Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > Monsters > Replacing master cylinders

[Dave G]

I'm about to replace the brakes on my S2R with standard Ducati/brembo goldlines and have all the parts to do it waiting in my garage.
This made me realise that to get a balanced look across the bars I'll need to replace the clutch lever and therefore the clutch master cylinder too with one from -say a superbike or similar.
Can I just remove the existing boxy one and put a new one one on ?,I know the bore of the cylinder is important but dont know why,can anyone tell me why its important and what difference it will make?,and is it actually the same size internally?
What may be the pitfalls?,it appears to be a simple bolt on job with bleeding the system being the fussy bit,can I keep my existing hoses?
And has anyone else done this?

[Derek]

Dave,

You can just replace the monster m/cyl with a superbike and i's remote reservoir. A friend with an early SS which uses the same boxy masters as the monsters did just that.
The only difficult bit is bleeding the clutch line which can be a real PIA until you know how. Once you've got fluid coming throught the slave bleed nipple and all the air is apparently out, you will probably find that you still have no pressure to lift the clutch. Two things you need to do.
Purge the slave cylinder by unbolting it, loosening the bleed nipple, pushing the piston all the way in, tightening the nipple again then releasing the piston. This will purge any air out of the slave cylinder. Don't squeeze the levet while the piston is unbolted or the piston will pop out and you will have to start over again!
The other thing is to get rid of the air which gets trapped at the M/Cyl banjo bolt. Either loosen the banjo, wrap a rag around it and pull in the lever, tighten the banjo then release the lever (this can be messy if you are not careful, watch out for the paintwork!) OR tilt the bike to the right and jiggle the lever until all the bubbles stop coming out of the wee hole at the bottom of the reservoir OR (perhaps easier that tilting the bike) remove the cylinder from the handlebar and hold it so that the banjo is lower than the reservoir and jiggle the lever as above.

[Dave G]

Thanks Derek.That actually sounds a bit more straightforward than I thought-a straight bolt on job,fantastic!
I always knew the bleeding of hydraulics systems would be a pain but if that seems the fiddly bit then I'll be quite pleased.
Now all I need to do is source a clutch bar assembly without costing a fortune and I'll be sorted.