midsize atv conversion - will an amazon kit work?

mchrislincoln

10 µW
Joined
Jun 25, 2021
Messages
5
Hi all,
First time poster but have done all kinds of projects and really feel blessed that there are forums for pretty much any fancy and while I may not be an active poster I try to follow up all my posts with pictures and close the loop with the outcome. Anyhow here goes!

I have and 8 and 6yo daughters. They have totally outgrew their barbie jeep (only upgrade was a much larger AH 12v battery). It served its purpose but just is no fun for them now. I happened upon a 200x dinli 110cc quad (mid size) for a cnote. It didn’t run but a new carb and a few other parts later she is running. It is LOUD, STINKY (2stroke) and scary. Im pretty much a noob when it comes to quads but got a mint 1994 300cc Kawi bayou 4x4 quad a year ago and while that is perfect for me and +1 kid but the little 110cc seems to be WAY more dangerous. It is quick and small to the point I was able to lay it over myself while just screwing around. I adjusted the set screw on the throttle but its still way to squirrly for the kids. That and my 8yo is terrified of it as just idling it vibrates like hell and is prob 2x louder than my 300 kawi. It’s a bit rusty but looks to be all surface but everything else seems to be there and it appears to have solid bones (plastics not so good). Seems to have plenty of space for motor and a batteries.

So long story short, I want to yank the gas engine and convert it over to electric. There is a ton of info on this in this forum and other forums but I am finding it hard to find anything newer that deals with brushless motors. It would appear that it is best to use an ATV that has a separate transmission but this onedoes not have a separate transmission, it is built into the motor.

My question is do/will the newer style brushless motors handle the gearing that is feasible in order to make a reliable rig going directly from motor to rear shaft sprocket with a chain.

It looks like the existing sprocket on the bike is 32t tooth 428 but most of the kits I am seeing (on amazon at least) are a t8f size. I found a 74 tooth t8f sprocket that is 7.5" diameter and I think this would fit and not be too large to affect ground clearance but when using https://electricscooterparts.com/motorwheelgearratio.html and using the below specs;
- Amazon 2000w 48v brushless motor kit - 4300rpm AND 11 teeth that comes with it
- rear tire size of 18"x8.5"x8"
- And above mentioned 74 tooth rear sprocket

It says top speed is 34mph and gear ratio is 6.73
This seems way too fast and high geared. Not sure what the sweet spot is but from what I can tell it should be closer to 3:1. Our 4 acres has a couple pretty good hills and I would rather have a top speed half that and ability to go up and down hills. I and my wifey want to ride the thing too so 200# for me although I would be limited usage as I love the Kawi 300.

Am I chasing a unicorn with one of these cheapo amazon brushless kits that get mixed reviews? Please don’t flame me but I have been looking at cheap kits on amazon. I will say I am on a budget but would rather buy something one time and not learn the hard way smoking parts and breaking stuff. I like the idea of a kit but also have no problem piecing together. I can weld, read instructions and am very familiar dc wiring.

Any suggestions to point me in the right direction would be appreciated!
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if you don't mind lowering the top speed and power, find a large diameter chainring for bicycle chain, and mate it to the side of the sprocket on the rear axle.

Once that's done, everything else is easy.

Or, consider a QS 138/70H, they might have a stock sprocket that matches the quad sprocket.

You'd be surprised how easy it is to sell a running gasoline engine for these. Plenty of people have run these until the engine dies.
 
I build mine with the 2000w 45A Kunray kit powered by 56V EGO tool packs. Original config was 11:60 sprocket set up that topped out at 38kph. Due to the solid rear axle and current limits on the battery (~25A) it was under powered for hills and corners (solid rear axle). After adding a jack shaft I can now navigate the small hills and corners on the trails we walk/ride for my use-case. If you are looking for “fun” as opposed to the “mobility application” of my build I suggest you design to maximize torque which probably requires a better motor and more current from the battery than mine along with the largest rear sprocket you can fit.
 
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