone know if there were any differences in the size of headstock bearings between 1993 to 1997?

The reason I ask is I've managed to get some decent front forks with new seals just been done (as mine are pitted), replacement top and bottom yokes - but didn't know till they arrived they are from a later XJR - mine is a 1993 or 1994 4HM (without brembo calipers) but the replacement forks I have are from a later one and the caliper mounts are 100mm apart instead of 83mm apart like mine is at the moment.

I need to put the replacement bottom yoke on as I have one of the four bolts sheared off inside the current yoke and no way of getting it out - hence replacing the yoke with the new one and it would make sense to change the old roller bearings for tapered ones while I'm at it.

If I use the new forks I have I'll have to get alternative calipers for it and it 'visually' looks like R6 (5eb) bluespot ones would fit but unsure where the pads would sit in relation to the front discs on an xjr400. Another alternative would be to strip both pairs of forks and put the new unpitted chrome tubes in my original lowers - would this be easy to do as I'm not too sure how and what's involved in taking forks apart. Doing it this way would mean I could re-use my existing calipers (although they aren't by any means the best brakes I've ever used but would be a cheaper option than buying replacements).

Any thoughts, info or help would be appreciated

[Evilchicken0]

I can't answer the geometry question about the lower yoke but most of the FZR front ends can be swapped in or out. You might a Yamaha page that gives the two models offset, rake and trail but I doubt they'd be too different without the model's styling being changed.

100mm caliper mounts is good for the "Bluespot" calipers. You cann get silver spot too, which were on the Fazers and sometimes a little cheaper. There's Gold spots on later sport bikes, they have titainum pistons and ceramic coating. They'll fit and be fine for your disks, I think Yamaha move the mounts rather than have new calipers made. Check the later bike uses the same dia disks as your bike (probably 298mm)

[Kayla850]

Are the yokes the same pitch?

The wheels and discs are the same across the models so if the yokes are the same pitch you will be ok to use gold/blue/silver spots on your new (100mm mount) forks.

The 83mm and 100mm calipers have the pad centres offset by 2.5mm relative to the fork mounting faces (which is why you can't just whang a set of blue spots onto a pair of 3TJ forks without machining them down or using offset brackets- mounting centres notwithstanding)

It's more difficult to explain than see what I mean- if you have the parts assembled in front of you it'll make more sense!