Hi,
Its a bit strange but in Haynes manual XTX and XTR MC are same 12,7mm.

If you have XTR caliper and XTR MC then I personally think changing just disc size from 298 to 320mm should not make any need to change also MC. Friend of mine changed front disc size on yz250 and he was quite happy with performance and did not have to change anything else.
Maybe piston seals in caliper might be worn so they are not moving so good.

If you have time you can try another MC from that CBR but it will be around size of Tenere MC because CBR had 2x 4 piston caliper.

Anyway you will be wiser at the end of day :)

Falcon1651, your last sentence is why I�m building this bike:

http://i1382.photobucket.com/albums/...psmgg4fjh5.jpg

Sometimes a pain in the ass, but when it works...:yahoo:

[QUOTE=Falcon1651;213546]Hi,
Its a bit strange but in Haynes manual XTX and XTR MC are same 12,7mm.
/QUOTE]

Also strange on a jap bike is 12.7mm is 1/2"... like they
converted it to metric....

my XTR has the XTR MC & a CR250 2 piston caliper
and a 320mm disc....
works just fine....

Ernesto, it looks really cool :023:

Have you done any mods also inside the fork like change valving/springs etc?

Yes, the fork was very stiff. At first I only changed the springs,seals, sliders...When I ride fast or in a jump everything was ok, but for everyday use I feel every pothole in the road. Too harsh.

I spoke to a motocross suspension specialist and made a set up similar to a supermotard. Now is OK for me.

I�m thinking of opening a new thread for my bike, to explain what I did and to ask for advice and help because much remains to finish.

Exactly Ernesto, I think that I need to do the same - change inside settings to supermotard because the ride is really not so comfortable as it was with original forks and I expect from 300mm front fork to be comfortable :)
It would be really good to know what you did to the fork.
I will also make some build thread of my bike when I will have some free time.

I took my fork to a motocross suspension specialist that put 0.54 springs, because are the stiffer you can get to the 09 Kayaba, but due to the weight of the XT you�ll need 0.56 or 0.58, also 5W oil and SM revalving.
With the revalving and the 5W oil the harsh feel dissapeared.

I have Showa USD units in mine...
The travel has been shortened down
from 300mm to 240mm to keep the
bash plate off the ground under full
compression...
valving was changed from MX to enduro
set up..
springs are from a Kawasaki shortened
to fit...
Offroad it's great.. but still a bit soft on the road
it can wollow a bit in the corners at times..
a bit soft not qute enough damping... might
try a heavyer oil .. has motul light 15cst need
a oil with 18 or 24cst rating... motul med or heavy..
Guess yer can't have both...


pete


..

Five days ago I changed the front brake pads trying to improve the feeling and it works.

It still doesn�t have much power, but I can feel what the brake is doing and it feels more progressive than before.

Old pads were EBC HH with 35.000km, I bought the new ones in the local shop, I wanted just normal pads and the shop assistant gave me a cheap SBS pair, that ended up being HH too. I wanted no HH pads just in case the HH compound is more race oriented and the initial bite is better for normal pads, but this SBS works well for now.

Anyway this week I will try the 5/8 MC.

Ernesto, when I searched all forums about increasing power of original front brake for YZ fork I found out that the best pads you can get in YZ/WR Nissin front brake are original pads from Honda. They are the same shape/size as Yamaha since they have the same brake caliper. But I have not chance to test this by myself.