Need new motors? break a chain? brakes not work? swapping out pinions or sprockets?

Moderators: robnewyork, bassiclyLouDog, gameboy

By david coffin
I have an ezip 750. used-- i had no idea of how many miles had already been put on them (they don't come with odometers). works great for my 260 pound self, and i put several hundred more miles on it. the main shaft bearing now is messed up. researching the motor, and motors in general, and properties of the bearings themselves used in the motors, leads me to conclude that heat, more specifically, friction heat, has partially destroyed the bearing.

This, after reading this post: viewtopic.php?t=1365

I find there are ceramic bearings, both full ceramic (the balls, and the races, are entirely ceramic), and hybrid ceramic bearings (in that the balls are ceramic, while the races remain steel). as far as heat, the ceramics do not tend to produce heat, and do not expand, as steel does, under heat. there are differences, as shown by the manufacturer, such as the possibility of shock loading being a factor. riding on footpaths, rather than the paved road, often leads to shock as in going over bumps and uneven pavement. Steel is good at that, but i figure that when the whole thing is hot, the steel races and the bearings being a steel/steel/steel sandwich of sorts, expands into each other and can cause deformation of the balls, due to heat increasing malleability of the metal.

the current motor and brushes have tons of life in them, it's the excessive heat caused by the bearings dragging the motor and drawing more current up to the amperage limit of the controller, causing frequent shut down, even on mild grades.

I am faced with a choice: buy a brand new motor, or purchase replacement bearings for my current motor, with the ceramic replacements being the solution to the heating and longevity issue. I also find that ceramic bearings, frequently require quite little lubrication (although, lubication is ALWAYS a positive thing) while steels, even sealed ones, would still demand periodic and more frequent lubrication for maintenance.

ideally, but not agreeable with my billfold, i would choose to buy a brand new motor, and replace the stock steel bearings with ceramic bearings. this should increase my range and the life of the motor dramatically, i imagine.

there, now i have a sub-choice. full ceramic bearings are in the $100 to $150 usd range, while hybrid ceramic bearings are half that. i have not been able to get an answer, whether the full ceramics are hardy enough for daily use, and offset the negative benefits of the steel races expanding under heat. this is the website I found the ceramic bearings ( ... i3n4-14589) , and I also find the bearings used in my motor are stock sizes for skateboarding applications, as well.

the main bearing is 6000z and the commutator support bearing is 608z, also used in skateboards and such.

so much information, and i'm hamstrung by my billfold limits, heh.

maybe some chap can test this theory for me.

--david, USA

By robnewyork
my solution , these motors are generally considered disposable.. you either A , replace it with another currie, B , vent the motor to dissipate the heat ( something all the curries and unites are horrible at compared to indutrials and rc brushless motors.
By Laundrydude
There are many grades of sealed bearings. I think there is more heat transferred from the motor than generated from the bearings. I use a thermal camera when inspecting things that heat up. You could try a sealed bearing like a 6000-2RS. The z bearings have a non contact shield, but the seal may take the heat ok.
robnewyork: excellent! 24 volt 1000 watt motors are hard to find, and this one is definitely on my next allowance.

venting, involves drilling holes and stuff, and my skill is redneck-grade. not to mention, dusty and dirty places, such as SmogLA would be detrimental to the motor, should the tiniest pebble of dust make its way inside. I have an idea of a continuous lubrication scheme, using recirculating mineral oil (since it's non-electrically conductive), or perhaps just loading it up as a differential-style, in which the oil is in a sump, and the bottom of motor splashes the lube up into all the nooks..
By robnewyork
well , if you wanna go 40 plus MPH with good torque , u only need 1 motor and controller combo. ... 2XfUO6SbLA ... 301a9.html

run this combo at 36 v with the 17tooth sprocket from surplus center or ebay.. get 3 decent size batteries and top speed would be 37.7 mph with good acceleratio
tell ya tho, that currie motor of mine is still going strong, even with that ronky bearing. just did 20 miles the other day (I tripled my 24 volt battery pack to 36 amp hours, that's 3 banks of batteries in parallel)
By robnewyork
either way , when you replace the controller on that model , you have a lot of wiring to do.. simply because the way the on off switch runs 2 different things.and the fact they use bullet connectors off the controller.. in light of that, id go 36v 50amps and really have the scooter moving
so, after much research, here's my shopping list for my Harley. ... ocket.html ... uct_id=170 ... duct_id=77 ... i3n4-14604 ... i3n4-14589

the last two are gonna go in the 900 watt motor, and should enable me to go on marathon non-stop runs without extra heat caused by the steel bearings being replaced.

maybe. i'm concerned with shock loading resistance to cracking. worse things have stripped and broken by hitting a high piece of broken footpath...

welcome all thoughts, cheers
well, well, well.. currie sure had me by the nose. i'm maintaining the axle bearings on the wheels (clean, wd-40, etc) and lo and behold it hit me- it's the same size and type of bearing that is the main shaft bearing in the xyd motor on my ezip 750.

6000z. that really simplifies things, for me. no one knows what i am talking about when i say bearing this size and dimensions, but now i know i can just order -part- axle bearing- currie wheel, front or rear. exact same animal.

doy! so now i can take an axle bearing, off the wheel, that has had much lower mileage in terms of elapsed revolutions, and swap out the bearing in the motor that has had millions of revolutions on it in ratio to the wheel bearing.
robnewyork: i ordered what i imagine is the yk43b, url: ... 1489166886, you did tell me the mini yk43 is for 36 volts and up. the motor i got was the 900 watt 24 volt beast you referred me to at right out of the box, before installing it, i could see a huge difference with the old and the new motor-- the new motor, with it's brand new magnets, cogs hard by hand. my old motor, on the other hand, turns easily by hand, leading me to think the old magnets were just losing or demagnetizing over time due to age and use. the armature and brushes in the old motor look in good shape, still, so i theorize that if i just replaced the old can (that has the magnets glued to the inside of it) with a new can, as well as replacing the bearings, would make it a good quality refurbish.

finally, a hobby i can die for! so cool to go and cruise everyday with only 5 cents of electricity, especially when the lawmakers are talking ANOTHER gasoline tax hike, here in california. pfui.
By robnewyork
u wont feel a difference with the 900 watt till u change the controller.. maybe a slight difference,.. i think the yk43b and 900 watt will be faster than your worst nightmare, get a helmet asap..
oh, yeah, big difference. the new magnets give me more grunt, even with the current controller i have, so now i can get up my driveway without switchbacking. i've been out this afternoon testing and riding trails near me. major difference. top speed is the same, as expected, but, uphill grunt is major. the controller comes... tomorrow! yee hee. runs noticeably cooler, too, compared to the old motor. think it'd be a candidate for the impossible uphill climb in Belgium ? see this at ... climb+2017
this is stock gearing, with knobby tyres i got after the stock ezip street ones (that were bald to begin with) gave out. i know top speed won't change, but by fast you mean how quickly the motor ramps up with the beginning creep of the throttle, yeh? and that's you in the video? tiny wheels
ought to be similar to my experiences with dirt bikes. they tend to have twitchy throttles, too. hm, so i can take a leaf from the tractor pulls and add weight to the front of the scooter, or add a wheelie bar. heh heh
yarrrrrr....... got my new yk43B. wired it in, quick-n-dirty, and sat on it. started twisting the throttle. buzzzzz hummmmm twisted a bit more, started off. this is exactly the kind of controller that i expected! the old controller was so annoying, any time i throttle down, and then immediately throttle back up, it takes forever to ramp up. this new one, no waiting, precise acceleration on demand, immediately. woo hoooo. dont even need to switchback up the driveway no mo. twitched a bit more, promptly blew out a 40 amp ATO fuse. put a slug in, kept going, to the pep boys. top speed is the same, but, the grunt and acceleration, suits me perfectly. its back in pieces now, and im doing a redesign and rewire newer wiring connections and all. its been ages since i been so focused. next plan is disc brakes for the rear wheel, fix the missing safety circuit for the power cut off for the controller that the brake switch wiring is for.. and above all else, ride or die.
you want my sloppy work in progress? and, say, does tye yk43b have a low voltage cutoff? got some scares, thought i blew something out once, and another time thought my chain jumped teeth or something.. got back home after a hard workout of hills and trails and shopping, and my arrivall voltage was 22.7.
getting serious wheel lift now.. room in there for one more bank of SLA batteries, eventually, for 24 volts and 48 amp hours. and THEN ... hmm. rear brake sorely needed.. thats next for now. and yes,i cut away the bottom battery traynow i have clearance for buckled footpaths and going up and down curbs without dragging. and the dirt trails, too, heehee
20170419_193350.jpg (25.03 KiB) Viewed 2730 times
By robnewyork
cool! lotta amp hours on that thing.. what kind of range are you getting ,and how are you monitoring the low voltage, I assume with the yk43b cutoff?? You might wanna get some all weather protection on the controller.. maybe a small platic toolbox ??
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