Joe's E-bike build

I got the disc brake on the front Sunday. I test rode it again and it's pretty fast. It's quieter than I expected with the 530 chain. Not loud at all. Got the belt aligned properly. I had an issue with the rear sprocket. I think I forgot to torque down all the bolts because it developed a wobble and the adapter plate bent. This ultimately led to two of the little m6 bolts pulling the threads out of the hub. So I have to solve that problem next weekend. On one of my runs I used a speedo app on my phone. 42 was as fast as I felt comfortable with although its still pulling hard at that point. The tire rubs the battery under hard braking so when I tear it down for paint I'll have to extend the frame out an inch or two to prevent that. I was worried that might happen which is why I made that corner of the battery box round. The cheap fork performs well, even with so much weight on it. Plenty of damping and with the rebound adjustment set, the front end stays squatted down long enough to maintain traction on the front tire. All in all it's a blast to ride and once I get all the kinks worked out i think it will be reliable. I took a few more pics of the bike out in the daylight.
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The rear sags quite a bit when you sit on it. The chain looks super loose in the pic because of the angle of the swingarm when the bike is unweighted. The position of the front sprocket causes the swingarm to push downward when torque is applied. I tried doing a little burnout standing on my feet but the swingarm just pulls down and the seat rises. It won't break traction easily.
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Magura MT5 estop
The front brake was a whole ordeal. I ordered a whole assortment of different lines and fittings to get this working. Much of them were not needed in the end but I just wasn't sure how I would connect the mountain bike caliper to the motorcycle brake levers I have on it. I failed to realize that the caliper doesn't come with the M5 banjo bolt needed to attach the fitting. I had these M6 banjo bolts that came with some of the other fittings I ordered to experiment with and I just drilled and tapped the caliper for M6 threads. The gold banjo fitting is a Jagwire quick fit banjo. I drilled that out as well. I used the Jagwire hose which is very nice by the way. I recommend it. It's much more flexible and pliable than the other cheaper hoses I also purchased from Amazon. I did buy the actual Magura banjo fitting too, which fits an M6 bolt however the Jagwire stuff is nicer/more convenient so I opted to drill their fitting for the M6 bolt.
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This is the lever end/master cylinder end. The master cylinder uses an M10x1.25 banjo bolt. I got a banjo bolt with a bleeder screw for the rear brake and the bleeder turned out to be M6x1.0 thread so I was able to screw in the small MTB brake line fitting where the bleeder is supposed to go. Basically using the M10 banjo bolt as a thread reducer. This particular MTB fitting was sold described as "for Formula" I'm not too savvy about MTB brakes but I think formula is either a brand or model of bike brake. The fitting just had a straight M6x1.0 threaded end with the correct barb/olive for the Jagwire line(5mm OD). I trimmed the M10 banjo bolt down so that I could thread it into the master further without it interfering with the spring and piston inside. This allowed it to go in past it's banjo hole and seal with the sealing washers. I also faced the head of the M10 bolt with the grinder so that it's flat and provides a good sealing surface for the M6 sealing washer. I trimmed the M6 thread down on the MTB fitting too because it was too long to fit inside the M10 bolt. In the end it all worked out and I'm happy with it. I put DOT 5 brake fluid into the system. This is the silicone based kind. It should be compatible with both the Nitrile/buna n seals in the caliper and the EPDM seals in the master cylinder but we'll see. That's the main obstacle I was facing with this setup. Magura brakes are designed for mineral oil based fluids and the motorcycle stuff is for DOT 3/4/5.1 glycol based fluids. The silicone based fluid should work with both seal types from what I've seen on various chemical supplier and seal manufacturer websites. There is conflicting information about this however. So time will tell. If all else fails I will replace the seals in the caliper with EPDM rubber. I'm running a 2mm thick 203mm diameter rotor which, seems to perform satisfactorily despite the weight. I was easy on it but it did stop me from 40+mph without fade. I'll admit that it seems too small for the bike just looking at it. If I end up overheating this brake frequently I'll probably change the whole fork setup over to motorcycle stuff and take the weight penalty. 230mm rotors are available too so that's another option.

Still wiring to do and I need to make fairings/covers for the controller and set up the cooling system. More updates next weekend.

I want to thank all who have posted here, especially amberwolf for your input about the wheels and forks early on in the build. That really led me in the right direction. I've also been having a great time tinkering with the Lebowski stuff so thank you for turning me on to that. The stuff about crimps was enlightening too and I bought my very first set of crimpers. Very similar to the ones you showed me in your post. I don't know how I lived so long without them honestly. Ive been using them on all the pins and such for the bike. I still solder the crimps afterward but thats just me being paranoid, the crimpers work great! At some point I'd really like to invest in a high quality hydraulic crimper for the larger gauge wires.
 
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I started making a cover for the controller.1000005446.jpg
It's made from the drivers side front fender of an 03' LeSabre. Still haven't painted the bike yet. I put a DNM rear shock on it because the other ones were just too soft. The old ones had 250# springs and the new single shock has a 1000# spring. It's stiff but I'll be using this for groceries etc... so the extra weight capacity will be needed. I'm planning on putting bags on the sides of the seat.
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I put a big spring inside the fork to stiffen it up. I got the spring from work. It goes into a folding cafeteria table to assist the user in folding it up. It was about 3ft long but I cut it to the right size and it ended up working out. The tire doesn't rub the battery anymore but I'm still going to stretch the frame out about 2" when it comes apart for paint. I need room for a fender and I'd just feel better knowing the tire has plenty of clearance.
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I've been riding it on the weekends when I go to the garage to work on it. I ran the battery low one day and pedaled it without the motor about a mile. Even with the gigantic front sprocket the ratio to the wheel is pretty short. I can only go about 10mph with the pedals. It would be better if I had a way to disengage the motor. However, they are usable and its actually quite comfortable to pedal with the pedals being out in front of the rider.
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This is a screenshot from the top speed run I did. I only held this speed for a short time. I don't think it's smart to go this fast on the BMX front tire. The sidewall is too soft. The bike was actually very stable at that speed but I'm sketched out by the tire. Had to test it out though now that I'm more confident on it. Overall, it rides pretty good. I sit upright and it's comfortable. The turning radius is wide with so much rake. It has tons of torque even with the small controller. It's a far driver nd72360. 180 line amps and 360 phase amps. I think that's more of a peak rating honestly. It won't wheelie but from about 20mph on up it takes off like a bat out of hell if you give it full throttle. When I chose the pulleys and sprockets I sized them for the peak torque to be in that range. Video coming soon.
 
No video yet. Planning on ordering a GoPro this week. I have the cooling system set up now.1000005524.jpg
The water pump is 12v and runs off a buck converter along with the lights. There's no reservoir although I may end up adding one in the future. It seems to work well this way. The square thing with the acrylic sides is a flow meter for PC water cooling. The fitting on the top is a barb with a rubber cap on it. That's where I fill the system. The air bubbles settle in the flow meter and I have enough hose there to move it around and get the bubbles up to that top fitting. It took a couple days before they all worked their way up there.
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That's the radiator there on the side below the seat. The pump pulls coolant from the bottom of the radiator pushes it through the flow meter and then through the motor and back to the radiator. I'm planning on making another sheet metal panel with louvers to cover the radiator and help direct air through it. I just have a button to turn the pump on and off. The plan is to add some kind of thermostat to the circuit so that the pump only runs when it's needed but I haven't been able to significantly heat the motor no matter what I do. I don't think the controller is powerful enough to get it to that point. The motor gets warm to the touch but barely. The top speed run was done before I had this set up. It didn't get hot at all even with no water cooling.
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I put a shinko 241 2.75x18 on the 22" BMX rim on the front. It's heavier but it's much better. The bike handles better and I don't feel the sidewall folding on sharp corners now. I'm loving that tire! It was a little tough to get it on the rim with the big motorcycle tube in there but I got it on there and the bead seats well.
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I also switched out the wheel setup for this pit bike wheel. Same tire from the old wheel. It's a little heavier but not by that much compared to the 20" BMX rim with the moped hub, although that's not taking into consideration the weight of the caliper that will go with it. Originally I planned to use the freewheel on the moped hub for the pedals but my plans changed and I no longer needed it. This disc brake setup should be better than the drum brake on the moped hub. This thing needs all the braking power I can get. I didn't start fabbing the caliper bracket since I was working on that blue f150 in the background this weekend. Ball joints and suspension bushings ate up most of my time. I also switched to a 420 chain since the pit bike sprockets are all 420 or 428. I'm planning to do some experimentation with different sprockets. Originally it had a 22 tooth on the motor, 40 tooth on the input of the jackshaft a 19 tooth on the output of the jackshaft and a 31 tooth on the wheel. Now it's 22,40,18,35. Very close to what it was with the old wheel setup but I have a lot more options now that I don't have to modify sprockets to fit the wheel. The sprocket I modified for the original wheel was slightly off center because I couldn't drill the holes perfectly. The bike feels smoother now and is also quieter. I do miss the look of that giant 530 chain though 😁
 
A couple videos of the bike from my backpack strap mounted GoPro. I'm not real good with it yet. The angle kind of sucks at certain points.
I kept it around 30mph In the second one because that's as fast as the motorized bicycle(aka the brapsicle) goes.

For the record, I don't typically ride this on trails meant for normal bicycles for obvious reasons. In this case we felt it was safe because the trail is flooded and, generally, nobody goes down there when that happens because the end of the trail is the lowest point and ends up under 4-5ft of water.

Since the last post I've added a few things to the bike. It has a front fender, turn signals, rear disc brake finished, paint, the battery is sealed with RTV and coated entirely in flex seal, removed coolant flow indicator and installed coolant reservoir instead, and added box like structure on top of the fairing/cover for the switches.
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Those last two pics are from the day I painted the frame. The cooling system and brake caliper are not present.

I made the rear caliper bracket out of the thickest flat stock they had at Menards. It has a bushing welded into it and the axle goes through it. The part that extends forward has a slot in it that engages the big pin on the inner part of the swingarm. It can slide forward and back with the wheel to allow adjustment of the chain. The caliper is a front caliper for a Honda application.

The swingarm will be painted at a later time. I may need to weld something to it first. That's why I didn't bother taking it off or masking it when I painted the rest of the frame.

I've been searching for new forks. I think they need an upgrade. These are the $250 knockoffs from AliExpress and I don't totally trust them. The tubes flex somewhat and it makes me nervous. Is that normal? I've been trying to find some trials bike forks or something along those lines. Something stronger but still on the lighter side weight wise. Provisions for dual brake calipers would be awesome too and I see a couple mountain bike forks that have that. I think two of the Magura calipers would be sufficient for the bike. Not sure how much beefier those forks really are though. Motorcycle stuff may be the way to go if I'm going to drop the change for nicer forks. It would be convenient if I could find something that would fit in the existing triple clamps(42mm tubes) but there are other routes I could go too. Does anyone have recommendations?
 
I put a fardriver nd721800 on the bike. I initially set the line amp setting to 400 amps. The belt stripped and broke when I gave it half throttle. It tore the teeth off. So I replaced the belt and set the tension extremely tight. It was still doing the same thing so I switched to a chain
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The chain was able to handle slightly more but the chain was jumping too! So I've determined that it's the amount of flex in the motor mount bracket causing the problems. I haven't done anything to strengthen it yet but that's going to be my next move. The QS138 has a ridiculous amount of torque at 400amps! The motor bracket is not thin steel but it's bending it like it's cardboard. Part of the problem is due to my low gear ratio. The chain/belt driving the jackshaft sees much more torque than it would if I geared it shorter. So, I could just put a larger sprocket on the wheel and I'm sure most of my problems would go away, however, the motor RPM stays low with the current setup and I like it that way. The motor stays very cool and it's very efficient while just cruising around at sane speeds(which is the primary purpose after all) 😉. With the chain setup I have a 13t on the motor and a 20t on the jackshaft. 20t and 35t on the wheel chain. This setup is a 2.69 ratio. The bike still pulls like a bat out of hell and reaches 70mph+ easily. I have to say that I'm very impressed with the QS138 having come from a background in ICEs and never having built anything electric like this.The torque is insane!

I also put a different seat on it which I think is much better.1000011031.jpgthis is a Chinese ATV seat. It even has a little latch on the bottom for easy removal which was pretty simple to adapt to the frame. I no longer have to unbolt the seat and it's much more comfortable being so much wider.

I have a shinko 244 for the rear as well. Although I like this street tire a lot and it seems to be lasting, it is utterly useless on dirt or grass or anything other than pavement. I guess that should have been obvious to me when I bought it but I didn't forsee the potential situations where I would actually want to ride on other surfaces. Now I do so I'm going to try the shinko out. I hope it does well on wet pavement. That is my only concern about it. The street tire is excellent on wet pavement.

I'm pretty sure the extra torque has loosened some of the spokes on the rear wheel too. I never had trouble before but I checked earlier today before riding it and some of the spokes were loose. I guess it could've been a bad hit too but I don't recall anything out of the ordinary happening since the last time I checked. I tightened them and the wheel is still mostly true although it has never been perfect and could actually use some work. It's not a high quality wheel. Just a generic Chinese steel wheel.
 
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I'm pretty sure the extra torque has loosened some of the spokes on the rear wheel too. I never had trouble before but I checked earlier today before riding it and some of the spokes were loose.

It's not torque. It's not impact. It's that the spokes are too thick, and/or the tension wasn't turned up high enough to begin with.

Most Chinese motors are laced to rims with spokes that are way too thick to maintain tension under ordinary riding loads. There's no remedy except to relace them with thinner spokes.
 
Haven't updated this thread in awhile. The bike still isn't 100% done. It's starting to cool down here and winter will be here soon. I've decided that it's probably best not to try and ride this in the snow. I'll probably put her away for the snowy months.

Updates:
Made a stronger motor mount because the old one bent/twisted from the torque.
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This is the old mount. It's clearly not strong enough.
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The new one isn't adjustable and it's made from much thicker steel. I have zero flex issues now!

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Constructed a new cover for the wiring and the larger controller.
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I rode it to a local flea market and found the bat emblems there. The guy selling them had a ton of different shapes he cut out with a plasma cutter. He was selling them for $1 a piece. I had to grab them since the "bat cycle" name has kind of stuck with the bike now.

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I put fastace forks on it. This meant that I had to get rid of the bicycle wheel on the front. I couldn't get the bigger caliper to work with the bike hub easily. It needed a better brake on the front so I put a 17" pit bike wheel on it with a shinko 244. The scratches you see in the black spray paint as well as the bent chainring are from a small accident I had a couple weeks ago. I gave it a little too much coming out of a turn in the rain and low sided. I wasn't severely injured. Just some road rash. I was wearing the new helmet I bought a couple weeks prior. The bike was not damaged much either. The pedals act like frame sliders. These forks are a vast improvement over the old ones. I feel much more confident in their strength as well.
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I put the same Honda style caliper on the front that I have on the rear. I had to fabricate an adapter. It still needs a little bit of smoothing on the corners and paint. You can see the yellow paint marker still haha. No more brake fade when stopping from 60+mph.
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I put a 53 tooth sprocket on the back. It has so much torque like this that I can't give it full throttle from a stop. It will loop. Easily does wheelies with this setup. I think it's too much though. It still gets to 83mph like this but there is much less torque on the top end. The motor gets too far out of it's efficient RPM range. I have another sprocket to try when I put the shinko 244 on the rear. It's a 41 tooth I believe. I think that will give me a happy medium between the super low gearing I had originally and the gigantic 53 tooth.

Just a few pics of the bike I took at a park the other day.
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Chalo, I think you are dead on with what you said about spoke thickness and tension above. When I got the new wheel for the front I went over the spokes and made sure they were all tightened properly and the wheel has stayed true so far. With the rear wheel I only gave the spokes the squeeze test but I don't think that was enough. The aluminum bicycle wheels I built for it originally took many very hard hits(nasty railroad tracks around here) and never skipped a beat. Even with the thinner bicycle spokes. Very strong wheels and lightweight compared to these steel ones.
 
It's not torque. It's not impact. It's that the spokes are too thick, and/or the tension wasn't turned up high enough to begin with.

Most Chinese motors are laced to rims with spokes that are way too thick to maintain tension under ordinary riding loads. There's no remedy except to relace them with thinner spokes.
Do you know how I determine the condition of the spokes on my rear wheels with 12 kg motors? I hit them with a small screwdriver like a Romanian musician hits cymbals with hammers and determine by ear the spokes that need to be tightened, this is the most accurate way to maintain the same tension of the spokes, you will not find a more accurate one:D.https://www.youtube.com/watch?v=N63gikqYyWI
 
I hit them with a small screwdriver like a Romanian musician hits cymbals with hammers

Cimbalom! What a cool instrument. I knew a guy in Seattle who was a formidable beast at playing his.

and determine by ear the spokes that need to be tightened, this is the most accurate way to maintain the same tension of the spokes, you will not find a more accurate one:D.https://www.youtube.com/watch?v=N63gikqYyWI

That's a very good technique for discerning relative tension between spokes, but there are so many factors that affect pitch that it can't tell you really anything about absolute tension.

Even when all the parts are brand new, the components in a wheel are never so perfect that uniform tension results in the wheel being true and round. It's the discrepancies (hopefully small ones) in tension that force the rim into its correct shape.
 
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Do you know how I determine the condition of the spokes on my rear wheels with 12 kg motors? I hit them with a small screwdriver like a Romanian musician hits cymbals with hammers and determine by ear the spokes that need to be tightened, this is the most accurate way to maintain the same tension of the spokes, you will not find a more accurate one:D.https://www.youtube.com/watch?v=N63gikqYyWI

I've never seen anyone play one of those. That's awesome and I loved the song he played at the end! Thanks for putting that link in here it made my day better.

That is exactly the method I used. Some of the spokes on the new front wheel were very loose. I tightened them all to what I felt was slightly looser than perfect using that method, then went around the wheel tightening a spoke here or there to get the wheel as true as possible. I did it on the bike with the front wheel off the ground, using zip-ties as my reference points. Rode it, then trued again. It was already very very close to true when I got it but the tension of the spokes was all over the place. I haven't had any issues with it yet. With the back one, I squeezed them and they all felt tight enough. It was pretty straight, so, I just left it. After a few rides I noticed some loose spokes and that the wheel was wobbling. I have since tried to true it up again but it's still pretty bad. It causes some weird oscillations at higher speeds on certain roads. I'm probably going to replace it. I want to switch the rear hub to a wider one to allow more clearance for a bigger tire. As it is right now, a wider tire would come too close to the chain. I'm having difficulty finding a hub that will work well though. The main problem is the 15mm axle. That's an uncommon size for motorcycle axles. Most of the hubs I've been finding in my searches have 20mm or 22mm axles. I may end up buying one of these hubs and swapping out the bearings to fit the 15mm. I need to do more research to find out if that will work the way I'm thinking it will. Plan B is to re-lace the hub I have with a dish and use different spacers to move the sprocket over. I've yet to do a dished wheel though. It seems challenging.

I put new lights on it last weekend. The white circles and the cross shape are DRLs and also change to amber for the turn signals. I felt like the small turn signals on the fender mount weren't getting peoples attention.
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I also ordered turn signals for the rear as well as more brake lights. I was nearly rear ended by a woman on her cell phone in a rural road just outside of town. I was in the traffic lane, about to make a left turn and I could see that she was not slowing down despite me signalling and lightly squeezing the brake handle just enough to illuminate the brake light. She was looking down. I pulled over onto the shoulder before braking and sure enough she didn't see me until what would've been the last second. Although I was totally out of her path by this time, she slammed on her brakes and pulled up right beside me where I was rolling at about 5mph to give me a startled shrug and an exaggerated look of confusion. Cell phone in hand and child in the passengers seat. I'm so glad I bought those mirrors. My brake light has amber turn signals too but I don't think they are visible enough in bright sunlight. I'm going to make a mount for the new ones similar to the one it has in the front right now. A piece of tubing with nuts welded on the ends and ground smooth. I am always vigilant of what is behind me but imagine if there had been another vehicle behind her when she abruptly slammed on her brakes in a panic the way that she did. Could've been a bad situation for everyone. I was disturbed by the incident because, although she seemed to be on her cellphone and not paying attention to what was going on in front of her, I can't help but blame myself as well considering that I'm knowingly riding an unusual vehicle with possibly inadequate lighting installed. I can do more to be safe.
 
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