Another basket case project, but with potentially a different end goal!

Oh, and by the way.... ITS ALIVE!!!!



Still runs a little rough though.

White smoke from left exhaust. And when throttling, it first wants to die, then revs high and stays there before slowly coming down so I cant set the idle properly.... sticking needle pistons?

Also, the aftermarket temp gauge is leaking and it doesn't seem to be getting petrol through the petcock at a rate that I was expecting. Also, I might as well not have an exhaust as it is LOUD and still has a few holes before the collector box!

Paul

I'm liking the lines of that bike & it still sounds sweet even if it has got holes in the exhaust

McBoney wrote:
When trying to unplug the second hole it was really solid, so much so that it seems to have been plugged in purpose?? I think in order to open it up I need to drill it out, but before I do that, are you sure there should be two holes going from rear brake mc reservoir into the mc piston bore?

STOP ! Don't drill anything. The small 'hole' you see is a counter-bore. The hole your looking for is at the bottom of that counter-bore and is not much bigger than a guitar string. Poke around in there with a guitar string or the pointy end of a round wooden toothpick. It should take much more than that to clean it out.

Thank you.

But I'm afraid I'm still not clear on whether there are two holes or one - not counting the counter bore (btw, what is that, and what is it for)? If as I suspect there should only be one hole that goes from the reservoir into the bore, then I still don't see how one can reverse bleed as I cannot get anything past the piston seals. I may just put everything together and see if I can bleed it the conventional way.

I started her up again and less smoke this time - I think that may be WD40 that I sprayed into the carbs to loosen up the needle pistons - which are still sticking btw. It still sounds like it is not firing properly, but all cylinders have spark and all exhausts get hot evenly. Carbs definitely need tuning...



Water leak solved and petrol is running freely. Just carb tuning left and the brakes of course.

Front brake definitely has no air in, but there is no pressure in the system, not even poking it with a screwdriver instead of the handle.

Paul

There are two holes.

The bigger one is 'behind' the piston and is the primary port for replacement fluid in the circuit as the pads wear (of course, fluid can also get into the circuit through the second, smaller hole too).

The smaller hole is as discussed above and is at the bottom of the counter bore and located in front of the piston. In your photo, the counter-bore looks like it's the same size as the main port so I can't tell which port is which but the one that appears plugged will be the small one.

I suspect a counter bore is used because the small hole is too small to cast successfully - casting in a counter-bore provides a convenient locating point for machining the small hole.

If you're right about no air being in the system (and I bet you're wrong about that) the only other explanation is there's something wrong withe the master cylinder. I suppose there could be something wrong at the caliper end too - like a massive leak - but I assume that would be quickly noticed.

Ok, I’ll have a closer look now I know what I’m looking for. I have guitar string that I’ll use to see if I can free up the smaller hole.

You may well be right about air in the front brakes but I’m blown if I can find it. I have bled it through twice now (the conventional way). The banjos are dimpled. The mc seems to pump fluid ok when bleeding and there are no fluid leaks anywhere...

---

Additional: Result! You were right, in the centre of the second hole, there was a very much smaller hole and that was blocked.



I unblocked it with some thin wire and put the MC back together. I put it on the bike and can now blow from the rear caliper through to the reservoir, so tomorrow I will reverse bleed the rear brake system.

You can just see the thin wire poking out into the bore.



I'll do some googling on how to bleed Brembo Gold series calipers... maybe there is a particular trick on these that I am missing, and I have emailed Oz to help me with the sticking carbs.