Denzel 72v 4-spd Gearbox Build 125cc Dual Sport

[skeetab5780]

This is basically just a really cheap build so I can test out the new Denzel 4 speed gearbox drive. I found many very expensive options for frames with the E22 Honda mount, some street legal/some not. And none of them seemed well suited for my needs so I decided to buy a very cheap taotao DB17 dirt bike frame and adapt my own used bike parts to get the thing rolling just so I can get a sense of how this new drive will be on the road.




If perhaps I really like the Denzel drive I may possibly get a dual sport motorcycle and weld some mounts up for it after ripping the gas engine out to make a street commuter. But this will cost a pretty penny so I want to cover my bases before I get in too deep!

I already have a ton of 18650 batteries so getting the 72v to feed it is taken care of


I will need to confirm that the motor will run on a sine wave controller which I think it will being related the the D4500 but im not 100% sure. I would like to use the KLS series from Kelly I already own it and it will be easy for auto detection of motor halls

If not I have a KBS series I can also use
Obviously these controllers are more power than the drive states it needs, but id rather more than less and dial it down by programming


Thanks to efMX Trials Electric Freeride for all the help in selecting parts to get me started
and thanks Teslanv for the dropouts that will likely get welded to my swingarm in about a week

Here are pictures of me unboxing the Denzel drive, it came in about a week which is fast! Alex always sends me things in a prompt fashion



Chain sprocket cover

The outside if the box looked pretty good, but the inside was roughed up a bit, motor drive is so freaking heavy that it destroyed the internal packaging


I don't have a scale but this thing has to weight 35-40 pounds

The brushless motor placement is so staggered to the left off the drive unit, they had to make a custom shifter

I don't think it will be in the way, its not like I will have to pedal

Drive has a few warning labels make sure you fill with oil!


Custom shifter, im sure I will have to modify it more later!

 

[skeetab5780]

After just recently dropping a magnet in my 72v Voloci motor, I decided to scrap that project and use the bike parts for this custom build! Its going to be challenging and take a month or so, but I will get it rolling!

Parts being salvaged from the Voloci
Front downhill fork
Front wheel
Rear wheel
Possibly the upper seat stay and seat
Complete brake system
72v battery

I had some trouble with the headset sourcing since this bike had a 46.5mm ID headtube and the closest headset I could find for it was 44mm similar to the Kuberg build. So I had to make some 1mm shims to fit the cups in place

I am still waiting on the headset so the forks aren't in place yet

This frame looks small and I did tons of research on pit bike frames before I bought this and I still decided to go this route because of the price. this frame was only $59.99 free shipping from factory

The motor bolts right in and makes it easier to get things rolling, the top motor mounts are not installed obviously

 

[skeetab5780]

I was thinking about attempting to make a swingarm with parts kicking around, I threw some ideas around to get my mind working...Not much happening just yet

This bike will be a bit small by the looks of it, but I may be able to raise the upper seat stay and make it work. I wont really know until I get the wheels on the ground and bolted in, then I can figure out where the foot pegs need to be

I threw the Voloci swingarm on the bike out of curiosity, it is only about 2cm too skinny from bolting right in, but since its aluminum and very complex suspension linkage its not worth trying to adapt it to the frame

Then I started looking in my ATV scrap bin and found some 400ex shocks that have some bushing on them that could be used to make a swing




Then I just found some rectangular stock and sized it up against the bike also to get ideas, what I was worried about is the chain line mostly, that's why I don't want to get involved with a complex swingarm



also dropouts from Teslanv just came in the mail! thx again

 

[SlowCo]

:thumb:
I'm going to follow your build. Good luck and have fun!

 

[John in CR]

Where can we find info (specs and pricing) regarding the motor and gearbox combo? It could be an interesting option for down here due to a lot of mountainous terrain away from the metropolitan area.

 

[Grantmac]

Why not buy a swingarm? They are plentiful and cheap.

 

[skeetab5780]

Why not buy a swingarm? They are plentiful and cheap.

Already bought the swingarm and the stock shock, but since im on the tall size i will likely lengthen it with the dropout plates somehow since this is a kids bike setup with a 14” rear wheel and im running 17”

 

[skeetab5780]

Where can we find info (specs and pricing) regarding the motor and gearbox combo? It could be an interesting option for down here due to a lot of mountainous terrain away from the metropolitan area.

Here is a link to the Eastgem website for more information on the drive
http://www.eastgem.net/gearbox-110.html

They dont really give much information at all
They dont specify weight
They dont give any motor details
They dont tell you what oil to use(like it matters)
They dont even tell you the sprocket size (428)
Price is $599 shipped to anywhere which is reasonable considering E22 mount engines are roughly $300

Alex who runs the site is quick to reply to my emails. If you need his contact info PM me

 

[efMX Trials Electric Freeride]

Where can we find info (specs and pricing) regarding the motor and gearbox combo? It could be an interesting option for down here due to a lot of mountainous terrain away from the metropolitan area.

Here is a link to the Eastgem website for more information on the drive
http://www.eastgem.net/gearbox-110.html

They dont really give much information at all
They dont specify weight
They dont give any motor details
They dont tell you what oil to use(like it matters)
They dont even tell you the sprocket size (428)
Price is $599 shipped to anywhere which is reasonable considering E22 mount engines are roughly $300

Alex who runs the site is quick to reply to my emails. If you need his contact info PM me

Cool build

e22 crankcase transmission uses 4 stroke motorcycle oil.. might be a good idea to run break in oil before the first oil change.. check and change your crankcase oil regularly since these engines don't have an oil filter.. get a magnetic drain plug too..

example :
https://tboltusa.com/store/maxima-maxum-premium-break-in-cycle-oil-10w30-1l-p-8374.html

https://tboltusa.com/store/maxima-maxum-premium-cycle-oil-p-1367.html

 

[skeetab5780]

Thanks for the tip and links! The magnetic drain plug is a good idea I would have overlooked otherwise.

I would have guessed 10w-30 or 10w-40 just from my old ATV riding days, but since all the trails have been destroyed and lost to new housing developments its hard to sneak around on gas bikes anymore without getting in trouble

 

[skeetab5780]

I haven't gotten around to testing the drive but I should at the least get a no load test in real soon. There is some sort of gear shifter indicator wiring loam coming out of the drive and if I was to guess it tell you which gear you are in? But the wiring was squished by the weight of the drive in shipping. I don't think this will be an issue since I can just cut them shorter. I don't think you actually need to use these, its only if you want to wire a cluster for N-1-2-3-4



You got to love the spelling, we get it still!


This is the first time I actually looked at the bottom of the drive. Seems to have the mounting spots for a skid plate too maybe?

 

[Grantmac]

Is it as wide as it looks? That's a very reasonable price for what you're getting. Should make a great little power source for a variety of small EVs.
I wonder if the gearbox could hold up to a d7500?

 

[skeetab5780]

Is it as wide as it looks? That's a very reasonable price for what you're getting. Should make a great little power source for a variety of small EVs.
I wonder if the gearbox could hold up to a d7500?

13.5" width

 

[efMX Trials Electric Freeride]

I haven't gotten around to testing the drive but I should at the least get a no load test in real soon. There is some sort of gear shifter indicator wiring loam coming out of the drive and if I was to guess it tell you which gear you are in? But the wiring was squished by the weight of the drive in shipping. I don't think this will be an issue since I can just cut them shorter. I don't think you actually need to use these, its only if you want to wire a cluster for N-1-2-3-4

You got to love the spelling, we get it still!

This is the first time I actually looked at the bottom of the drive. Seems to have the mounting spots for a skid plate too maybe?

yes the bolt holes under the engine are for mounting skid plate and or peg bar..

gear indicator wires usually not needed / used ..

 

[John in CR]

Here is a link to the Eastgem website for more information on the drive
http://www.eastgem.net/gearbox-110.html

They dont really give much information at all

Thanks, that's plenty of info for me once you give us weight and some measurements. The `1200W motor rating at 72V tell me that it's essentially the same motor I've seen on some tiny electric cars, and not really comparable to how people on the forum talk about power. Add in those rpm and max torque numbers and that's lots of useful into, including even what they use as max current in the testing, since once you have rpm/volt you also have the torque constant (torque/amp).

John

 

[John in CR]

I look forward to the no-load current number. If there's an easy way to pull the drive gear to get a no-load current number of motor only along with including the gearbox, that would be an awesome comparison that answers questions I've had for many years.

Since it apparently has a neutral, no-load current in neutral may be motor only, or at least very close to it, so no need to open anything. Comparing no-load in neutral vs in gear will be interesting, as will another no-load measurement in gear after the gearbox has some run in time, especially with that sticker they put about changing the gear oil so frequently early in its life.

 

[skeetab5780]

I can confirm the motor does not run with Sine wave controllers.... sigh constant bucking and hall errors

KLS still collecting dust

draws 6.5amps at 10s full throttle which is pretty high id imagine the motors no load current should be less than half of that without the gearbox

The first minute of this video is the Hall identification process, sorry its so boring
https://www.youtube.com/watch?v=7f315I263uE

 

[skeetab5780]

Swingarm, bushings, headset and rear shock came in the mail

New total for the build is at $300 for bike parts and $599 for the drive

so I was able to make the thing start looking like a bike and get ready to weld the dropout plates on, again I think these plates are going to work out perfectly! Lets hope it goes EZ


The throat of the headset cups were a tad smaller in diameter than I would have preferred, hopefully the headset holds up with the shims in place

I just used bolts from my ATV pile of junk to save money for now

You can see they are a tad long but its not a big deal to me

Put the wheel in place just to get an idea of height


Wheel is a tad small but once dropouts are in place I think it will work well


I will have to cut the back half round off the swingarm and then weld these in place

 

[skeetab5780]

Rear wheel is still not attached, but the seat sub frame came in and the Voloci seat looks like it will fit right in place with very simple mounting! Saving more money reusing stuff

Its starting to look like a bike!

 

[John in CR]

draws 6.5amps at 10s full throttle which is pretty high id imagine the motors no load current should be less than half of that without the gearbox

6.5A at 40ish volts...In gear or in neutral?

 

[skeetab5780]

draws 6.5amps at 10s full throttle which is pretty high id imagine the motors no load current should be less than half of that without the gearbox

6.5A at 40ish volts...In gear or in neutral?

In gear with 36vdc tested with meter. I will hopefully get it hooked up to the KBS soon, but I will likely wait until the drive is mounted to the bike so maybe next week right after welding the dropouts

 

[John in CR]

234W to turn the motor and new gearbox not run in yet at half rpm doesn't seem bad to me at all. It will be interesting to see how the no-load changes as the gearobx gets run in and add the wheel and chain. Personally I'd give it 15-30min of run in each geat at that 36V before full assembly and change the oil including an extra rinse with clean oil and a minute or two in each gear, so once I got it on and ready to go I wouldn't have to baby it. Plus no-load info before and after would be great info. I've wondered for years what the efficiency loss of gearboxes and strong chain really is, especially since I'm such a lover of hubbies when they're up to the application. Except for the windage of the wheel those losses should be pretty linear, so it won't matter doing it at 36V or full voltage and the instructions say break it in at modest speed anyway.

 

[skeetab5780]

So I think I may be able to use the swingarm without welding the dropouts in place. I think I'm going to just get a longer axle and some spacers...the wheel fits great in the swingarm and the dropout plates will make sprocket clearances harder to line up center to the drive

Figures I already ordered a $20 axle that is too short now, but I think it will be easier in the long run this way


Used a few spacer bushings from a 300ex suspension linkage


Now I need a smaller sprocket that will adapt to the drive, using the same pitch but skinnier rear sprocket I think its #40

sacrificed one Voloci OEM sprocket to make a sprocket spacer to play the new sprocket off the hub more...hopefully this will be enough, if not a new hub may be down the road...


finish product, good enough for me

 

[skeetab5780]

Looks like the chain line is still a bit off, will need to play the rear sprocket out a little bit more

FYI this drive weighs more than the darn bike! Mounting it is fun...



Sprocket still set in a bit too close to the wheel

Drive is bolted in temporarily since bolts are not perfect sized

I wanted to run a small rear sprocket so I could get as much top speed as possible since this has gears for hills, but this sprocket seems a bit small, not sure yet

Need to play the rear sprocket out atleast 1/2"

 

[larsb]

This'll be interesting! I've always thought that gearboxes for electric motors are not needed since you could get a bigger motor for the same weight and money of the gearbox+motor assembly.

I hope it turns out well for you!