f4i brakes
Thread Starter
stunt rider
Joined: Sep 2009
Posts: 61
From: Bakersfield, CA, USA
f4i brakes
So im trying to figure out what the hell is going on with the front brakes on my f4i. I am trying to bleed them but the lever wont harden up. I've blead brake systems a thousand times and I've never seen this. I know the master is good because I changed it out and used a working one fresh off of my other stunt bike, and the capilers aren't leaking and have good pads. The lines are steel and also have no leaks. I tried gravity bleading from both the master cylinder and the calipers for a few hours, used a vaccum pump for another probably 4 hours, and also the syringe but for only about an hour. I have been without front brakes for over a month now and I am completely out of ideas. I keep going back to it now and then and try more hopeing that they will firm up but I am always disappointed. The best I got it you can still push the bike with the lever all the way in, but it does have a little resistance. What do I do??
also known as OMR
Joined: Jul 2006
Posts: 79,288
From: OMR INDUSTRIES in west palm beach florida
Re: f4i brakes
this may help too 
I don't know if its has only happend to me, but I feel this is why I have herd so many bad stories about people not able to bleed Radial MC's. so heres how you fix them.
1: How to find out if your radial has this problem is simple, dis connect the reservoir and brake lines then drain it of all brake fluid.
only thing u need attached to the MC is the reservoir hose and lever.
Make sure your bleed screw is tight and now either attach an old front stock brake line to it or put your lips against the master when the banjo bolt goes and blow into it. listen for the air to blow out of the reservoir hose, if u can't hear it then most likely you can blow any pressure through the line/banjo bolt hole.
2: So now you have diagnosed that your mc is not allowing reservoir feed.
3: And here is the fix, take your lever off the MC and then put it back on, notice that you have to put pressure on the rod that pushes the piston into the mc... now that the lever is off u can blow pressure through the banjo bolt hole, simple fix is to grind away little by little to the end of the rod that goes into the lever that actuates the piston in the MC till u can slide the lever retaining bolt through the MC with out compressing the piston., here is a picture of the rod u need to short lightly.
https://www.stuntlife.com/forums/att...-hbs-brake.jpg
1: How to find out if your radial has this problem is simple, dis connect the reservoir and brake lines then drain it of all brake fluid.
only thing u need attached to the MC is the reservoir hose and lever.
Make sure your bleed screw is tight and now either attach an old front stock brake line to it or put your lips against the master when the banjo bolt goes and blow into it. listen for the air to blow out of the reservoir hose, if u can't hear it then most likely you can blow any pressure through the line/banjo bolt hole.
2: So now you have diagnosed that your mc is not allowing reservoir feed.
3: And here is the fix, take your lever off the MC and then put it back on, notice that you have to put pressure on the rod that pushes the piston into the mc... now that the lever is off u can blow pressure through the banjo bolt hole, simple fix is to grind away little by little to the end of the rod that goes into the lever that actuates the piston in the MC till u can slide the lever retaining bolt through the MC with out compressing the piston., here is a picture of the rod u need to short lightly.
https://www.stuntlife.com/forums/att...-hbs-brake.jpg
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