GCinDC's Zooma Ty Rod II go kart conversion

GCinDC

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Jan 23, 2009
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Washington, DC
kids (ages 10, 8 and 5) have been begging for a go kart...

i'd gotten free off CL a schwinn fs missile scooter that needed batts, and since i really didn't plan on riding as is decided to cannibalize for the project (borrowed pic):
158159530_--missile-fs-black-red-silver-electric-scooter-with-.jpg


i cut up charlie's old bike that had the same size wheels, planning to combine w/ scooter parts, but gave up on that idea when i realized how much of a pain it'd be to do the steering w/ two diff forks. we toyed with other ideas as well... haha
20150711_184618.jpg


so i started hunting around for old go karts/frames.

i found a nice small zooma ty rod ii go kart on green bay CL and picked it up while just on vaca there. as you can see by the lawn mower, it was nice and small, and i liked the brake and throttle levers on the steering, for the smaller kids:
download.jpg


the previous owner had plowed into something and bent the frame at right front wheel, so i fixed that, and the kids wanted to paint it.
[youtube]Ba-gkDhlBsE[/youtube]

20150806_101256.jpg


the previous owner said it ran great, but just before i showed up, he told me the pull start broke ("just a $15 part"). i fixed enough to find that it wouldn't start after 15 pulls, and that was fine since i planned to convert it anyway. strapped it on top of the minivan for the 16hr drive home:
20150808_095141.jpg


the trickiest thing so far has been the motor mount. as you can sorta see in this pic, the scooter motor was mounted to a big flat piece of metal that also served as the chain guard:
20150711_105700.jpg


i decided the easiest thing was to cut up that chain guard mount, and bend it to mount off the vertical bar that the old engine mounted to, shown here held by a clamp:
20150811_072044.jpg

20150811_072031.jpg


so that's where i am now. i'll add attach another bar or two from old horizontal engine mount bar to stabilize the motor laterally.

it's a 24v 26A controller and it spins the wheel surprisingly fast with no load. i won't be surprised if i have to put a larger chain ring on the wheel tho, to lower the speed and up the torque. i was very happy to see that the kart and scooter used the same size chain! :p

oh, and i've got to swap the motor leads so that it runs forward, with the motor in this position. i spent some time researching it yesterday: can a brushed (currie) motor run in reverse? i tested it under no load, and it seems to work, although it doesn't spin freely forward when not powered - has some resistance, while it spins freely the other way... all feedback welcome! :mrgreen:

ps. testing w/ lipo, but might end up getting lead batt for safety/charging convenience for kids...

and once i get it running, i'll have to worry about where i let the kids ride it in our neighborhood... got a safety flag tho! :mrgreen:
 
so close and yet so far...

rigged up the main motor mount:
20150811_173823.jpg


tested it out, and runs great in reverse:
[youtube]lNLmnTjoUls[/youtube]

so i then swapped the motor leads, but it freewheels.. :roll: i didn't notice this when i tested it out before!
[youtube]FBsxQ0nePq8[/youtube]

suggestions!?

i guess i gotta take that cog off and see what's going on. hopefully i can flip it??
 
Hillhater said:
Sprag/roller clutch
that's it! never seen anything like it... here's a vid after i got it apart (pardon the kids in background)
[youtube]JsWt5751c3U[/youtube]

seems easy enough to flip and that works. gotta move my mount 1/2" back, but that's just a couple holes, and it's going to be even more stable.

btw, i started to mount it on the wheel, but won't work w/ disc brakes (which i love!). the frame is different on each side, and i'd rather not have to weld on new supports over there.
 
flipping the sprag clutch did the trick. just had to realign motor.

kids are psyched:
20150814_184005.jpg

[youtube]5xSfMFkXeSE[/youtube]

it's pretty slow tho. probably ok for kids now so they get used to it, but it can't move me at all. might upgrade motor later, but glad i got it running like this.

just using one 5.8ah 8s lipo pack at the moment. glad i didn't buy 24v of sla! going to put 4 spare pack in parallel and see how it goes then.

there's still heaps of work tho. the brakes are crap even after i replaced all the cables with new ones. the lever is too short and it's way too hard to pull to get any power to stop it. under the seat, the brake line attached to a bar, on either side of which the right and left brake lines are attached. i might have to redo handle bars to add a longer bike lever, and maybe even throw a hyrdaulic brake on, if only to one wheel. tempted to try a foot pedal, but charlie would never be able to reach it.
 
Cool build. The closest thing I did for my kids a few years ago was hot rod an old 3 wheeled golf cart that I ran on 48v and the kids loved it until the sla (i know) batteries died.
 
.....it's pretty slow tho. probably ok for kids now so they get used to it, but it can't move me at all. might upgrade motor later,....
I dont know how that motor is set up, but sometimes the brush timing is set to run best in one direction ?
a no load current check for each direction of running might give a clue.
I once built a similar kart for my kids when they were a similar age/size. After a few years i ended up with one kart for them,...and FIVE for me ! :shock: :lol:
 
dbaker said:
Yep. Karts are what led me down the gear head path...
ever since i was 12 and saw some kids doing donuts in the infield, i was smitten. junior and senior high school were ALL about go karts for me. wish i had pics. i lived in mass at the time, and my favorite thing was getting the kart up to full speed on the snowpacked street and seeing how many spins i could do. :twisted:

the passion somehow got lost after my first couple speeding tickets in cars, until i discovered ebikes. :wink:

anyway, back to the kart. i really liked the existing butterfly steering wheel, but:
- the brake lever was way too small for the power needed to pull
- i didn't want to have to rig up an ebrake switch on that lever to stop the motor when the lever was pulled
- the accelerator cable i had running to the back to twist a hall throttle was too stiff, not enough recoil, and wouldn't do more than half throttle w/o add'l mods

so i decided to bend charlie's old bike handle bars and flip them upside down like some other ekart steering bars:
20150817_164105.jpg


20150817_164054.jpg


then let luca try out the positioning:
20150817_200713.jpg


this shows the brake lines, fyi:
20150817_202142.jpg


took me a while to figure out how to attached the new handlbars to the stem, but finally figured out a bolting solution:
20150817_234932.jpg


i paralleled 4 8s lipo 5.8Ah packs for 23.2Ah and put them in an old Zappy! ebike bag in front of the seat just to test it out. ran MUCH better.
20150817_234943.jpg


a tad slow for me, but will probably have good speed for the kids. i think i'll put a bigger chain ring on the wheel to give high more torque, less speed tho.

i'll also mount the batts on the back - won't use lipo for more than first runs. still considering AGM SLA, but might look at some lifepo4 packs.

will need to wire up battery monitors/switches etc. fog lights? :lol:
 
quite a joy to see luca's face after his first powerslide. :p
[youtube]M3mYrtxKJ8Y[/youtube]

motor got stupid hot after all this. when i could smell the windings as he passed, we took a little break. :mrgreen:

any suggestions where to find size 25 gears for the wheel? i suppose i better figure out the mounting pattern, etc? not sure how big of ring will fit with that size tire...

been looking at some bigger motors, figuring they'll manage the heat better, even if i want to keep it at 24v. big block? suggestions? :mrgreen:
 
wineboyrider said:
http://electricscooterparts.com/motors36volt.html
Go for one of the 1000w rated motors. Could probably push 2000+ in them for a short while adding cooling mods. If not maybe a bldc kollmorgen?
thanks, i've been looking at that 36v1000w motor for $169. a bit more than i wanted to spend of course, but you think it'd run fine, and esp cooler at 24v? if so, it might be the ticket.
MOT-481200.jpg

i esp like that the direction is reversible. i've checked all around and the one i'm running, an XYD-6B, is NOT, tho i'm running it backwards anyway. could be a factor?

another factor is certainly that the sprocket it drove on the scooter had ~92 teeth or so compared to the go kart sprocket which is probably closer to half that:
20150819_190827.jpg


it looks threaded w/ some extrusions, but conceivably modifiable to replace the existing kart sprocket...
20150819_190939.jpg

...if the sprocket is not attached to hub, which i can't quite tell w/o taking it off:
20150819_190913.jpg

20150819_190928.jpg


Hillhater said:
Remember,... More power needs more amps and that will need a bigger capacity battery which will weigh more.
Somewhere there is a compromise between power, weight, and cost.
i've got a 23Ah lipo on there now - haven't put wattmeter in line to see how much current it's pumping (but controller is 26A) - and it the cells only dropped from 4.00V to 3.85 after an hour of riding, and it weighs nothing, so i'm fine with that for now, and pretty much ruling out SLA for the weight and cycle life... :wink:

dnmun said:
go for two motors. one on each wheel. two controllers, and one big pack. then steer with two separate throttles. one on each side. ultimate drift machine.
that would be interesting, but poor charlie's thumb isn't big enough to manage the throttle and steer. grabs brake lever with entire hand. remarkably adaptable fellow, as you'll see soon in the next vid... 8)
 
thanks, winey. was just about to post that i also found this for $89 shipped: 48 Volt 1000 Watt Electric Motor MY1020 48V 1000W
like that it's got vents too!
$(KGrHqJHJFMFJIP9ZH2WBSZYN0eVbQ~~60_57.JPG


confused that some of the MY1020's list rated current at 20A and others 26A, so not sure how they're getting 1000W on 48v, but either way, this bigger motor ought to run MUCH cooler on 24V, right??

thanks!
 
the internet is magic.

i swear i ordered this yesterday. lol. of course the #25 cog won't show up till wednesday, via usps...

i expect it will result in an increase in performance... next weak link, the controller. :twisted: or the chain??
20150822_141431.jpg


gonna take a minute to fab up a proper mount. i kinda expected this, and that's why i didn't waste much time on first one.. time to dust off the welder i suppose and bow to thor.
20150822_141443.jpg


20150822_141504.jpg


if get a bigger wheel sprocket, maybe wheelies? :twisted:

i am a bit concerned about dust intake, since the infield is the safest place for the kiddies right now. think i should cover the one side?
 
[youtube]m4TD-ZWZg2A[/youtube]

one bolt holding the motor, thought i'd check the direction and spin up:
[youtube]LM1tDXyd7Jc[/youtube]

not that fast, but just 24v... gotta think it'll have more umph, and run a lot cooler, even if it is yearning for more juice.

if i do end up wanting a bigger controller, how can i govern it for the kids? could i rig up a circuit with a resistor or something on the throttle, so when switched from normal (no resistor/full power) to kiddie mode, the max throttle voltage would be like 3v instead of 4v? would that work? or would a resistor not be the right thing for that? just thinking ahead.... :mrgreen:

or i could just have a higher voltage controller/battery for me, but that's more effort to swap...

next job is the motor mount. i like the idea of mounting it sideways, like in the vid, on that vertical bar, but need another there...
 
ps. the wheel sprocket is 55 teeth with three bolts 33m center to center.
20150823_154159.jpg


i could get a 68 or 72 here if i wanted...

and just for my reference purposes, tires are size: 4.10/3.50-4

gear ratio calc is here: http://www.bmikarts.com/Gear-Ratio-Speed-Calculator-MPH_ep_84-1.html
gokartgearratio.png
 
thanks!

the quick and dirty battery case i had left much to be desired, so i got a pelican 1200. these cases are so sweet:
20150828_145354.jpg


more on that later. i also felt i needed a slower mode for the little ones/beginners - i really don't want anyone plowing into anything - so cut the throttle wire and added a two position switch. in one position, the throttle signal current travels through a 5k Pot, which lowers the end throttle voltage getting to the controller. so wide open, instead of ~4.3V, the highest is 3.5V. the other switch position just reroutes the throttle signal thru the switch w/o any change, so that's the full throttle mode. here testing the circuit:
20150828_142142.jpg
 
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