320mm front brake rotor question?

[joebloggs]

I've seen 320mm rotors available for the XJR1200, also fit FZR1000 and a few other models.

My 3CV has an XJR wheel with blue spot calipers, and there appears to be a fair bit of the pad that doesn't touch the stock disc.

So, will the 320mm disc fit or am I missing something?

My front wheel from another project, should stop the bugger.



92 16" Fireblade front wheel, Brembo 320mm discs for 98, Bremo P34 4 pad calipers.

[Pat Conlon]

320mm rotors will not work with your FJ fork legs. It's the lugs on the legs that determine where the caliper mounts and those lugs mount the caliper too low for clearance to a 320mm diameter rotor.
I don't recall ever seeing an adapter plate that will space out the caliper far enough to fit 320mm rotors. I suppose one could be made, I just have never seen one.

Of course, if you change your forks, you can run a 320mm rotor.

[joebloggs]

320mm rotors will not work with your FJ fork legs. It's the lugs on the legs that determine where the caliper mounts and those lugs mount the caliper too low for clearance to a 320mm diameter rotor.
I don't recall ever seeing an adapter plate that will space out the caliper far enough to fit 320mm rotors. I suppose one could be made, I just have never seen one.

Of course, if you change your forks, you can run a 320mm rotor.

I hear you re the caliper mount but there does seem to be about 10mm of space in the caliper beyond the outer edge of the disc.
I'm not suggesting you're wrong, just wondered if a larger disc would fit.

Almost anything is possible with a lot of searching and scratching of heads, Honda, Yamaha and Kawasaki made this front end, and the only machining was new wheel spacers, changed a few bits to come up with the Brembo's seen in the first picture, but I'm not afraid to give it a go, if of course its physicaly possible

[joebloggs]

320mm rotors will not work with your FJ fork legs. It's the lugs on the legs that determine where the caliper mounts and those lugs mount the caliper too low for clearance to a 320mm diameter rotor.
I don't recall ever seeing an adapter plate that will space out the caliper far enough to fit 320mm rotors. I suppose one could be made, I just have never seen one.

Of course, if you change your forks, you can run a 320mm rotor.

Oh
Forgot to mention I have a set of 00 YZF600 forks complete with wheel etc sitting in my shed, these may have to go on so the who;e question will then be irrelevant 

[Pat Conlon]

.....there does seem to be about 10mm of space in the caliper beyond the outer edge of the disc.

Our stock FJ rotors are 298-300mm diameter, I have also noticed the extra room you mentioned, which made me wonder about rotor expansion when hot. I wonder how much they could grow? 1 maybe 2mm before your brake fluid boils? I figure to be safe you would need an extra 5mm (~325mm) of clearance on a 320mm rotor to account for expansion.....just a WAG.

[joebloggs]

.....there does seem to be about 10mm of space in the caliper beyond the outer edge of the disc.

Our stock FJ rotors are 298-300mm diameter, I have also noticed the extra room you mentioned, which made me wonder about rotor expansion when hot. I wonder how much they could grow? 1 maybe 2mm before your brake fluid boils? I figure to be safe you would need an extra 5mm (~325mm) of clearance on a 320mm rotor to account for expansion.....just a WAG.

Maybe its the angle that the blue spot calipers sit at relative to the disc when fitted to the FJ fork legs.

In the picture above, with the white blade wheel, the Nissin calipers needed filing due to the caliper body fouling the disc when fitted to a ZZR fork. The caliper didn't sit square (round) to the circumference.

I will have a butchers from the opposite side in the morning and see if the gaps similar.