Basic Maintenance: Brake Fluid

[Gone in 60]

One thing the Royal Enfield 650 is famous for is frequently having to bleed the rear brake. There was a recall on rear calipers for people who live in wet environments with calipers that tend to corrode, but living in a dry area and never really getting my bike wet, I haven't thought about that much. But, when mine sat for four months, I found that the rear brake was totally shot the first time I rode it. Air had entered the system and the pedal sank all the way with no pad movement. Only took a few minutes to bleed it and a lot of air came out. Since it's been such a widespread problem, the pundits on the RE forums have been talking about it. One of the current thoughts is that overtightening of the bleed screw when snugging it down after a bleed procedure might be allowing air to enter. Very interesting thought, one I had never considered.

On the BMWs, I have a GS-911 tool that connects to the bike's diagnostic port and can mimic all of the regular dealer service functions. When bleeding brakes, one part of the job is an "ABS bleed-down", which cycles the ABS pump a few times to release any trapped air, then you bleed a second time to release anything that came out of the pump. I've never heard of this procedure being specified in either Honda or Enfield service manuals for brake bleeding. It might just be BMW's overly-German maintenance process.

As for flushing and bleeding the clutch fluid on the CB1100, I do it every time I flush and bleed the brakes (every two years). I've already got the fluid, rags, tools and floor cardboard out, so it's a good time to get it done. Plus, if I've already opened a bottle of brake fluid, I want to do everything I need to do with it, as I'll probably toss what little is left in the bottle.