The glossy spots is wet satin hammerite. £60. Pistons look good and clean. Floating disc, HH disc pads and 14mm master cylinder repair kit (for T595 M/C I have in the shed) in the post.
After 2 days of reading ratio tables, playing with master cylinder calculators, finding formulas linking piston surface areas with just about everything else that moves on a vehicle I recon the ideal master cylinder is the 12.7mm bore for a 3 pot Nissen caliper. The optimum size may well be a bit less but given the sizes commonly available in the market (11mm, 12.7mm, 14mm, 16mm, 17mm etc) with suitable brake light switches, look, and a 'standard' lever length I'm going for a 12.7mm bore - basically the master cylinder for the 4 pot Brembo equiped gen2 LC 900 is the one. I'm expecting the lever to have slightly less travel and require a bit more effort than the standard braking system but close. And of course it's obvious. The 14mm bore supports twin disc, mostly 4 pot caliper fits. 11.7mm does the 2 pot gen1 single disc twins. The 3 pot Nissen has about 20% more piston surface area over the standard twin pot caliper. Working the maths a 12mm may be a ideal pairing but the maths is significant as there is so much to consider including disc size, weight of the machine, momentum etc.. Anywa, as a 12mm isn't available except for custom application such as bespoke racing kit it is the 12.7mm Triumph master cylinder. I got a second hand one tonight. Given I was going to use a 14mm, off a T595, master cylinder I had in the shed (free) is the whole endeavor worth it over buying a kit? Floating 310mm EBC Street Cup floating disc = £150 Used 3 pot Nissen Honda Caliper = £60 12.7mm used Triumph Master Cylinder = £85 Second hand but unopened EBC HH pads = £23 Total = £318 That, assuming all work well and the Master cylinder does not need a repair kit, gets you an upgraded braking system that is unlikely to stop you quicker (for want of a better expression) than the 4 pot brembo kit we all have seen. Is the Brenbo upgrade more reliable in the long term? Who knows? Will the kit look better? To me yes - it will all be new and unmarked and have Brembo written on it if that matters to you. As I write I'm undecided if I would do this again on any future bike. If I fit my solution and it bleeds up easy and works well it make my Triumph a bit more 'mine' and a bit more unique and have a more powerful front brake over standard. I guess I will be happy and forget the fact that I could have saved for another month or two and got a better solution. I will fit my solution next week now and post the 'on the road' assessment if anyone is interested.
Caliper on and 12.7mm (2022, 900 Bonnie) 1/2 inch marked master cylinder on. The mater cylinder is exactly the same except for the bore so mirrors, reservoir and brake swith all go on no problem. First bleed done - took some patience to get rid of the worse of the air pockets - but rain stopped play so I'm gonna bleed it again. Lever as expected. Very slightly firmer than standard. The old brake fluid was a little cloudy. I still have an ebc floating disc and new HH disc pads to go but so far so good. I have no centre stand so I'm gonna get an Abba stand or something to help me keep the bike solid so I can get the front wheel out safely. Photos to come once the job is completed.
