Rear hand brake

[mj2412]

Hi, on my electric offroad bike I'm using a standard Yamaha YZ rear brake. As a hand cylinder i tried first a KTM Magura hydraulic pump for the clutch. Unfortunately i have more or less no movement length at the lever. The pads are in slight touch all the time and the pump is very digital. Then i bought a Chinese scooter hand brake cylinder, but the behavior is still the same. I believe the piston is too big and the stroke to little. Now i'm thinking about using a formula left hand brake pump like the KTM freeride e. But this is quite expensive. Therefore, I want to ask for experience, before i buy this hand brake pump just for testing.

Any advise or other product is highly appreciated. Thanks.
Martin

 

[speedy1984]

I'm finger ready on the Formula here, happy it will bring the nose down when I'm ready.Buy cheap but twice

 

[DingusMcGee]

Martin,

Did you bleed the system of air?

 

[speedy1984]

Is this a trick question

 

[DingusMcGee]

Here is the cheap set I bought. The right side worked better than the OEM Kawasaki. The piston size is same for both sides. Clutch or brake on left — handle will drive either. I can lock the rear wheel with the left “clutch” unit.

See: 7/8" Motorcycle ATV Dirt Bike Hydraulic Clutch Lever Master Cylinder Brake Pump | eBay

Installed:

Kx100 x QS3000 V3 x Fardriver ND96350 x LiPo28s 20Ahr

The conversion is done. The Quandary was: The motorless motorcycle weights more than my QS3000 edirtbike build?? What will I get???? Motor choice? A QS1000, a QS3000 V3 and a QS4000 V3. The QS 4000 motor with sprockets aligned sat with right side 1” over right foot peg —-...

endless-sphere.com

.

You may have to buy both left & rite

 

[PaPaSteve]

Hydraulic leverage ratio's are based on piston sizes and how much volume of fluid is moved or absorbed by each piston.
Assuming the hand lever ratio is the same then, in your case a smaller diameter piston in the master will be required to accomplish the desired effect.
Measure the diameter of what you have and go smaller.

 

[mj2412]

Hello, sorry for the late reply. I bleed the system carefully. I'm not missing power. I can lockup the rear brake easily. I'm missing controllability. I worked with the brass bearing at the lever at the weekend and made bushing with excentric holes to adjust the lever a little bit. It got a little bit better. The next step is to measure the piston sizes.
Thanks for all your help.

 

[DingusMcGee]

mj2412,

No immediate need to worry about piston size until, if you find that with the current lever and master cylinder, you cannot lockup the rear wheel while rolling on pavement by pulling the lever somewhat hard. It sounds like your can lockup the rear wheel easily — even better.