Hi guys,

I put my new 04 CBR600RR calipers on yesterday and started bleeding them, ran about 250ml of fluid through the lines, until no more air was coming out, but still had no pressure behind the lever. I then tried reverse bleeding the lines, again the same thing, no pressure behind the lever.

Tried another few methods of bleeding, but still couldn't get any pressure behind it. It's still the stock RVF master cylinder (that had been rebuilt only about 4-5 months ago) and running HEL braided lines. The system was working fine until I put the CBR calipers on yesterday.

I also put the stock calipers back on and tried bleeding it and it worked fine.

Oh, I also noticed that while I was bleeding it, if I opened the bleed nipple without any pressure on the lever, it would suck everything that was in my bleed line back into the calipers, not exactly sure where the back pressure is coming from though.

Anyone have any ideas what it might be?

make sure your M/C is primed and move pistons out a bit in the calipers, if pushed all the way back sometimes fliud can/t get behind them.

Sounds like a big air lock in the calipers. Try pre-filling them before fitting the lines.