View Full Version : Electric Dirt Bike Project - First build

10 June 2011, 0811
Hello All

Quick introduction: I'm a retired science teacher, now a stay at home dad who got a GREAT deal on a motor a few years ago and has finally started a project that may or may not pan out well, but has been fun so far.

Bike: 2002 YZ426F
Motor: Advanced DC 140-1-4005 series
Controller: axe 4844

Stage 1: (complete) Design a drive train and rolling chassis that accommodates the right side drive of the motor and gives about an 8:1 ratio to give lots of low end and top speed around 45mpg ($450 or so all in)

Stage 2: (complete) With drivetrain in place hook up a battery and ride around to see if drivetrain is realistic and will holdup. Note: power system is as follows-- one used car battery wired to motor through ar starter solenoid off an old chrysler and activated by a momentary button on the handle bar (old kill switch reverse wired) ($20 for msc wire)

Stage 3: (in progress) Find a battery solution that doesn't kill me financially and wire up the controller. ($300 so far for controller)

Goal: To have a fun bike that can roost around my yard. If I can ride for 10 min in the morning before my kids wake up I'd be pretty happy.

Right now with 12 volts the bike has on and off mode and can cruise around the yard at about 10 mph. We have quite a bit of elevation at our house so it can hit 35 on the down hill before I have to make a turn.

No need to comment on the backwoods engineering of my power system and battery "hammock".

Right now my questions will be around battery technology and range (more measured in minutes than miles).

THanks for all the info on the site and in the forums.

anyone give me a quick lesson on attaching a photo and I'll do that soon.

10 June 2011, 0838
Welcome! post some pictures, definately!

click "go advanced", and go to "manage attachments" at the bottom and upload a pic or two.

How "heavy" is that motor? I'm not familiar with it, but an approx weight will give me an idea on the motor size.

Sounds like a great little project.

10 June 2011, 0919

Advanced DC, #140-01-4005, 5.5", 24-48 VDC

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Advanced DC 140-01-4005 Motor, 24-48 VDC, 5.5" diameter by 11.16" long with a .875" diameter keyed single shaft 2.5" long, Not Reversible, clockwise rotation looking at shaft end.

Our most popular brand of DC motor. A wide variety is available. The largest are commonly used for on-road electric cars and trucks, as well as 200+ MPH EV motorcycles and...furniture!

Current Ratings: 60 amps continuous, 80 amps for one hour, 350 amps peak

Horsepower Ratings: 3.8 hp continuous, 5.1 hp for one hour, 17 hp peak

Weight 38 pounds

All ADC motors use class H insulation (180 degrees C)


10 June 2011, 0938
That's a perfect motor I'd think. Seems a lot like a K91 motor but smaller diameter. Good HP and current capability.

10 June 2011, 1019
so here are a few photos of current stage.

10 June 2011, 1115
Welcome Ibjed. I love the belt primary drive. Where did you get the larger pulley?

10 June 2011, 1354
The the larger pully and the one that may or may be permanantly attached to the output shaft both came with the motor from the previous application on an electra motorsports go kart. Then Northern Tool came through with a sprocket adapter that fit perfectly inside the larger pully.

17 June 2011, 0758
I just picked up my last major component for this version of the project. I went with 4 hawker AGM 42ah batteries. I know agm have some pros and cons, one of the cons being they require more care in charging. Could someone point me in the direction of some info on charging specifics and/or recomend a charging solution? ie individual chargers, series charging, golf cart charger, etc. I am looking at quality charge first priority, cost as a close second and not giving much priority to time to charge. Thanks

17 June 2011, 0825
Just use individual 12v smart chargers....most important thing is to never let the bike sit at low soc. If you're not riding it....it should be on charge/float. My batteris lasted 3 years and 2800+ miles and are still going strong....now being used in my buddys trolling boat. I had (6) 35ah AGMS and used (3) 5ah 24v scooter chargers. AGM's don't die easy....but can easily be killed!

17 June 2011, 0841
by smart charger, do you just mean something that charges fast then goes to float when charged? Like a $30 charger from auto parts store? or something more specific?

Also are there precautions as far as heavy use right off the bat? a break in period etc?

Thanks DRZ400

17 June 2011, 0854
Yes, here's where I got mine and what I used.. http://www.tempestbatteries.com/html/bc-24-5000f.html

I didn't break mine in....ran all the time till I hit LVC or not, then put on charge immediately. My (3) chargers were mounted on board (very light and reliable).

17 October 2011, 0026
BIKE IS DONE! well, assembled only to be disassembled tomorrow when the rest of my heat shrink comes in then disassembled again to paint the frame and probably two more times just becasue I forgot to do something.

Finished at 1:30, rode for 15 min, parked it then started tightening everything that came loose. Bike was an absolute blast, sideways most of the time, quick, and totally silent. Even took it through the woods a little in the moonlight, then decided I better not tempt fate too much.

Have a question on precharge resistor: if it's wired across the relay(as in my wiring diagram from alltrax, is it always drawing power? if so how are others wiring to avoid this? (btw I only have a manual disconect, no relay but I still have a resistor to resist large inrush/arcing)

warning: I'm horrible with timely pictures so ya'll might have to wait abit.

19 October 2011, 1144
Here's a quick video to show the jist of the project. Lots of buttoning up to do yet. I came in a little over budget, but $1300 including a welder to modify the frame isn't too bad. Let me know if there are issues viewing it.


19 October 2011, 1208
here's another: http://www.facebook.com/photo.php?v=10150425306166420&ref=notif&notif_t=video_comment#!/video/video.php?v=10150425344841420

19 October 2011, 1238
Man that's hysterical! Between your pit crew and the dog chasing you all over the place, I busted a gut. Looks like a BLAST to ride, too! Congrats!

19 October 2011, 1317
Nice work Jed.

Love the video. I'm guessing your wife is not going to let you do the babysitting anymore.;)

19 October 2011, 1622
dude...i want one

19 October 2011, 1703
dude...i want one

yup. Think I'm lookin' at my next project. :cool:

19 October 2011, 1721

19 October 2011, 2122
Looks like some ridiculous fun Jed, welcome! Bravo on the install. http://www.animateit.net/data/media/august2009/clap.gif

For the "Precharge Resistor", the draw in minimal. However, if you want it completely off, you can use a relay to turn the Precharge off and on. What I would technically suggest, is to use a 555 timer in monostable mode and on pin 3 of the output, attach a transistor going to 2 relays (one relay for your precharge, and another for your throttle).

If you still have the key ignition with wires, you could attach the ignition to supply power to the 555 timer and associated circuits.

Ask a lot of question mate, this forum is full of EV enthusiasts.

Welcome again,

19 October 2011, 2130
Great job! Love the comment about needing to up the amps on the controller. MORE POWER!! :D

20 October 2011, 1241
Here is the youtube version of the video:
Hopefully I'll get it on the scale for weight, straight away for top speed, and a longer trip to know range this weekend.

23 October 2011, 1605
OK, so I've had a chance to do some testing, reconfiguring, tinkering etc and I've got some experiences to relate, some questions, and some catastrophes in the works.

1. Ride in the dark: during an early ride in the middle of the night (no lights on bike and in the country) I look down and there is some blue arcing in the brush area of the motor. I wasn't suprised and am currently assuming that that bit of arc is "normal" since I see it on drills and other stuff from time to time. I would just like affirmation if my thoughts are correct.
2. Range test: I got a Watt meter thingy from the library and recorded 1400wh to get my pack charged up(all bats in upper 12's), then did a 1 mile loop. I got 2 really good laps in, then one moderate loop and got real doggish on the 4th. went 4.8 miles and was nearly completely dead. 3 of 4 were about 11.8-12v but one cell was way down below 10(came up above10 after sitting for a while). my conclusion is that i have a bad battery (they were used) and figured I can still have 15-20 min of quick fun on that charge. I charged upeverything with about 1600wh.
3. Today's catastrophe: playing around my property riding some trails, climbing some hills, just generally testing some stuff out. Under heavy throttle (axe controller in stock 1/2 throttle setting), bike had total loss of power. I stopped looked at all connections, controller, etc. Green light was still on, gave some throttle and a very small amount of movement. Pushed bike back to garage and looked closer and smelled sulfur. applied throttle on stand and got clicking noise in motor and alittle movement. Did a quick tear down and removed all batteries incase there was a leak or something. The low battery seemed to be the one putting off the odor. They are Hawker Genesis 42ah agm batteries. I am assuming that bat is to blame for power loss, but have not had achance to test controller or motor. any thoughts on what's happening. Thanks in advance guys.

23 October 2011, 1620
Sounds like maybe the battery vented. I bet it's dead. Could you get a replacement and hook it all back up?

23 October 2011, 1941
Why not bypass the suspect battery to verify the failure? Sounds like your controller and motor should both work at 36V.
Was there a fuse protecting the controller? (Usually the AXE's come with one)

23 October 2011, 2206
There shouldn't be a lot of arcing. Put it on a stand and run the motor at about 1/2 throttle - if you still see arcing it either needs new brushes or the commutator needs to be turned (or both).

If you can get inside, take a look at the commutator and see if it's discolored. Copper colored or light brown is OK. Black streaks are bad.

Inspect the brushes - they should be smooth. If they're pitted you're getting too much arc.

When you say you heard clicking in the motor, was is turning and making a faint, regular clicking near the brushes? If so, that's another indicator that the commutator is out of round and the brushes are chattering.

Batteries - same as stated above - that cell is almost certainly bad and not letting current through.

24 October 2011, 0620
zoomsmith: already workingon wiring up 36v test, and all circuits are fused.

podolefsky: the clicking was while the motor was trying to turn kinda dull quiet maybe like 5 hz. Kinda like a dead car battery trying to start.

Another question: As I get this project cleaned up, how much of a shield should I build around my motor to protect it from front wheel crud? I'm thinking I'll want it fairly protected but not fully encapsulated to dissipate heat. Maybe a "hood scoop" kinda thing to bring some air to it?

Thanks for thereplies everyone. I cant say how valuable this community has been in info/ideas.


24 October 2011, 0827
how many amps are you drawing from those hawkers continuous? peak?

Fab man
24 October 2011, 0830
Your toothed belt might be cogging(slipping teeth). Try tightening the belt and checking again. You might have too few teeth engaged on your small sprocket(9 to 12 is usually the absolute minimum recommended) BTW, is it welded on to the motor shaft!?

It looks like a carbon fiber belt, with the blue lining. What is the pitch and width of the belt?

As far as protection for the belt drive: the belts are pretty tough. I've felt and heard small twigs and rocks get "digested" by the toothed belt drives I've used on bikes with apparently no ill effect. This can't be doing them any good though, and small rock chips embed themselves between the belt teeth, cutting into the tension cords. So, you should make a tight fitting cover to protect the drive.

Welcome to the EV grin club!

24 October 2011, 1436
Frodus: controller is programmed at 200A max, I don't have a meter, but i can feel when it draws hard under acceleration and feels pretty light up to speed. I have it geared low enough, that it doesn't accelerate for long, I'm either up to speed or the tire is spinning.

Fab man: teeth aren't slipping, the noise wasn't near that loud or obvious. I'll check how many teeth are engaged. I was concerned with it being too wide of an angle over the small sprocket, but if the belt is just remotely tight there is no issue. The belt is a gates polychain GT (sprockets had that stamped into them) and BTW it is welded on (not my doing). I planned on making a tight cover for the drive side, but still wondering how much air the brush side of the motor will need.

Update: hooked up 36v and controller and motor seem fine. It is weird that I charged the "bad" battery up and it charges up all the way, but drains so much faster than the others then inhibits them. I'm going to do some range testing at 36V until I can get additional batteries. in a darkish garage I'm not seeing any arcing, I only saw it in complete darkness, but I'll do some more night testing and pull it apart to take a look at the brushes.

24 October 2011, 1454
Update: hooked up 36v and controller and motor seem fine. It is weird that I charged the "bad" battery up and it charges up all the way, but drains so much faster than the others then inhibits them. I'm going to do some range testing at 36V until I can get additional batteries. in a darkish garage I'm not seeing any arcing, I only saw it in complete darkness, but I'll do some more night testing and pull it apart to take a look at the brushes.

That's exactly what I would expect with a bad battery - loss in capacity. It will charge up and drain faster than the others. When it is discharged, it will have a very large internal resistance, blocking current flow through the system.

You should be able to see the arcing in a dark garage. If you don't it's probably OK...check the brushes anyway though.

24 October 2011, 1459
how long do you draw those 200A

Not sure if those batteries will take that, it could have been permanently damaged.

Were they used before you built the bike?

25 October 2011, 2020
not sure how long the 200a runs, but I wouldn't imagine more than 10-15 seconds at a time. . batteries were used but an unbeatable price, so took the risk. I think I can get more though. From what can see in Hawker's info, they should be able to handle pulses at fairly high current. What would you guess a 48v bike traveling at 3/4 top speed on level ground draws for current? I was thinking fairly low(compared to during acceleration) but I have no real idea.


09 November 2011, 1455
in advance: thanks to everyone for putting up with all the questions from all angles.

I've had the bike set up in 36v mode since I vented one battery but haven't ridden much (fall in mn means get the house ready for winter and stockpile your firewood). I would assume that in series, lead batteries would all discharge at a similar rate and stay within a similar voltage range. Of my 3 in series, one is consistently lower after a bit of riding. My guess is that, like the one that vented, it is on its way out and is showing its age. I'm not too worried as I have established a supply of more of these batteries, but wanted to throw it out there to see if I'm on base with my assumptions. If anyone sees any reason for unbalance in my batteries other than one is going/gone bad please speak up.

If any of you are going to say you should stop buying used batteries, or go lithium, or anything along those lines, I am aware of the disadvantages of used batteries but I'm getting them for less than the local scrap yard will pay me for them. that being said, I was able to ride a wheelie with a full charge today, roosted up some really steep hills, and snuck up on some deer and amstarting to think I'd much rather be out riding than working out kinks. oh and MN passed legislation that will make it easy for me to get this bike highway licensed so if all kinks are out by spring, look for supermoto edition.



08 February 2012, 0720
a couple questions:
1. I'm building crud protection for my motor and am wondering how much ventilation does the motor need on the back end? Can I fully encase it with an airspace or does it need flowing air past it?

2. @ Frodus: you seem to think my Hawker batteries shouldn't be putting out so much current. Are you saying this is true for all agm batteries or just this particular model/type? Any suggestions you (or others) have on this is valued.

Thanks guys.

update: My house is on jacks so the bike's not getting any attention right now.

08 February 2012, 0919

Enjoying your build! Do you have a cost sheet and time that you can post? BTw did you house have a flat?:cool:
Los Angeles

08 February 2012, 1044
Motor $40
Rollin chassis $250 ($400 minus radiators and motor mounts sold on ebay)
Controller $300
jackshaft and bearings $75
chain and sprockets $75
belt $25
throttle $50
batteries $80
chargers $120
Fuses switches diodes etc. $100
Wire ends heat shrink $75
Steel and welder $100

By time, do you mean time i've put in? if so

Research: 4535 hrs
Just looking at it: 324 hrs
building: about 40hrs

I got stuff all over the place but had good luck with craigslist (searching adds and putting up wanted adds), surpluscenter.com, and northern tool. I have developed a relationship with local autoparts store that crimps my lugs on my wire for free.

hope that helps

08 February 2012, 1048
oh,and if you actually care, the center wall in my 100 year old basement lost about 3 inches to rot over the years. That means I've spent months with the basement a complete mess (no room for workshop) slowly lifting the house. But I'm about a weekend from being done with that project and back to the bike.

08 February 2012, 1523
Good to see you back at it. I hope the house is straight again.