Yamaha TRX850 Enthusiasts Forum

How do.

I'm using YZF 6 pot calipers with an R6 master cylinder and lever set up on a YZF front end. Originally I was going to use R6 calipers, but then realised (duh!) that would mean relieving the **** out of the carrier, and that made me a wee bit nervous. So I got some YZF calipers instead.

Having ridden a few miles on the YZF front end (fresh pads, full m/c with new fluid), the lever is now coming back very far. No pulsing that I can detect, the brake feel is good and I can still stop hard under road conditions but it appears to be inching closer to trapping my throttle fingers under hard braking. I can get it to touch the bar on setting "1" on the adjuster.

Is this because the R6 m/c internal diameter (14mm iirc) is too small and isn't pushing enough fluid for the larger piston area?

If so, does anyone think the original TRX m/c (15.'n' mm iirc) will work, as I still have the whole original brake lever assembly, or will I need to track down a YZF or aftermarket m/c of a different size?

Thanks in advance...

I believe that the YZF m/c is the same bore as the TRX one (5/8") so you should be ok using the TRX one.

when you first pull the lever in and you feel the pressure in the line can you then pull it in a lot more ?? if so it may just need a master cylinder rebuild kit that's the piston , seals and spring they are about £25 for the rebuild kit

steve speed wrote:when you first pull the lever in and you feel the pressure in the line can you then pull it in a lot more ?? if so it may just need a master cylinder rebuild kit that's the piston , seals and spring they are about £25 for the rebuild kit

Not sure I'm getting the idea, but the lever feel is linear and there is pressure in the line. Good to know though!

I'll probably pop the TRX lever set back on this Saturday and see how that works.

Cheers...

Standard 5/8" TRX is what you need. 14mm is too small....

Kayla wrote:I believe that the YZF m/c is the same bore as the TRX one (5/8") so you should be ok using the TRX one.

Roger that, both are 5/8" = 15,875 mm.