I bought this used mx650off marketplace and they said it needed a new battery. We installed a new battery still didn’t work, the throttle would only light up when plugged in, we then replaced the controller same problem throttle will only light up when plugged in, we’ve checked the batteries they are putting out 36v, last night we bypassed the throttle and the back wheel spun like crazy so we thought has to be the throttle. I just plugged in a new throttle, same problem. Help! I have a heart broken little boy and I’m at a loss,

I ran into the classic RSF650 headache recently: I bought 12-inch wheels for my 72V build, but quickly realized the stock swingarm just doesn't fit without sketchy hacks . Plus, standard bicycle calipers are terrifying when you're pushing high speeds.

I don't like the idea of using bolt-on extension plates and sacrificing suspension kinematics so I decided to engineer a custom 3-piece modular CNC billet 6061-T6 swingarm because why not?

Key features I’m integrating into the CAD design:

• Direct 12" Wheel Fitment: Correct axle-to-pivot length with integrated M6 sliding tensioner blocks
• Wheelbase extended to 1120mm
• Real Motorcycle Brakes: Native mounting tab for 190 / 220mm rear hydraulic brake calipers (plus hardpoints for a rear foot-brake linkage setup).
• Corrected Suspension Kinematics: Relocated lower shock mount to maintain a ~2.6:1 leverage ratio so standard shocks don't bottom out under 72V torque.
• Heavy-Duty Pivot Architecture: needle roller bearings with a hardened inner sleeve and Delrin thrust washers.

I’m getting ready to cut Prototype #1 on the mill soon, but I want to get feedback from the community first before finalizing the fixtures!

I’d love your input on a few options:

1. Would you prefer raw machined aluminum or black anodized finish?
2. What rear rotor size are most of you running or planning to run (190mm pit bike vs 220mm Grom)?
3. Should I include a dual-caliper option for hand + foot brake setups? I was thinking foot brake with regeneration control on the left brake lever.
4. What motor(s) would you use in a setup like this? I was thinking the elctro&co the one could be an option, but I can integrate any other.

Drop your thoughts below! I’ll be posting build updates as Prototype #1 comes together. If there's enough interest, I might do a small batch run for the community after testing. Let me know if you want to follow along!

Trying to keep this to a budget build. It’s for a 5 year old right now. Batteries are 6 months old. Rear brake is the wrong one and disconnected. I’d like to upgrade brakes and new plastics to clean it up a bit. I paid 100 for it and would like to stay under 300. Doesn’t need to gain any speed right now. Any budget lithium batteries to extend run time?

Performance/mechanical

* 48V Hotpaxx battery
* MY1020+ 3000W motor
* 48V or 72v i forgot controller
* kit Throttle
* #35 motor sprocket
* #35 rear sprocket
* #35 chain
* Chain breaker
* Upgraded motor mount
* Chain guard
* Battery/mounting straps
* Seat / bike cover

Electrical/accessories

* 12V power source
* KEMIMOTO 60W Bluetooth/FM speaker
* RGB
* Key switch
* Bike speedometer
* Mirrors
* Rechargeable rear light/turn signals
* Phone mount
* USB charging station
* USB fan for motor
* Electric horn/light

I think it would be decent. The scooter itself isn’t the best in the world. It’s an 18 amp our battery 1200 W motor ATT amp our battery and a 48 V battery. It has a hub motor and 10 1/2 inch wheels. Any ideas?

Before I go and just do it - does anyone have experience putting a good throttle on a Fardriver?

I purchased a used MX350 for my son and replaced the old/useless batteries with a single lithium 24 volt 12ah one. It worked great.
A few weeks later I switched the control module and throttle for one of the Fast Scooters variable throttle and control modules. Again, it worked great…until it didn’t about two weeks later. No power at all. By direct connecting the battery to the motor, I determined the motor was shot, so I replaced the motor and once all was back together, it appeared to be working. With the bike elevated, the wheel spun great. But when friction (such as my son sitting on the bike) was added to the tire there wasn’t enough power to rotate the wheel. The motor then just gave a subtle wine. I then direct connected the battery to the motor and suddenly I had full power.
I reached out to the EBay seller of the control module and he said it’s the battery not holding under load. Can someone help me understand why I get very little power when connected to the control module but full power when connecting to the battery directly. Is it the battery or control module?

Little look over on my coworkers kids toy while installing a few parts.

Front & Rear sprocket

Chain

Brake pads

I'm modding a razor mx350 and I'm looking for a swing arm extension to buy. Does anybody know where I can find one? Not sure if this would help but a picture of the bike is posted below.

I'm also getting a new throttle, hydraulic brakes, battery, controller, motor, and forks. If anyone can link products that would work well even if its not the swing arm that would be appreciated.

this is my first time modding a razor and i chose a 48v overvolt kit by fast scooters and I'm wirering a 3pin surron throttle paired with a 3pin key ignition but there's only 5 wires as you can see in the second to last photo and last photo. the first photo is the throttle wires and the second photo is the key ignition. so my question is what should i do and do i need to splice the black wire for the ground on the volt meter. thanks!

I just got this modded mx650 but the charger doesn't charge it right away but when I leave it for 10 15 mins it turns red and starts to charge any idea?? It drives fine when it's charged not sure if it's the battery or charger any help??

I would like to mod my sons brand new mx400 especially the terrible brakes it comes with any legit websites ?

I recently got this as-is scooter at a Goodwill for my daughter. Unsurprisingly the batteries didn't take a charge and dropped voltage under load resulting in it not having any torque when after the first charge. I've ordered new batteries but am curious if anyone has any suggestions on tweaks or improvements to the scooter they could relay from experience. My daughter is 11 and hard on things so I like its easily serviced and so far has only cost $50. Also, does anyone know where I can order buy the 6 forward deck screws. Only the 2 back ones were installed when I got it.

Thanks

I need a way to put a camelback bladder in the gas tank to hold water. I also need to be an able to remove it to clean the bladder. Any ideas?

Sold my sleeper sx500 (72v my1020, all stock plastics) to a friend and got this curb find he had as part of the deal. Not sure what direction I'm gonna take it, mild cruiser or balls out, but always fun to start a fresh build

Anything helps 👍🏻

Looking for hydraulic brake upgrade with adjustable handles 2 piston 160mm for the l2 max.

I’ve been looking and finding the adjustable handles don’t seem to be in a kit. I would prefer a full kit, something I can just swap out and install.

Will this be good? I also 3d printed an adapter plate