After having been off the road since 5th of May. Having pulled the slave off twice. Having stripped and rebuilt the master 6 times. Having read countless articles and viewed dozens of You tube clips on bleeding clutches and brakes. Having endured countless barbs from my Harley riding mates. Having sought out and consulted every bike guru I could find. Having cursed every god known to man and invented new ones just so I could curse them too I did it. At 4:30 today I finally bled that damn clutch.
And the frustrating thing is I have no idea why this time out of all of the hundreds of times I tried, it worked.
I tried manual bleeding, vacuum bleeding and reverse pressure bleeding, fast bleeding, slow bleeding, bleeding with the engine running, bleeding with the bike laid over. I tapped and downright bashed every part of the system I could reach to dislodge bubbles, tied the handle down, let it stand for a week, let it stand for a week with the handle tied down.
Up until this morning I had spent more than twenty fruitless hours over three weekends trying to get the system bled. And today was D day. Such was my level of frustration with this stinking bike that if it didn't bleed today I was going to sell it. Indeed if I had won lotto at any time in the last week my first action would have been to put the bloody thing through the car shredder at Hexham.
I had some advice last night which saved the day.
Try as I might I could not get pressure up, the handle would feel vaguely hard but nothing more which lead me to suspect the seals were bypassing. (Ok all you guys with dirty minds I get what I just wrote!) The bore of the cylinder was like a mirror no scoring to worry about. The seals were fine and not nicked.
I had been using clean brake fluid to lubricate the seals. A guy on some forum somewhere said this is often not good enough. He suggested assembling the master cylinder using PBR Red grease which ironically is blue. At the same time I decided to prime the master cylinder before I reattached the line because I read that somewhere too.
Bingo, it worked first time......Pressure up.... for five pulls and then nothing. I continued bleeding for another hour without a single bubble coming out but still no pressure so I pulled the master cylinder apart again repeated the process and bingo pressure up again....for five pulls and then nothing. I bled for another hour still no bubbles so I pulled the master cylinder apart for the third time today and I examined everything with a magnifying glass. There was nothing I could see which would cause the problem so I went inside for a late lunch and wrote the add to sell the bike.
The bike must have figured out I was serious because when I reassembled the master cylinder and primed it. The pressure came up and stayed up. Why it did that time I have no idea. Theoretically there should be a bubble of air in the banjo bolt but the pressure stayed up. I went for a 40 kay ride and the pressure stayed up with no sign of the previously slipping clutch.
So what I have learned. (In addition to the stuff I posted before)
There is a small bleed hole which is is positioned in between the two seals. It's function is to modulate the return stroke of the clutch. If you let your system get full of crap little pieces of it float up and potentially block that hole. The pressure can't escape so the clutch gets held on and slips. I was scrupulously clean when I rebuilt the cylinder the first time but as a bike guru pointed out the lines are still full of crap so as you work the clutch little pieces of crap find their way back into the master cylinder.
My bike was fine for about forty kays and then one of these pieces obviously blocked the port and the clutch starting slipping. Bike guru had the same problem on a Blackbird and kept a piece of fuse wire to unblock the hole. The only way to ensure the problem is completely gone is to replace the lines.
If you can't get pressure up suspect a bubble of air is trapped in the master cylinder. Even if you are not getting any bubbles out suspect the master cylinder and prime it. It worked three times for me.
Use PBR Red grease when you reassemble the master cylinder.
I probably know heaps of other stuff which I can't remember so if you are having problems I would be happy share what I know.
Maybe now I can get some riding done!!!