A frustrating weekend!

[metalcatfish]

OK, spent the entire weekend working on the cb550. I dont normally spend so much time on her but I have let the rot set in a bit the last year or so, and havnt invested any money at all for a lot longer. Its starting to show.
She has a couple of bad oil leaks from the oil pump and gear change oil seal. Not normally a problem but it is covering the chain and hence my back wheel in oil. (better than a scottoiler though!).
I have a new rear tyre on order so decided to tackle at least one leak. So had a go at the oil pump, by far the easier to fix. Ok no problem so far. Cleaned air filters, plugs, checked cam chain, valve clearances and timing. Changed oil. Started on the front brake system, It squeeled really bad.
Thats where it all went wrong.
Ive poured about 2 litres of brake fluid through my master cylinder and all I get is sponge! Its a relatively new piston so ive cleaned that and reused it. Fluid seal was replaced. Normally, when I get this much pudding in a front brake I suspect the piston seizing. But its good and moves freely. I can only suspect the master cylinder has decided to lay down. It is original and never been serviced.
Ordered new pads, Master cylinder assembly and bleed nipple.
Then, as im wheeling the damn thing off the drive to bed the pads in, one of the carbs starts gushing petrol! Lovely.
Its beer time now.
Cheers

[kaceyk2]

It never rains but it pours eh?
Sometimes, when completely changing the brake fluid, it cant be helped to get a spongy feeling as the act of pouring the fluid and flushing it through has picked up air, this can be made worse by going out and buying a new tin of fluid then carrying it home in the boot of a car or a top box on a bike and shaking it up all the way home...aireating it nicely.
Sometimes, all it needs is leaving over night for all the air bubbles to rise in your bikes brake system.
Check it in the morning before sending off for parts just in case.
Also, for air to get into the system from outside...fluid has to get out, so you should see a weep if thats the case.  First suspect would be to peel back the rubber on your master and have a look, giving the lever a really good tight squeeze like you were anchoring on like hell. If it's bone dry there, then check all unions down to the slave on the wheel caliper, no fluid getting out=no air getting in.
Give the carb in question a tap with the plastic handle of a screwdriver on the float bowl, I bet its just a sticking float...did you have her on the sidestand whilst working on her?