Motorcycle Repair: 83 Honda Nighthawk - Clutch Bleeding, clutch slave cylinder, honda nighthawk

Question
Hello,

Here is the situation, I had to replace the oil seal that is behind the clutch slave cylinder on my 83 honda nighthawk. The procedure went fine and the seal was an easy fix. The problem now is that I cannot get the clutch bled, it feels like there is no pressure coming from the master cylinder, as I pump the clutch lever it does not seem to build up any pressure, I have been trying for a long time, basically pumping the lever and then holding it down as I crack open the bleeder on the slave cylinder, barely anything comes out. I began to think that the master cylinder was bad so I ordered the rebuild kit and installed it, but it is the same. Could you help me with another method or with what you might think is wrong. Any help would be great because I am at my wits end. Could the slave cylinder be bad? Or would that not make a difference.

Thanks!
Eric

Answer
Hi Eric.
They never mention some things in the repair manuals because they assume that everyone with a bike knows all the tricks.

Here's the part they don't tell you about the clutch/front brake;

Some bikes have an additional problem with both the clutch and front brakes, including my own.  The problem stems from the configuration of the master cylinder, which is that the connection to the hydraulic line at the master cylinder creates a pocket that air bubbles like to hide in (this is
called a reverse trap) and the method for bleeding that section is a little tricky if you've never done this before.

 Here's the proceedure;

1) Bleed the clutch/brake line like normal.

2) Put a wrench on the banjo fitting and squeeze the lever.


3) (NOTE: Use a box end wrench for this) While holding the clutch/brake lever in, crack loose the fitting and reclose it quickly. Have a rag over the fitting connection that you are working on because it will spit at you as pressure expells the air and a little fluid.
IMPORTANT NOTE: Do not release pressure on the lever till the fitting is tightened back up or you will suck air back into the line.

4) Test the clutch/brake again.  If done correctly, you will have pressure near the beginning of the lever movement rather than at the end.

5) Repeat as needed, but should not need more than 2-3 times.

Good luck.
FALCON