Hi All,

Purchased a bike with a springer front end, the guy/shop that did the work threw on a 4pot Brembo front caliper off an older ducati.

The brake lever is hard as a rock, taking a stab at it i'm guessing that the (standard?) master cylinder doesnt have the leverage to push the required amount of fluid to move the caliper pistons? What are my options for getting some brake feel back?

 

good to know the master is correctly sized, thanks. I will pull the calliper off and sus out if the pistons are moving freely. And will remove the brake reservoir cover and see what I can see. Are there any common faults with the master I can identify or things to look for?

But what size is your master cylinder ?
The size should be cast into the housing

Sportster Standard are 1/2 . Soft Tail 9/16, Bikes with Twin Disc 11/16 or 5/8

no marking on the master cylinder, but the bike is a sportster so unless anyone can say different I assume that what they are? and 1/2 wont have enough balls to push a 4pot?

Pulled the calliper off turns out its a 11/16 so it's pushing a little too much fluid for my liking so will have to scale it back, anyone want to swap for a 9/16?

That's what I expected.
I doubt a new m/c would be that expensive.

well just to throw spanner in the works I have almost the same caliper brembo 4spot with 5/8 master and works fine in the shed bike
has not been riddin yet and that caliper is going to be a pain to bleed its upside down bleed nipple should be at the top
I don't think there is a problem with master buy the sounds of it , do what has been said line off any fluid/open nipple
does leaver move than ? sounds as if caliper is seized

yep that's one thing you want to know that the caliper has fluid there and master has free movment and than if it does start looking at the caliper

Dude this has probably already been stated but I'm just trying to accumulate posts. With the calliper changed you are now compensating for the difference with your hand through mechanical advantage i.e. the brake lever. generally smaller master/calliper ratios give better force but slower response. And higher ratios give quicker response but less force. Having said all this though it does not add up because if you have changed to a 4 pot, your brake should be lighter, not heavier. 4 pot calipers tend to feel "harder' because you have more direct effect on the master. Does the brake work well? if so then adjust your style to suit, if not then something is wrong.

Mind you though that brake looks tough.