Effects of Master Cylinder Size, Lever Length, ect.

[Biker Dash]

Ok, in my quest to make my bike the perfect bike for me, I have found I want some changes in the braking department. While the stock Vmax brakes seem to do the job just fine in most instances, I do know that they can be better.

With the front brakes, the pull feels lighter than what I would want, as well as feeling like there is more travel than I think needed for me. he current setup is stock in good condition as far as the lines and master cylinder and pads go. The fluid was fresh where as the brakes were redone with fresh fluid before I bought the bike last Spring. The front calipers might go for some cleaning, where as it has been rather dusty around here. (LOTS of road construction goin on in Maine this summer)

I was thinking about doing three upgrades to my front brakes. Premium HH pads, braided stainless lines, and a new master cylinder with a larger bore size. My question about the bore size is how will going with the larger bore effect braking, not only in performance, but in feel at the lever. I was thinking that the larger bore would make it so the force applied by my fingers would be more (heavier) but would require less travel to give the same braking effect as the stock cylinder? Is this assessment accurate? How well would this work when combined with the stainless lines and premium pads?

On to the rear brake. With this, I have found that even with the grippier Avon tire, it is still very quick to lock up. I was wondering if maybe a shortened brake lever might help there, giving me less leverage when applying the brakes, making it so they would be less likely to lock up. an added bonus would be that the pad on the lever would be in a position I feel more comfortable with for my smaller feet. I was thinking maybe shortening the lever by 3/4-1". What would be the effects of doing such a mod? Would it actually work as I am thinking?

On a side note (but related, due to master cylinders) I have read in another thread about going with a 14mm master cylinder in the clutch. This would make the clutch feel lighter, but I would also assume that it would mean more clutch lever travel. (Longer travel distance does not matter to me, when moving, my fingers pull the lever fully in as I am shifting) Would this have an added effect of increasing the length of the friction zone?

 

[MaxMidnight]

...was thinking about doing three upgrades to my front brakes.

1. Premium HH pads
2. Braided stainless lines
3. A new master cylinder with a larger bore size.

...how will going with the larger bore effect braking, not only in performance, but in feel at the lever.

How well would this work when combined with the stainless lines and premium pads?

On to the rear brake....it is still very quick to lock up. I was wondering if maybe a shortened brake lever might help.

...going with a 14mm master cylinder in the clutch. This would make the clutch feel lighter, but I would also assume that it would mean more clutch lever travel.
Would this have an added effect of increasing the length of the friction zone?

Have a look at this regarding lever ratio's.
Any change to the lever ratio will have an effect of the feel and effort needed to apply the brakes.
Whist increasing the M/C piston diameter will reduce lever movement you will also need to apply more pressure. The lever will feel more 'solid' and the brakes (to my hands at least) don't feel as efficient. Like most things in life when you make a change there are knock-on effects.

Rather than replace the M/C you could change the callipers. R1's, with no other changes would give the potential for more effective braking and by retaining the OE M/C you will have reduced the lever ratio.
Some folk get on well with this set-up, others prefer it with a smaller diameter M/C (myself included).
If you are feeling particularly flush then go the whole hog and get ISR radial M/c's (with adjustable lever ratio's) matched with their six pot callipers.

Regarding the rear. Shortening the lever will result in requiring more pressure on it for the same braking effort. However, the down side (seem to have been here before) is that force will require less movement thus you will loose some sensitivity and it will become more 'switch-like'. Only you will be able to tell if you are able to apply the rear brake with the required finesse. Levers are cheap to acquire so you won't loose much if it isn't to your taste.

Your assumption re the clutch is correct. You can mitigate the increased travel with span adjustable levers (or ISR's).
By the length of the friction zone do you mean do you mean the distance the lever moves from starting to take up drive to fully home?
In theory yes, but in practice I can't say that I notices any significant difference.

 

[Biker Dash]

Have a look at this regarding lever ratio's.
Any change to the lever ratio will have an effect of the feel and effort needed to apply the brakes.
Whist increasing the M/C piston diameter will reduce lever movement you will also need to apply more pressure. The lever will feel more 'solid' and the brakes (to my hands at least) don't feel as efficient. Like most things in life when you make a change there are knock-on effects.

Rather than replace the M/C you could change the callipers. R1's, with no other changes would give the potential for more effective braking and by retaining the OE M/C you will have reduced the lever ratio.
Some folk get on well with this set-up, others prefer it with a smaller diameter M/C (myself included).
If you are feeling particularly flush then go the whole hog and get ISR radial M/c's (with adjustable lever ratio's) matched with their six pot callipers.

Regarding the rear. Shortening the lever will result in requiring more pressure on it for the same braking effort. However, the down side (seem to have been here before) is that force will require less movement thus you will loose some sensitivity and it will become more 'switch-like'. Only you will be able to tell if you are able to apply the rear brake with the required finesse. Levers are cheap to acquire so you won't loose much if it isn't to your taste.

Your assumption re the clutch is correct. You can mitigate the increased travel with span adjustable levers (or ISR's).
By the length of the friction zone do you mean do you mean the distance the lever moves from starting to take up drive to fully home?
In theory yes, but in practice I can't say that I notices any significant difference.

Ok, maybe what I would need is a different rear master cylinder for the rear? I did get to thinking, and I think you are right about the finesse loss on the rear with the shorter lever.

As for the front, I want the more solid feel.
If I were to make changes, I would definitely want to keep the old hardware on hand, incase I need to go back.

On the clutch, you are correct in guessing what I meant. Plus, the lighter pull would be good in city traffic.