I bought a Boom/Swift-E? 2000W Grom Clone for $20

nice score (understatement of the year)

Did maybe 1 hour of work to the bike, the handlebars were stripped flopping around loose while the stem was fully rusted tight shut so that took about 30 minutes to remove 4x rusted allens with a breaker bar PB blaster the heck out of it and then tighten it back up with some shims in place, bars are solid but still rusty ugly for now.

then I took off some plastics to find out what is underneath, and found out how to pop the seat latch and found the circuit breaker under it and tested it quickly

Took off the bottom huge battery box that housed the SLA's the previous owner cut the top mounting straps, I will probably weld it back together but I may not need to use it since I will be using a 20s li-ion pack likely

Got the controller wiring mess sort of figured out, removed the stupid charge port that was in the fake gas take compartment that the previous owner plugged in to 120v power with a CPU power supply cord...

Front brakes are bled, rear are going to need to be done they are spongy

I mounted the controller back to its original home, but then started tracking down the ignition circuit since the key switch wiring has been ripped out of the bike, still not sure what will happen when I plug it in

I was about to plug it into my 72v pack from my Denzel dirt bike until I saw a slight drip of water coming out of the phase wires of the controller!! I immediately took a step back. I will have to open the controller tomorrow and at the least dry it out before I plug it in and fry everything before it even moves for the first time

Also after doing google searches for replacement plastics for this bike, I think this may be a Swift-E brand DongFang 2000w STT-2000E and not Boom E-vader brand. You can tell because of the front plastics are way different...There does not seem to be too much info on this forum about these tiny bikes, but there is a 70 page post on another forum I looked thru related to the Boom bikes. The Swift-E bikes seem to be even more rare. One thing to note is that it has the orange handlebar switches so i'm thinking its a really early model 2015 or even earlier. Also almost every one you see on the internet has a larger black controller, this one looks like a standard aluminum housing controller likely 24fet

any comments or knowledge on the topic feel free to drop a line

So I tore open the controller today and I am glad I did. It was still full of water even though it is sealed up fairly well from the factory, the controller was hanging upside down while it sat for months in the rain causing water to leak down the phases into the aluminum housing

a few things I see right off the bat, this is only an 18fet not a 24fet...But it does have 100v caps, so if I wanted I could run it off 96v

after letting the controller dry out for a few minutes with a fan on it, I felt confident enough that I could plug it in without a magical smoke cloud coming from any major components

I tracked down the ignition circuit which was already ripped out of the key switch and needed to be spliced and got that out of the way

Magically the speedometer came to life and showed 76.5v and the kph reader is flickering saying the bike is moving 23 kph. I turn the throttle in anticipation only to find that nothing happens, I try the kill switch I try the 3-speed switch nothing works. Then I also noticed that none of the lights on the bike work (horn, headlight, directionals) So I will need to check to see if the DC converter is working next

So I got the motor spinning but I think there is either an issue with the Three speed switch or possibly a bad hall sensor or two...Will need to test further

So i ended up taking the battery off my Denzel 4spd dirt bike and throwing it on this bike just so i could get the bike out for a test ride, since the bike is missing some of the plastics and they are so rare to find, i decided to remove the gas tank storage box for now and put the battery above the top post of the frame in front of the seat. I will need to weld some mounts but for now it is bungie corded for testing. The bike is actually very zippy and quick off the line with the small diameter wheel hub but it is still slightly slower than my daughters 72v ebay dirt bike which makes sense since the wheel size is 17” and the voltage is the same

Decided since I am missing the majority of the plastics to this once OEM fine looking machine, that I should change how to battery mounts to the bike. And in the process neaten up the wiring loam quite a bit too! I sadly removed the gas tank glove box which I did actually really like, but the battery fit there pretty perfectly after welding some mounts for it to sit in. Still need to fix the kill switch and find out why the front directionals aren't working but most everything else is working fine now. Still need a kickstand spring too which is quite annoying TBH, they are $10.99 online but I refuse to spend any money on this build since it is a low cost fun project right now.

So I welded two mounts for the battery to snug fit into on top of the frame, and also drilled two small holes on the bottom side of the frame and bolted the controller the the underside of the frame tube with rubber washers for vibration, now time to start neatening the wiring up!

Finished the Razor scooter E300 build, only took me about a day to complete but I needed to order an old school brake cable online which took about a week to come in the mail. Now you can use the thing since without brakes it was pretty scary to stop with your feet!

I did video the build but have no time to edit footage right now, used 2x hover board 10s 4.4ah in parallel and a 36v 800w controller and motor, still need to weld back on the kickstand, since the new motor is so huge I had to remove it and also extend the brake mount too!

I guess I will start using this thread as the junk thread, or small projects that I find under $100 that do not merit a thread

So I got home from work the other day and I go to the back yard, peek inside my shed...And my $20 E grom has fallen over into my Denzel dirt bike and the foot peg of the Denzel bike caught the E grom and ripped the seat pulling a few staples out of it, and the battery of the E grom was fallen on its side... Mayhem! My Daughter had tried to get her bike out and knocked them over and they are too heavy for her to pick up after



So either way I have been doing lots of wiring neatening to this bike, trying to simplify it where I can and shorten it to look more streamline now that the bike is stripped and more bobber' esque now

I started with the phase wires and the battery wires, and immediately found a bunch of OEM scary connections...I am glad I fixed them, awful loose slices under heat shrink and bad frayed wires on the breaker



I also fixed the three speed switch on the bike which I actually like since 3rd gear is like a little turbo mode for long travel only. The dash says 68kph in 1st, 79kph in 2nd and 82kph in 3rd which is very close to 2nd but you can notice it.
The funny thing is 82kph calculates to like 53mph so I was out riding with my daughter A she was on the Voloci 48v and she was much faster than me at full throttle...So I got the GPS app out and tried to get a speed run on the $20 E grom...I gave it all she had and got the speedo to hit 83kph on a slight downhill...the GPS app says exactly 30 MPH! No matter what I did the bike would not get the GPS to even 31mph LOLOL the exaggerated speedo is hilarious since I can see all the Ebike noobs getting these bikes being like my bike does 60mph YO!

Still have lots to do, but I will keep picking away at it

skeetab5780 said:

...LOLOL the exaggerated speedo is hilarious since I can see all the Ebike noobs getting these bikes being like my bike does 60mph YO!

Click to expand...

Yes that is hilarious but that makes me curious-- does the speedo get its signal from the humbotor?
Many controllers/display allow setting the tire circumference or diameter.

Ok so I was given two new free bikes, but when I went to go pick them up I could not just take them for free so I made them take $100 just because...

The first bike is a piece of junk Chinese clone enduro called the Cool Sports, the funny thing is the Zongsheng enduro bike that I converted with the Denzel 4-Spd drive had the exact same motor and wiring harness and carb and throttle so it made fixing this bike super easy... It had no spark for over 10 years. I ripped off the broken directionals and front headlight since the key/ignition was missing and I had to hack the thing to get it running. Had to break the gas tank lock also. But long story short I tore out half of the wiring harness and tracked down the short at the CDI box. Cleaned the carb and gas tank and she fired right up! The front left fork seal is completely blown out leaking oil everywhere which is always fun

The other bike is worth alot more, it is a 1982 RM80D the first year they were ever water cooled, It is a rolling chasis with all the parts and motor in a box. I am not sure if it should be restored to its 2-stroke glory or if I should make a sweet little E-pit bike

So the guy was so jealous I got his China bike running in one day, He was over the house checking it out. So I started it up let him ride it and then I actually gave it back to him! He was so happy

Now I have more room to work on the real GEM the 1982 RM80D!

So here is the next free project junk scooter I will need to get running! Looks to be missing the front wheel and the battery tray cover

I already know before I even take it home, that my daughter will always want to ride this thing! So I will likely replace the motor and controller with something much more powerful!