Edit: Kit now available here, details on page 2 of this thread: https://electroandcompany.com/products/yz-emx-kit
After months of hard work, the YZ-EMX conversion project is finally completed! What started as a brand new 2021 YZ-250F rolling chassis is now a fully converted E-bike that is 100% moto ready. But the best part is we will be offering the full kit that includes everything needed to convert the previous generation YZ-F chassis to an electric race weapon through Electro&Co! The kit will include a custom battery, controller, wiring harness, and all of the necessary brackets to make this a fully bolt on kit with no frame modifications required. For anyone with a blown up four stroke out there it is a very cost effective way to give your bike a new life, and the entire project can be completed in just one day. Here are a few details about the kit, which will be available by early next year:
- Price range will be $5-7k depending on options chosen. We will offer a base model (shown here), as well as an upgraded version with a higher capacity battery (5.5+ kWh vs 4.7 shown here) and TruMoto controller with integrated phone app for full adjustability of power, acceleration, regen braking, and top speed.
- Fits 2018-2022 YZ450F and 2019-2023 YZ250F
- Total weight of the bike is only 242 lbs (over 20lbs lighter than a Stark)! Plus, without the rotating inertia of the ICE crank this bike feels like an incredibly fast 125 out on the track that can be thrown around with ease
- Power is roughly equivalent to a fast 250F. It's always hard to compare power output from electric to gas, but the bike will pull 450s right out of corners then taper off to 250-like power up near the top of the RPM range
- No frame modifications necessary, aside from removing two small tabs that hold part of the old airbox on (to make room for the battery). This bike could easily be converted right back to a ICE bike if desired.
- QS138 internal gear reduced motor (pretty standard for conversion these days)
-Swappable battery packs! The battery pack can be pulled directly out from the top of the bike, allowing for quick swaps at the track. This allows the overall bike to be significantly lighter than a Stark or Alta
- Notice how all of the engine mounting points on the frame are joined similarly to how it would be with the ICE installed. This is an important factor for handing often overlooked on conversions like this.
Here is a quick video that the owner of Electro & Co did on our first test day with the bike for more information. There is GoPro footage of me riding the bike for the first time, as well as some initial thoughts shared at the end. I'm super excited to get this kit released, to me the bike is absolutely a viable option for most riders and provides a lot of value for the cost. Even on a higher speed track like this lap times were competitive with my Stark Varg, and considering building this bike would cost only about 1/2 as much as a Varg I think it's a great option. There are still small refinements to be made before we release the kit, but I figured this would give people time to adjust their holiday spending plans.
If you have any questions feel free to reply here, or send me a direct message.



let me know when it's as fast as a 450... seriously who wants a 250 type elec power..?
I'm sure you need all the power of a 450.....
Dig it. Really wish someone would consider a conversion kit for pitbikes. The crf125 frame with an electric motor would be so much fun.
My absolute nightmare.
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What’s the release date on the kit?
How much are replacement (additional) batteries? Do you garuntee that the batteries will be more or less future proofed, meaning there won't be a new battery form with future updates?
Continued availability of affordable replacement batteries are crucial imo.
This is very cool! Good job all around.
Above jm485 says early next year.
That looks good, much better than I was expecting. What is the run time?
Thanks I missed it the first time I read it haha.
When you say new battery form, are you referring to the shape? If so that will not change, this isn't a generic off the shelf battery, it is made to our specs and we're using every available millimeter to pack as much battery as we can into this frame. The battery pack isn't a wear item that needs to be replaced, with the current cells most riders can expect a couple hundred hours of riding without having to actually replace the battery.
I can get 20min or so at 250B class speed, so it will last long enough to finish most amateur length motos easily. This isn't going to go 30 +2 at the pro level, but that's not really the target audience for this kit and that's the reason why our bike is 20+ lbs lighter than a Stark.
I don't know, maybe all of the people who currently ride a 250F and don't need 60+ hp?
I would recommend reviewing bullet point 3, specifically where it says that the bike will pull a 450 right out of corners. . .
God! What kind of soy latte drinking wussy would convert a bad ass petrol burning motorcycle into an electric bike, might as well castrate yourself at the same time and identify as a female.
That's great work and a great possibility to convert a broken bike. Above all it looks super fun to ride.
Some like it and some don't, that's life.
Please add some warning to your post for the sake of readers whose manliness is so delicate and fragile that they need a combustion engine to feel like a man. They may feel threatened by the mere thought of riding an electric bike and be all weird about it, be nice and spare them this torment.
I saw someone using an electric edge trimmer once and now I’m gay
So you are not offering to sell replacement batteries so individuals could potentially have two or three batteries charged and ready to ride, since only one battery's enough. If I understood that correctly, or if replacement batteries are going to cost almost as much of the as the kit itself,, I would personally think long and hard before buying this.
Also is there any kind of BMS with this setup, or is the battery management simply you're on your own?
Pit Row
Electro & Co. sell many different batteries, so yes, as I understand it you will be able to purchase an additional battery with it. Yes, they're expensive. I'm going to guess in the $2000-$3000 range, especially for a higher AH battery. I believe the bigger one they are developing is 75ah which is huge.
I more or less have the same setup as this new kit on my own YZ conversion, but with a 51ah battery and I get roughly 20-25min of MX time out of it. And when I can ride from my house, I don't find the need to ride all day. A couple of motos and I'm good.
Can you race these bikes? Yes, without a doubt and I would like to race mine when the season starts back up next year in the Northeast. But the real advantage is in their silence, performance, and significantly decreased maintenance requirements. If you have any land near you to ride on, eMotos are a game changer. Mine certainly has been.
Very few people are going to trash a perfectly good ICE engine, and neither would I, nor did I for my conversion. The idea is to revive a bike with a blown motor and turn it into something new and ultimately far more convenient.
And as much as I love my conversion and am proud of what I accomplished, I would've gone with Electro and Josh's kit in heartbeat if the option had existed at the time. It is by far the most affordable conversion kit on the market away from building your own from scratch.
We will absolutely offer additional batteries, that’s the beauty of the swappable pack system! Additional batteries will likely be in the $2-3k range depending on chosen option. The battery packs also have a BMS already mounted within the metal case so it is truly plug and play, you will not need to buy anything in addition to the kit unless you want an additional battery pack.
I have built 2 of these with motor kits from Electro. Electro makes it a plug and ride scenario. I have done Hondas and the bikes are so fun to ride. I take mine to the track and have a track in my neighborhood I can ride after work. My ICE bike is well setup and I am able to ride both but not at my neighbor's track.
What kind of inverters are you running? Can it charge so you have enginebrake, or is it only positive drive? If regen, can you tune it?
No engine or battery cooling from what I can see?
Got passed by this bike at Argyll the other day. Took me a minute to figure out why the bike was so quiet. No clue it was an electric bike at first. Was very impressed by how great it looks in person as well.
Does the YZ-EMX handle similar to a Stark Varg? All the reviews I watch is how great the handling is and you can put the bike anywhere you want. Take lines you never could before.
This dude secretly watches gay porn!
on the bike: cool setup, I can confirm that it’s quite different (positive) to ride a bike this weight but without the inertia of a 450 crank internally.
There are so many parameters you can adjust to your personal liking. I have my modes set up so a true beginner can take it for a ride on mode 1 and full power in 3. Regen can be set to mimic 4 stroke all the way to 2 stroke roll. I am old and have no electronic skills but the program is very user friendly.
Very cool project!! It would be great to see a comparison with the Stark especially what HP on Stark the YZ-EMX matches. Most people can only run 40-50 HP on Stark, so it may have plenty of power. I think the 20-25 minute range with swappable battery will be a very compelling offering to amateur moto/practice day guys (me). Will you be offering a left hand rear brake? I have one on the Stark and it's a game changer for me.
Any idea what a rolling chassic can be purchased for to give me an idea of total cost?
The lower tier controller can be tuned to your liking with multiple pre-set maps actuated through a map switch on the bars. With the upgraded TruMoto controller, all of the parameters you mentioned are fully adjustable via our phone app with an intuitive slide bar system (similar to what Stark uses, but we offer more adjustability). The TruMoto controller also has an incredibly smooth and linear feel compared to other controllers on the market, and I would highly recommend going with that option.
As far as cooling is concerned, the first component that would be effected by heat would be the controller rather than the motor or battery. We'll be including a large heat sink to mount the controller to that will help draw heat away, and with our testing so far we have not run into any overheating issues.
Could this finally be the YZ350 I've been waiting for LOL. Nice work gents - enjoy. I can see many guys with blown up 4T's buying this kit
The YZ-EMX handles better than the Varg in my opinion, especially in tighter corners. You really don't feel the weight of the Varg on the track aside from those tight corners where speeds are low, and that is where the lower weight of the YZ-EMX really stands out. We were also able to get the weight very centralized (notice the battery goes into the tank and under the seat), so it has a great weight balance and feels even lighter than the Varg in the air as well. I think on tighter tracks this bike could be competitive with the Varg, but on more wide open tracks like Argyll the power deficit is hard to overcome even if handling is superior.
I'm not sure if we'll offer a rear hand brake, but any of the setups available should work just fine on this bike. It's essentially just a YZ-F as far as the chassis is concerned so any accessories that fit those bikes will fit this as well.
Cost for the rolling chassis will obviously vary with condition, but we got this brand new one for just under $4k. Starting with a brand new bike is definitely not a requirement and isn't going to be cost effective for most consumers, but since this was going to be the bike we would debut the kit on we wanted to start fresh. I would bet you can find a bike with a solid chassis that needs significant motor work for $2-3k.
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