Thumb brake modification Yamaha R1

Modifying and fitting a Brembo thumb brake split system to the R1
Who is Comrod Motorsport:
/ @comrodmsport
To purchase Mity vac tooling visit:
gb.jbtools.com...
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To purchase brake fluid testing tooling visit:
www.zoro.co.uk...
To purchase split system adaptor visit:
racetorx.co.uk/
0:00 Intro
0:32 Why
2.00 Components
2.40 Mock up
03:26 Modifications
09:50 Clamp & lever install
10:45 Reservoir fitment
12:30 Hose fitment
15:20 Brake bleeding
18:40 Final test
20:00 Round up

[@sugars205]

Nice vid…. I guess I’m going to be out of pocket 500 quid!! This pay day!!

[@ComrodMsport]

Glad I could be of assistance…..can’t take it with you…..treat yourself 😁

[@vv6816]

Hi 👋 very good job 👍 I would like to ask you please how much long need be the steel brake line from the thumb brake until the back master cylinder ?

[@ComrodMsport]

Thanks 👍
This was a second hand kit from another bike so the line was already made, luckily it fitted. Was approx 850mm. If you measure what you need with string or similar, HEL will make you a hose to any length

[@vv6816]

@@ComrodMsportthanks man 🙏

[@kimabella613]

Have you ever thought of using a shuttle valve so you can avoid modifying the rear master cylinder?
i wonder if that will work.

[@ComrodMsport]

You mean like a brake bias valve?

[@kimabella613]

A shuttle valve ot double check valve,
Used to allow fluid to pass though it from two sources, 2 inlet 1 outlet. It has a moving shutter inside, if one of the inlet has the higher pressure will move the shutter shutting the opposite inlet and allowing its fluid to move.

[@kimabella613]

The idea is, using 2 brake master cylinder to 1 brake caliper.

[@kimabella613]

also i read that, it allows reverse flow during depressurise

[@ComrodMsport]

@@kimabella613 not something I’ve seen done but it sounds in theory like it will work. You would have to keep both master cylinder reservoirs though so more fluid to bleed/check/renew and you would potentially have more connections (failure points) in the plumbing 🤷‍♂️ maybe why it’s not common place

[@jonathanalvarezbrana9939]

👌👏👏👏

[@ibidu1]

ide love to know what brand that brake bracket is. I though about buying a cheap ali express left hand side master cylinder and trying to mod a kit up. Since quality thumb brakes are so pricy

[@ComrodMsport]

I have no idea of the brand as it was a second hand kit from a modified commuter bike but like you say, difficult to find hence the modifications to this one

[@motoguieb]

What do you call that thing that you replace from reservoir

[@ComrodMsport]

@@motoguieb if you mean in place of the original rear master cylinder, it is a thumb brake junction valve/splitter

[@391950]

What kind of master cylinder kit is that?

[@ComrodMsport]

It was a second hand unit from a commuter bike that had been converted so I’m not sure on the clamp hardware. The master cylinder is a Brembo unit

[@ianisas]

Seems kinda weak or am I bugging? You pressed it a ton to get the wheel to stop considering there's no 200kg bike to stop as well. Never had/used a thumb brake so I might be missing something.

[@togwilson]

I thought that too

[@ComrodMsport]

I get what you saying, though I wouldn’t say weak, more progressive to give you better feeling and finesse.
If you watch onboards of thumb brake use you’ll see they seem to get hammered quite aggressively and it’s for that reason. The super lightweight rear disc doesn’t help in that aspect either due to reduced surface area, it may be getting changed out in the future

[@ianisas]

@@ComrodMsport Thank you for the clarification

[@YoungboiiMakki]

Good✅️