Surron Light Bee Rear Moto Brake Install Guide
Tools Needed:
- Phillips head screwdriver
- 5mm Allen key
- 10mm wrench
- 12mm socket
- Torque wrench
- Blue Loctite
Read This Before Starting Your Install:
This guide walks you through installing a rear moto brake kit on a Surron Light Bee. The kit includes a dual caliper bracket, a 240mm rotor, and an Ultra Bee OEM rear brake assembly (master cylinder, brake line, and rear caliper) that ships pre-bled so you can skip the bleed if you're careful during install.
This is the handbrake portion of the build. If you're planning to run a foot brake too, that's a separate kit and a separate install. What you get out of this upgrade is real moto-style stopping power on the rear: a bigger rotor, a proper caliper, and a master cylinder with a lever up on the bar instead of the stock setup.
The job is doable at home with basic hand tools. You'll pull the battery and battery tray to route the new line, drop the fork stanchion slightly to free the brake line, swap the rear caliper bracket and rotor, and mount the new caliper on the dual bracket. The trickiest part is finessing the pre-bled line through the frame without pulling the master cylinder apart.
Budget time at the end for a proper bed-in procedure. New pads on a new rotor need it, and skipping it leads to squeal, glazing, and brake fade. Plan on an hour or two of slow, deliberate riding after the wrench work is done.
Install Steps:
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01
Remove the battery
Pull the battery out of the bike so you have room to work and can access the battery tray hardware.
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02
Remove the front plastic piece
There are two Phillips head bolts on the outside of the plastic piece. Take those out. Then move to the inside of the frame and remove two M5 bolts. The plastic piece comes free.
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03
Remove the battery tray hardware
On both sides of the bike, remove the matching bolts holding the battery tray. Then remove the two top controller bolts and the two Phillips head bolts on the bottom of the controller. Pull the battery tray out. This gives you the clearance you need to feed the stock caliper and the new master cylinder line through the frame.
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04
Remove the rear wheel and stock caliper bracket
Pull the rear wheel. Use a 5mm Allen key to remove the stock caliper bracket bolts and take the stock caliper bracket off.
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05
Feed the stock caliper out through the frame
With the battery tray out of the way, slide the stock caliper back through the frame so you can pull it out without cutting the brake line. This keeps the stock brake intact if you want to save it.
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06
Loosen the triple clamp and drop the stanchion
Loosen the top and bottom triple clamp bolts so you can slide the fork stanchion down just enough to clear the brake line from behind it. Pull the stock brake line free. Leave the stanchion loose for now. You'll use the same gap to feed the new line through in a minute.
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07
Remove the stock master cylinder from the bar
Unbolt the stock master cylinder from the handlebar. Remove the ignition cover (two bolts) and unplug the brake sensor so the stock assembly comes off completely.
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08
Remove the lever from the new master cylinder
To keep the Ultra Bee rear brake assembly pre-bled, pull the lever off instead of disconnecting the line. Use a 10mm wrench on the nut underneath and a 5mm Allen key on top. Take off the nut and washer, slide the bolt out, and the lever, plastic piece, and small internal piece all come off.
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09
Route the new master cylinder and line through the frame
Finagle the new master cylinder past the battery plate the same way you pulled the stock caliper out. Feed it up to the handlebar. Pull the fork stanchion down a bit more if needed and slide the new brake line behind the stanchion so it routes correctly.
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10
Mount the master cylinder on the bar
Bolt the master cylinder to the handlebar before you reinstall the lever. It makes lever reassembly much easier. Reinstall the lever assembly. If you leave the plastic piece off (personal preference), just snug the lever bolt until it's tight. Don't expect it to bottom out.
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11
Strip the stock Ultra Bee rear caliper bracket
Take the caliper off the stock Ultra Bee rear caliper bracket. If the little black spacer won't come out, crack the bleeder valve and it'll pop free, letting you slide the bracket off the caliper. Use a 12mm socket to remove the post off the bracket. Pull the small rubber piece and the metal pad spacer off as well. You'll move these parts to the new dual caliper bracket.
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12
Build up the dual caliper bracket
Put a little blue Loctite on the threads of the post you just removed and thread it into the matching hole on the dual caliper bracket. Use a wrench to tighten it. Slide the rubber piece back in and set the metal pad spacer in place.
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13
Swap the rear rotor
Take the old rotor off the wheel and install the new 240mm rotor. Torque the rotor bolts to 8 Nm. This is the one spec in this install where you want to use a torque wrench.
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14
Mount the new caliper on the dual bracket
Slide the new moto brake caliper onto the dual caliper bracket.
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15
Install the wheel with the caliper assembly
With the caliper mounted on the dual bracket, slide the whole bracket over the rotor on the wheel. Then slide the wheel and caliper bracket onto the swing arm together. Leave the chain draped over the top of the swing arm on the right side so you don't have to pop the master link. Slide the axle through.
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16
Reinstall the chain and finish the rear
Drop the chain back over the sprocket and spin it into place. The rear end of the moto brake install is done.
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17
Reassemble the bike
Work backward through the teardown. Retighten the triple clamp bolts, reinstall the battery tray, controller bolts, inner frame bolts, plastic piece, and battery. Make sure nothing got missed.
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18
Bed in the brakes
This is the most important step. New rotor and new pads need a proper bed-in or you'll get squeal, smooth spots, and brake fade. Ride at 10 mph, slow down to about 3 mph without locking up the rear, then cruise for 30 seconds to let the brakes cool. Repeat 10 to 15 times. Move up to 20 mph and repeat, then 30, then 40. Plan on one to two hours of this. Never make a full stop that locks the wheel during bed-in. The goal is to bring heat up slowly and let the pads find their contact pattern on the rotor.
Common Mistakes:
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Cutting the stock brake line instead of feeding the caliper through the frame.
Pull the battery tray first. That clearance lets you snake the stock caliper back through the frame intact, so you can save the stock brake as a spare.
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Disconnecting the new brake line and losing the pre-bled setup.
Remove the lever from the master cylinder instead. 10mm on the bottom nut, 5mm Allen up top. Route the whole assembly as one piece and reinstall the lever on the bar.
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Trying to pull the stock brake line without dropping the fork stanchion.
Loosen the top and bottom triple clamp bolts and slide the stanchion down enough to clear the line. Do the same thing in reverse when feeding the new line through.
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Skipping the bed-in or locking up the rear brake during it.
Ride at controlled speeds (10, 20, 30, 40 mph) and slow down without fully stopping. Let the brakes cool between each pass. Bring heat up gradually over one to two hours.
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Fighting the little black spacer on the stock Ultra Bee caliper bracket.
Crack the bleeder valve on the caliper. The spacer pops right out and the bracket slides off.
FAQs
Do I have to bleed the brakes after installing this kit?
No, if you're careful. The Ultra Bee OEM rear brake assembly ships pre-bled. To keep it that way, remove the lever from the master cylinder (10mm wrench on the bottom nut, 5mm Allen up top) instead of disconnecting the brake line. It's more disassembly, but you skip bleeding.
Why do I have to pull the battery and battery tray?
You need the clearance to feed the stock caliper out through the frame without cutting the line, and to route the new master cylinder and brake line up to the handlebar. There's no way to snake the lines through with the battery tray in place.
What's the torque spec for the rotor bolts?
8 Nm. If you're only going to use a torque wrench on one thing in this install, use it on the rotor bolts.
Do I need to keep the plastic piece on the brake lever?
Personal preference. In the video the installer leaves it off. If you leave it off, the lever bolt won't bottom out, so just snug it until it's tight. You can reinstall the plastic piece if you prefer the stock feel.
How long does the bed-in take?
Plan on one to two hours of deliberate, slow riding. Start at 10 mph and do 10 to 15 controlled slowdowns (not full stops), letting the brakes cool between each. Then step up to 20, 30, and 40 mph. Skipping this causes squeal, glazing, and fade.
Can I install the foot brake kit at the same time?
The foot brake kit is a separate install. This guide covers the handbrake (rear moto brake) install only.