BGX, My newest build

biknut

biknut

Well-Known Member
This is Bullwinkle, my new build. The donor bike for this project was a Bigniu BGX. It's one of the new generation high speed, low torque eBikes coming out in the last year or so. It wasn't too shabby in stock form, with a claimed 1500w motor, and 40 amp controller, which actually put out over 2000w. I probably could of lived with that but it had one major flaw. It's gear drive hub motor has too much noise coming from its metal gears.. Besides that, it's the best looking eBike I've owned. That makes it a prime candidate for upgrading. This is the most extensive build I've competed so far.
The first thing I did was rebuild the stock 48v battery, turning it into a 72v 20ah pack. I replaced the stock 40 amp controller with a Russian Thermo Nucular F24, adjustable up to 500 amps. I'm running 80 amp. The new motor is a no name ,but probably QS, direct drive 5000w hub motor. My goal was to keep the bike looking as stock, and turn it into a decent street bike capable of keeping up with traffic. I feel like I achieved my goal. Changing the settings is easy, but for now I'm running it at a modest 80 amp, 5000w good for about 50 mph.
Bullwinkle sighting at the bluffs..jpg
wiring side cover.jpg
It's alive 1 2 25.jpg
 
biknut said:
This is Bullwinkle, my new build. The donor bike for this project was a Bigniu BGX. It's one of the new generation high speed, low torque eBikes coming out in the last year or so. It wasn't too shabby in stock form, with a claimed 1500w motor, and 40 amp controller, which actually put out over 2000w. I probably could of lived with that but it had one major flaw. It's gear drive hub motor has too much noise coming from its metal gears.. Besides that, it's the best looking eBike I've owned. That makes it a prime candidate for upgrading. This is the most extensive build I've competed so far.
The first thing I did was rebuild the stock 48v battery, turning it into a 72v 20ah pack. I replaced the stock 40 amp controller with a Russian Thermo Nucular F24, adjustable up to 500 amps. I'm running 80 amp. The new motor is a no name ,but probably QS, direct drive 5000w hub motor. My goal was to keep the bike looking as stock, and turn it into a decent street bike capable of keeping up with traffic. I feel like I achieved my goal. Changing the settings is easy, but for now I'm running it at a modest 80 amp, 5000w good for about 50 mph.
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How much did that little baby cost you? It's got to be upwards of three grand.
 
I love the wide tires on it. You can't really do that with a gas motor because the tire rubs the chain unless you get this big ass adapter thing put on there and that's awkward as heck.

So, the battery is in the frame and the gas tank is actually storage or do they keep the battery in there? I think they would put it in the frame to help balance the bike instead of of high like that I dont know,
 
Would you be so kind as to post a couple pictures of the underside of your seat I want to put a bobber seat on my bike and I'm not quite sure how I can do that with no eat post cuz I don't want the post on there.
 
Wevil Kenevil said:
So, the battery is in the frame and the gas tank is actually storage or do they keep the battery in there? I think they would put it in the frame to help balance the bike instead of of high like that I dont know,
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What looks like a gas tank really is the battery. The only difference is originally it was 48v 50 amp. I rebuilt it to 72v 80 amp. It's a little top heavy, but it's not an issue when riding. Probably would be if it was more than 20 ah.
 
There's a flat 1/4" aluminum plate welded to the frame under the seat. The factory that built this bike did a good job on a lot of little things.
 

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Well that didn't take long. I blew up the nuc, and the motor. It sure was fun. On a positive note I got to experience what 14 hp feels like on a 100 lb bike. It was way too fast for my kind of 71 yr old street riding. I'm happy with 7 or 8 hp. My Stealth was only 6 hp back when I first bought it, and it did over 50 mph.

So not to fear, I already rebuilt the build, and It's even better now. The nuc wasn't really all that.

So I took it out last night and rode 35 miles through the city. Mostly side streets but some major traffic streets. My testing has shown that my battery is the weakest link. With that in mind I have the controller battery amp set to a modest 70 amp. Even at this low setting it's pretty fast. The BGX, which I renamed Bullwinkle, feels faster than the Stealth. Lsat night in traffic I got over 50 not trying .
Bullwinkle Best.jpg
 

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I graduated from that university a few years back so I'm good there. Hmmm well I wish you'd share what happened to help keep others from making the same mistake and blowing up their ride.

Are you going to get it fixed or.... Cuz I know a cripple, half blind and mostly deaf little old lady who needs a dependable ride to pick up orphans to take to church on Sunday ... in Cambodia... During monsoon season...and the winter solstice in the rainy season...

Ok ok I'm kidding... Im the little old lady, I ain't cripple deaf or blind and I'm not in Cambodia during monsoon season and there ain't no orphans... But the rest is true ...except the solstice rain thing...but I know an orphan who had a ear infection once if that counts!!!

But seriously, how badly could it be damaged?

Burned up the brain box? Fried the battery/ motor? Left it on the train tracks and a train hit it? Are you going to fix it or sell it...?
 
Wevil Kenevil said:
I graduated from that university a few years back so I'm good there. Hmmm well I wish you'd share what happened to help keep others from making the same mistake and blowing up their ride.

Are you going to get it fixed or.... Cuz I know a cripple, half blind and mostly deaf little old lady who needs a dependable ride to pick up orphans to take to church on Sunday ... in Cambodia... During monsoon season...and the winter solstice in the rainy season...

Ok ok I'm kidding... Im the little old lady, I ain't cripple deaf or blind and I'm not in Cambodia during monsoon season and there ain't no orphans... But the rest is true ...except the solstice rain thing...but I know an orphan who had a ear infection once if that counts!!!

But seriously, how badly could it be damaged?

Burned up the brain box? Fried the battery/ motor? Left it on the train tracks and a train hit it? Are you going to fix it or sell it...?
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It wasn't too spectacular. One of the bolts on the rear rotor came loose, and ate through the motor cable. It's kind of a common failure. It caused one of the phase wires to short to a hall wire, which blew the hall circuit in both the motor, and the controller.

Not to worry, I already replaced both parts, and it's running better than ever again, but this time I used a torque wrench on the bolts. Probably never be able to get them loose again lol.
 
Good to know!

When I messed with electric I made my front supports for holding the wheel still, I used leaf spring and it held rather nicely. Yeah unfortunately they don't use the best quality metal when building those things but you know you can't expect them to last forever!

Good to know it's all good.
 
biknut said:
It got up to 54

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Without a helmet? Bro... No. You have to at least set a good example for the young people, you might not feel it so much because you're running an electric but because we run gas we are under extra scrutiny and no matter if it's electric or gas they hold it against us the gas riders. man wear your safety gear PLEASE!?! At least spare your wife from having to take care of a vegetable for the rest of her life.
 
Hey Rocky watch me pulla rabbit out of my hat!

Not again!

Nothing up my sleeve!
RIPPPP...
Presto!
Grrrr...
Oops I must have grabbed the wrong hat.

Now here's something we hope you really like!

I always liked Simon bar sinister....

Don't be a victim of Simon bar sinister.
 

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