Late T140 M/Cyl

Has anybody fitted the late T140 front M/Cyl to their MK3? the S/S ones are 13mm bore so a direct replacement. i have just got a MK3 after yrs of Tridents and the front brake seems a bit weak, i have read plenty of posts and done a search but cannot find any specific info
Thoughts appreciated

Tripler said:

i have read plenty of posts and done a search but cannot find any specific info

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Did you know there is a 13mm master cylinder assembly available for the Mk3?

Andover Norton do a matt or gloss 13mm m/cyl for Mk3

thanks, but they are nearly twice the price of the T140 item

a bit of background, my bike is fitted with early version of the RGM reline, but i am struggling to get it set up right. the PO had used a small set screw as the piston pusher. i have purchased an adjustable pusher from RGM but struggling to fine the sweet spot where it works?

Tripler said:

a bit of background, my bike is fitted with early version of the RGM reline, but i am struggling to get it set up right. the PO had used a small set screw as the piston pusher. i have purchased an adjustable pusher from RGM but struggling to fine the sweet spot where it works?

Click to expand...

Take off the cap and the rubber seal and maybe the fluid, you can now see the 2 holes. As you operate the lever look at the hole nearest the centre. The seal will move under the hole moving right to left, with the brake off you want the seal to have just moved to the right of the hole and just be hidden. This will give the route for the built up pressure to release back into the reservoir when the brake is released and that occurs in hot weather as the body heats up and the seal seems to move blocking the hole off.

Tripler said:

i have purchased an adjustable pusher from RGM but struggling to fine the sweet spot where it works?

Click to expand...

The piston pusher should be used to set the fully retracted position of the piston and adjusted so that it just uncovers the bleed port when the piston is fully retracted as kommando said, and care should be taken not to over-adjust the pusher so the retracted piston seal does not uncover the bleed port or pressure can't vent from the system causing the brake to drag or even to lock on suddenly without warning. If under adjusted then there will be excessive lever travel before the brake begins to work.

kommando said:

Take off the cap and the rubber seal and maybe the fluid, you can now see the 2 holes. As you operate the lever look at the hole nearest the centre. The seal will move under the hole moving right to left, with the brake off you want the seal to have just moved to the right of the hole and just be hidden.

Click to expand...

However, the bleed port drilling is too small to see the piston seal and one of the drillings in the sleeve won't necessarily align with the reservoir port (actually the drillings for both ports).



The way to tell if the piston is set correctly is by the spurt of fluid as mentioned in the RGM instructions.
The RGM instructions now say the master cylinder should be bled before (and with a temporary bleed nipple now supplied fitted in place of the brake line) it is fitted to the handlebar.
"Once bled up, ie no more air enters the reservoir and lever is firm, a small column of fluid should be seen entering
the reservoir as the lever is pulled in.
11. The master cylinder can now be fitted,...etc."

Getting back to the original question then, as far as I'm aware, the screw positions of the late Triumph master cylinder should be the same as the Mk3.

Thanks both, great info . I am off to the garage

Followed the advice and the brake seems much better now just need to bed the pads n new disc in. hopefully get a first run out on the bike tomorrow .