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Transforming my dad's scrapped RX 100 into a custom electric motorcycle

I've used parts from different bikes. The front disc is of a Bajaj Pulsar 220 & the rear rotor is of a Royal Enfield Classic 350.

BHPian TechSavvy recently shared this with other enthusiasts.

Presenting EDROIT, a one of its kind custom Electric Bike

Prologue

I’ve had the mind to create my own Electric bike for my dad for the longest time, been about 3 years now. Initially, the concern to source a good quality battery stopped me from taking the plunge, later was the cost. But this summer, back from college, I didn’t think twice and dipped straight in and gave myself two weeks and ordered the main components - the battery and hub motor.

After the arrival of the parts, I was damn excited and wanted to just begin the build but I was faced with many complications - one also being my summer class which ended a month after I got the parts.

I’ve built the bike on the RX100 chassis at least as much of what was left of it in the final version. This scrap condition bike was of my dad lying around in storage for 20 years and to take that out itself took a long time. If someone was to ask me how much time did this build take I would say maybe lots not because building the bike itself took time, procuring parts, doing the custom fitting on the frame, welding, cutting then changing components which didn’t fit itself maybe took 1 month.

Diving into the spec sheet

This bike runs on a 3000-watt hub motor, used it for its “easier” installation and because this hub motor was of better quality than the standard belt-driven BLDC motor I was finding. Although I wanted to initially put a belt-driven system so I could mess with the gearing ratio and do wheelies, a higher quality component hub motor outweighed that requirement.

In the battery department, it runs on a 72V lithium phosphate battery with 42aH capacity. I chose phosphate over lithium-ion because of its charge cycle life which is almost double that of lithium-ion. This battery is definitely a lot chunkier and heavier (approx. 5kgs heavier) than the same lithium-ion counterpart would’ve been but the main advantage of it is that it's way more abuse friendly because all I care about is giving it full throttle all the time and that would’ve messed up the lithium-ion battery way, way faster.

The bike has a load-carrying capacity of 300kgs. Tops out at 80kmph(tested) and has a range of 70kms, the range has yet to be tested but with even just pulling all the time it is still giving me 40kms and has still some voltage left. Although, I’m not really happy with my battery selection because the aftersales support from the company is horrible. A 72V battery charges upto 82V but my charger stops it at 80.5V and I only ride it till 73V although it can be discharged more for some range which I’ve actually experienced and it once dropped down to 64V where the max current was very low so there was basically no pull in the motor.

What's custom on this

Basically everything. Let’s go one by one. Swingarm, yes it’s a local RX100 swingarm but it's cut and extended because I’ve put a wide 120/80 R17 Apollo radial tyre in the rear (my bike looks sexy only cause of this meaty tire) so accommodating that was a challenge.

Frame. Yes. The battery would not fit in. Basically, a dozen frames I tried so I went with the RX100 frame, cut that cause essentially it would keep the kerb weight light. Look at the pictures and try understanding the difference yourself cause there’s a lot which went wrong behind the scenes which I can’t type cause I don’t want to type and make this blog long but also I don’t want to demotivate anyone if they are trying to build something like this.

Lighting department? Yes. Put two fog lights in front, looks gorgeous, basic KTM indicators and a slick tail-light. Pretty simple but more than gets the job done. I actually find it classy, don’t know about you.

Rear suspension? Yes. Got dual gas shocks from the Pulsar 220. Front fork? Yes. From Pulsar 150.

Tyres? Like I mentioned, the rear tyre is Apollo aplha s1 radials 120/80 and the front is nylon 100/80, both R17, great tyres and wider than recommended.

Brakes? The trouble I had to go through to make this bike, haha. Essentially the brakes operate like that in a scooter or any other electric bike, both with the use of levers in hand. Since I’ve disc both in front and rear, this was a challenge. I had to source a left hand master cylinder and brake pipe which was long enough to run from the front handlebar to the rear brake calliper. Braking performance is solid cause I’m running Pulsar 220 front disc and Classic 350 rear disc so these brakes were designed to stop bikes of more than 150kgs from speeds higher than 100kmph but since this bike tops out at 80kmph and doesn’t even weigh 100kgs (that’s what I reckon from my quick math), you get the point…

Talking about the riding feel

I’ve personally ridden the Ather 450x in Delhi and that scooter could be faster accelerating but is in no way close to the comfort and rawness that this bike give. Same said for Revolt RV400, a week after riding this bike everywhere I took my dad to test ride that bike to compare it with my bike and EDROIT is faster to 60 and the riding posture is so much more comfortable and practical.

This bike handles like a dream, no complaints there. It has amazing torque, not enough to lift the front wheel off but is a master in closing bumper-to-bumper gaps. Essentially it is as fast as my Burgman 125 but the way in complete silence it delivers that power and when you let off the throttle it feels like you’re gliding in the air.

Let me elaborate and try to paint the picture as much as possible. You let off the throttle, you’re at 60, there’s no traffic in front and it’s a pleasant cloudy day. The tire noise doesn’t bother you, there’s no vibration on the bike so you feel disconnected from the traffic, so the honking doesn’t bother you, and you don’t feel the rush and hastiness of work on your mind. The wide tires grip so well that the bike feels weightless. You have a wide handlebar upright seating posture, don’t have the hassle of shifting gears or using the clutch everything comes easy, everything is supple and then add the cherry on top the novelty factor which never dies cause everyone and I mean everyone is looking at you.

Try to put yourself in these beautiful shoes and maybe you’ll understand what this bike is all about.

Even when you want to talk about pulling, you don’t mind going full throttle on this bike all the time like you would mind going in an ICE propulsion bike cause this one is vibration free and the annoying honing of some bikes at low revs in traffic is not there and hard acceleration and hard braking in city traffic is tiring in normal scooters and bikes and might be annoying too but that’s definitely not the case in this EDROIT.

I want to keep this post short, if I have missed on some details please feel free to ask me cause answering questions would be more comprehensive than maybe putting it all in one big read.

Afternote

There are two reasons I made this bike, I’ve got a lot of hate while making this bike from local vendors whom I was purchasing the parts from, people who saw me making the bike, RX100 die-hard fans, etc. First, I make a big quirky electrical project almost every year and this time I wanted to mess around with electric propulsion. Secondly, my dad is a big die-hard fan of bikes. He’s owned this RX100, an RD350 and would’ve went on to own more modern bikes but he got an injury 20 years ago which prevents him to understand the sensitivity of the rear brake on bikes which is mounted on the right side. This solution kind of takes care of that problem. He’s been riding scooters for the last 20 years and loves his Burgman more than my Elantra. I find that kind of crazy to believe, although Burgman is a great scooter I can’t believe how well it handles. Anyhow, I’m happy to report I’ve done a good job in upgrading his ride.

Disclaimer

Mechanicals of this bike are sorted but beautification and some wiring are left which would be done later cause I had to leave for uni and funnily enough I worked till the last day but still a whole summer wasn’t enough to complete-complete this bike. What's next is to obviously get this painted, think about the fuel tank and put a better smaller seat cause this original RX100 seat is kind of chunky and is eating up the bike.

Bunch of video links

  • Link 1
  • Link 2 - In this video, the battery cage was not welded in so there were a lot of rattles so I couldn't cruise at high speed. Also I was only riding with the front brake so kind of a boring ride but still you can assess the ride quality.
  • Link 3
  • Link 4 - A small clip of me trying to learn spray painting the bike to save painting costs for the frame but also cause I didn't have the time to get it professionally done.
  • Link 5
  • Link 6
  • Link 7

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