loss of fr brake pressure

First off do not use pure synthetic brake fluid. Pure is DOT 5, not 3/4. 5 is great in a show vehicle that does not run or HD motorcycles. It does not absorb water, so when you get water in the system it puddles. It is also very hard to get in the system without foaming it and also very hard to bleed it.

Probably the best stuff you can find on the local shelves of most autopart stores is the castrol LMA fluid. You can also go to an auto dealer and ask for some HD racing brake fluid which will be a high temp3. Ford has some great stuff.

Back to the issue, it sounds like the MC is air locked. DId you run the MC reservior dry when doing this? If so, that is the problem. The best way I have found to get air out of the front MC on bikes is to grab the brake lever pull it in and just let it go. The slapping against the stop there gives enough vibration to help move the air bubbles out of the MC bore. I had to do that for about an hour when I swapped my front brake line over to SS on the XR600. The KDX was much easier to bleed. Alternatively you can dismount the MC from the handlebars and put that lower than the front caliper and bleed that way. Air will want to travel up in the lines.

If all else fails, my general rule is to let the system sit for a night. That will allow all the air to puddle in one place, take another stab at it the next day and you can usually finish bleeding the system.

The only way I can bleed a front brake is to take the whole the system off the bike and hang it vertically in the garage somewhere for a couple days with the caliper up.

Whenever you get a chance tap on the master cylinder, brake line, and caliper with a screwdriver handle or what not.

After a couple days of this your air bubbles will be near or in the caliper . Now bleed the brake normally but still in an inclined position. An old set of handlebars comes in handy here. Pump the lever a few times, hold it, have somebody open and close the bleeder quickly. Keep the brake lever in until the bleeder in closed. Repeat several times until you get a firm feeling.

DOT 3/4 is fine. Certainly never put 5 in with either.

Keyword(s) here is vacuum bleeder. Don't cost much.

Blew out the brakeline with compressed air? Hhhmmm...I sure wouldn't recommend THAT, ever! Chances of your air being dry are about nil. In carolina, even! Does it ever get under 105% relative humidty east of denver?

You have to keep 'resetting' the diaphragm on the MC cover. Do the pump-'n-bleed thing a couple of times, take the cap off to refill with fluid and reset the diaphragm.

Here is a link for some good info on brake fluids:

http://www.shotimes.com/SHO3brakefluid.html

I unfortunately know what you're going through. Did my front brakes last fall and for days I couldn't get any pressure to the brake. Finally, through this forum, someone recommended injecting brake fluid (DOT 3 or 4 is good) from the caliper UP to the master cylinder. Basically, you get a small syringe, fill it with fluid, pop on a short 3 inch plastic hose from the syringe to the caliper and inject so you overfow the caster cylinder. Do that about 5-6 times -- bubbles gone, pressure back. Good luck!