KHB - Honda CR125

Show off your E-Scooter or Motorcycle creation here.
Post Reply
kreal   1 W

1 W
Posts: 60
Joined: Jan 18 2016 1:52pm

KHB - Honda CR125

Post by kreal » Jun 11 2021 2:07pm

Honda CR125 - 1989 Donor bike

$965
Screenshot 2021-06-12 at 01.53.54.png
Screenshot 2021-06-12 at 01.53.54.png (753.17 KiB) Viewed 484 times
$319
Motor: QS138 70H V3 at 72v
Screenshot 2021-06-12 at 01.56.32.png
Screenshot 2021-06-12 at 01.56.32.png (487.13 KiB) Viewed 484 times
$310 +-
Controller: VOTOL EM150-2SP
Screenshot 2021-06-12 at 01.58.47.png
Screenshot 2021-06-12 at 01.58.47.png (327.5 KiB) Viewed 484 times
$740
Battery: 72V 40AH 4000W(5A)
60A BMS, might need more, any suggestions on aliexpress ?
Screenshot 2021-06-12 at 02.11.44.png
Screenshot 2021-06-12 at 02.11.44.png (292.94 KiB) Viewed 477 times
Throttle handle: Normal gas throttle with cable to Potentiometer
Screenshot 2021-06-12 at 02.07.40.png
Screenshot 2021-06-12 at 02.07.40.png (313.99 KiB) Viewed 484 times
Last edited by kreal on Jun 12 2021 12:10am, edited 1 time in total.

EVOXY6768   10 mW

10 mW
Posts: 30
Joined: Jun 28 2020 9:31pm

Re: KHB - Honda CR125

Post by EVOXY6768 » Jun 11 2021 4:18pm

Will be following your build especially with you using the V3 motor with gear box :thumb:

kreal   1 W

1 W
Posts: 60
Joined: Jan 18 2016 1:52pm

Re: KHB - Honda CR125

Post by kreal » Jun 21 2021 9:16am

I made the 125cc motor work, and it purrs like a kitten now. Also restored it to almost original with colors etc.

Restore plastic to orginal color and state as best possible.
Fixed hole and cracks in plastic with superglue and baking soda, and putty.
Change handle bar to 30 inch ( better in jungle ) and added over bar for more stiffness.
Changed back tire to new.
Changed foot pegs to bigger.
Changed exhaust.
New seat cover, orginal color
New front brake lever.
Changed almost all nuts and bolts.
New gasoline hose and filter.
Washed air filter and dipped in new oil.
Cleaned engine, clutch and carb.

Still missing, gas tank.
Screenshot 2021-06-21 at 21.17.16.png
Screenshot 2021-06-21 at 21.17.16.png (2.83 MiB) Viewed 332 times
So I was thinking about maybe adding a hub motor to the back wheel, and making it a hybrid instead, carrying the battery in a backpack for example.

·Rated Power: 3000W (6000kW peak in few seconds)
·Rated Voltage: 72V
Screenshot 2021-06-21 at 21.15.23.png
Screenshot 2021-06-21 at 21.15.23.png (197.27 KiB) Viewed 333 times
That would allow me to sneak out to where I ride in the jungle, without my neighbour being pissed by the loud loud engine.

Also could place the hub motor in the front wheel and make it 4WD, could make for some interesting Enduro.

Any input ?
Last edited by kreal on Jun 22 2021 3:49am, edited 1 time in total.

j bjork   100 kW

100 kW
Posts: 1068
Joined: Aug 31 2018 3:01pm
Location: Linköping, Sweden

Re: KHB - Honda CR125

Post by j bjork » Jun 21 2021 12:02pm

I think the bike seems expensive for an old bike.
Cant you find a newer one with a blown engine or something for less money?

The battery pack, just no.
If it is built for 60A discharge a change of bms wont make it suitable for 200A.

Other than that I think your original plans were good.

I dont think a hub motor on a gas dirtbike is a good idea.
It will only get heavy and handle badly in the terrain.

Elektrosherpa   100 W

100 W
Posts: 127
Joined: Feb 07 2021 8:19am

Re: KHB - Honda CR125

Post by Elektrosherpa » Jun 21 2021 12:05pm

kreal wrote:
Jun 21 2021 9:16am
Also could place the hub motor in the front wheel and make it 4WD,
A "2WD".... for a "4WD" you had to add two more wheels :twisted:

hugok   10 mW

10 mW
Posts: 26
Joined: Mar 05 2021 5:40am

Re: KHB - Honda CR125

Post by hugok » Jun 21 2021 12:42pm

I would sell it and buy a newer bike without / with blown motor.

User avatar
stan.distortion   100 W

100 W
Posts: 262
Joined: Jun 12 2019 12:53pm

Re: KHB - Honda CR125

Post by stan.distortion » Jun 21 2021 3:59pm

hugok wrote:
Jun 21 2021 12:42pm
I would sell it and buy a newer bike without / with blown motor.
+1 to that, if it's running well then selling it on would be best imo. Older off road bikes are (a bit) collectable and that one looks quite clean. Also,if you're set on hub motors and want something off road, it would be a waste to do it with that bike imo, suspension travel is it's virtue and adding lots of unsprung mass will effect it badly. Something without much travel like a flat tracker or Baja sled might be fun and maybe could work very well 2wd but something more modern going cheap with a mid motor is be best for a quick a off roader.

Maybe check lipo packs, they can pack a serious punch of amps for a low cost but don't last long (a few hundred charges usually) and can burst into flames and burn your house down if you're not careful with them! Incredible power for hardly any weight but not great energy density, other chemistries are far better for that and far lower cost in the long run (especially if the damn things burn down the bloody shed! ;) ).
Projects indirectly sponsored by https://www.dash.org/

kreal   1 W

1 W
Posts: 60
Joined: Jan 18 2016 1:52pm

Re: KHB - Honda CR125

Post by kreal » Jun 22 2021 3:50am

Elektrosherpa wrote:
Jun 21 2021 12:05pm
kreal wrote:
Jun 21 2021 9:16am
Also could place the hub motor in the front wheel and make it 4WD,
A "2WD".... for a "4WD" you had to add two more wheels :twisted:
True :D

kreal   1 W

1 W
Posts: 60
Joined: Jan 18 2016 1:52pm

Re: KHB - Honda CR125

Post by kreal » Jun 22 2021 3:51am

kreal wrote:
Jun 22 2021 3:51am
stan.distortion wrote:
Jun 21 2021 3:59pm
hugok wrote:
Jun 21 2021 12:42pm
I would sell it and buy a newer bike without / with blown motor.
+1 to that, if it's running well then selling it on would be best imo. Older off road bikes are (a bit) collectable and that one looks quite clean. Also,if you're set on hub motors and want something off road, it would be a waste to do it with that bike imo, suspension travel is it's virtue and adding lots of unsprung mass will effect it badly. Something without much travel like a flat tracker or Baja sled might be fun and maybe could work very well 2wd but something more modern going cheap with a mid motor is be best for a quick a off roader.

Maybe check lipo packs, they can pack a serious punch of amps for a low cost but don't last long (a few hundred charges usually) and can burst into flames and burn your house down if you're not careful with them! Incredible power for hardly any weight but not great energy density, other chemistries are far better for that and far lower cost in the long run (especially if the damn things burn down the bloody shed! ;) ).
I cleaned it up good. No one cares about Older off road bikes "collectable" around here though. And it's impossible to find "broken" bikes around here as well. Trust me I've tried.

kreal   1 W

1 W
Posts: 60
Joined: Jan 18 2016 1:52pm

Re: KHB - Honda CR125

Post by kreal » Jun 22 2021 3:57am

But yeah, I will put this project on hold, as I didn't know I could fix the motor as good as it's running now.

Post Reply