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

[SlowCo]

This motor with gearbox is mostly suited for ATV/quad/cargo 3 or 4 wheelers IMO. Not for narrow 2 wheelers/bikes.
The fact that you only need a simpler/cheaper battery pack to be able to haul heavy cargo and/or tackle steep hills by selecting a lower gear is the selling point of this combination.

 

[skeetab5780]

I really wonder why they put the motor on the side like this. It takes a lot of space, it protrudes a lot. It's not really well suited for a 2 wheeler.
Would have been much better if the motor was on top or slightly in front of the gearbox unit.

They probably didn't want to bother with modifying the original engine casing, but that's a bit of a mistake IMO.

I agree this thing is so akward to shift and its never going to be nimble enough for me...especially on the small DB17 frame. If I put it on a 250cc street legal endure maybe...But then its too slow 38mph with 20s is silly

Im sure it was the cheapest way to get this thing to market, and its a flaw

 

[skeetab5780]

This motor with gearbox is mostly suited for ATV/quad/cargo 3 or 4 wheelers IMO. Not for narrow 2 wheelers/bikes.
The fact that you only need a simpler/cheaper battery pack to be able to haul heavy cargo and/or tackle steep hills by selecting a lower gear is the selling point of this combination.

I'm more curious why they didn't use a 48v motor with a different KV to offset the lower voltage. Making it 72v rated and it being this slow is a brain teaser to me...atleast if it was wound for 48v it would be fast enough for bikes running 20s

im running a huge front counter sprocket and a tiny rear sprocket with a small 17" moto rear wheel and it barely does 40mph on 20s 18650. My LRHDD kuberg is faster direct driven on 18s

I guess this is one more hint that this may be more suited to ATV/UTV since it is certainly a torque monster, I could put it in first gear and climb a hiking trail no problem, you will fall off the bike before it gives up

 

[stan.distortion]

Just a thought on the gearchange, is the motor braking when the throttle is of or spinning freely?

EDIT: Nice unit too! Looks like it's based on a Honda 50 gearbox and those things did more for motoring than the model T (and maybe even the VW beetle).

 

[polynoth]

I am thinking of taking a gamble, and ordering this and seeing if I can make it fit into my 1979 motobecane v50.... if not, I'll order a motoped frame kit, as I know that will fit.

 

[efMX Trials Electric Freeride]

did you see the new CB CG gearbox engine ??
https://endless-sphere.com/forums/viewtopic.php?f=31&t=91761&p=1478105&hi#p1476034

http://www.eastgem.net/gearbox-200.html

 

[skeetab5780]

Pics not working?

 

[amberwolf]

fwiw, it looks like your pics are hosted on google somewhere, rather than attached to your posts here on es (and thus saved with the post). i can't view them even if i copy the image url and paste them into the url bar of the browser. so they're either missing from those specific links, or you don't have permissions set to allow others to view them.

it's also possible that google changed something (even just one character) in those ********extremely******** long urls, whcih means no link using the previous url will work anymore.

or they may have disabled external site access to pics on their servers, like photobucket did.

so while your pics may still be out there on google's servers, you'd have to find them on whatever webpage you used to upload them, and then relink them in each of your posts so that everyone can see them again.

instead, i would recommend that you always attach your pics direclty to your posts, so that anyone that can see the post can see the pics.

 

[skeetab5780]

I took this drive out of the db17 and im in the process of mounting it into a 2002 Zongshen gy125 enduro dirt bike frame i picked up reasonably cheap not running. Already tore out the gas stuff and should have the denzel gearbox fitted up in the new frame soon

The db17 was just too tiny to work with this heavy ass gearbox, especially with the small voloci moped wheels. I think i will use this rolling chasis for a different mid drive project. A dirt bike for the kids

The 125cc Zongshen frame is quite a bit larger similar to the Apollo 250 size wise, should make for a reaaly nice silent trail cruiser to play around on. Likely throw a quick 72v 20s pack in it somewhere above the drive

Total build cost
$200 - 125cc Dual Sport used
$400 - Denzel 4-spd drive
$129 - Kelly Controller KBS72121X
$289 - China battery packs 20s6p 18650
$20 - #40 chain From Apollo 250 build
Just over a grand

 

[skeetab5780]

Here are a few pics of the Denzel drive swap, it took a few days to figure out the easiest way to make the four brackets to mount this heavy drive without having to use too many tools...(hack saw, file, bench grinder, dremmel, drill)

My son Vinny made one of the top brackets and i made the other, made the project go a little faster, we adapted them to the original engine mount bolt reusing the bushing and one more from a Voloci as well

The bottom brackets are a gauge or two thicker steel and they were hard to file the engine groove into them, i may tack weld these in place before proper testing due to the odd angle/power distribution

A shot of the bike from afar, before controller mounting

A shot from the right side of the drive, we tried to get the Denzel writing as level as possible when the bike is upright

We are planning to use the front engine mount plate and weld a front drive support to the four original foot peg mounts on the bottom of the Denzel drive for extra support and to complete the frame loop

Wired in the controller and throttle, to find out how much room i have for batteries

Here you can see the old 125cc gas engine we ripped out in the background, the drive certainly weighs less than the old gas motor but when you add the battery weight it will likely be a wash


This bike will be an ugly crawler soon enough! Still need to work on a better shifter setup, but now that the drive is on a full size motorcycle the pegs are a bit futher apart making it feel more normal

 

[skeetab5780]

I havent been taking too many pictures of this build but my son Vinny and I have been working on this bike all weekend. The drive/frame mount is finally complete. I did not take too many pictures of my really funny welding skills since i'm still so bad at i just focused on making it safe-ish and getting it done.

Cut the bottom drive mount out of a piece of plate steel


Then made a few other pieces attach to the frame as easy as i could, it likely not the strongest but its plenty strong enough for the 3kw that the drive supposedly puts out

One of the reasons i kept the mount to the frame so flat was so i could still put the stock bash plate back on, once i do this itll make it look more normal lol

 

[skeetab5780]

Got the bike out for a test ride!!! Stay tunes for the fun

So i got a shifter to work by cutting it in half, but its not ideal since you can only kick it down and it starts in fourth gear...Luckily its a semi auto so no big deal for now




Welded a front battery support to the frame

Put the #40 chain on

Then started on the back of the battery mount



They fall right into place


Then i cut a clearance hole into the skid plate so i could fit it back into place(cut the hole about 1/2" too wide since i guessed...Doh) still works fine obviously



Wired it up real quick to test the wheel spin, ready for testing now



Here you can see all my other bikes piling up!


I quickly noticed i had to open batteries and bypass the BMS on discharge since these are cheap china packs...they will get abused nicely(they actually aren't horrible for the $129 each)



Just added 12awg Cu str wire straight to the welded tabs, but kept the BMS for charging the batteries since its nice and small/neat

Taped then all back together with some Shuretape (knock off Gorilla tape) taped the series connection together since it will likely stay like that for a while

Photo shoot after successful test rides!

 

[skeetab5780]

Quick test ride video nice and slow no helmets yet...too excited to notice at the time
[youtube]FpvaMjS3UmA[/youtube]

 

[SlowCo]

Great result so far :thumb:
Was that the police siren in the background in the last seconds? Just before you were caught... :lol:

 

[skeetab5780]

Great result so far :thumb:
Was that the police siren in the background in the last seconds? Just before you were caught... :lol:

Haha funny i thought the same thing when i was editing the video! But no, silence is innocence around here

 

[fechter]

It's alive! Nice work. Seems to run OK. It will be interesting to see how it does at full speed.

 

[skeetab5780]

It's alive! Nice work. Seems to run OK. It will be interesting to see how it does at full speed.

Its using a Magura pot throttle and there is a slight dead spot in the front, i have no resistors in the circuit just selected pot throttle via Kelly programming. The motor jerks the chain a bit before engaging fully, may need to tighten the chain a bit more.. but when my 230lb butt gets on the bike its pretty tight

I may need to try another throttle just out of curiosity? The drive does not work with Sine wave Kelly Controllers it has the bucking signal issue so im using the old KBSX series

 

[SlowCo]

The motor jerks the chain a bit before engaging fully, may need to tighten the chain a bit more.. but when my 230lb butt gets on the bike its pretty tight

Maybe a spring loaded chain tensioner might help?

 

[skeetab5780]

I rode this thing around for over an hour yesterday and its pretty impressive. Climbed a really steep dirt hill with no run-up and barely made it because i was in 2nd when i thought i was in first gear...Tried it again in first does it slow but easily

Cranks over big logs like a gas bike in 2nd and first, first from a stand still i can wheelie onto 18" downed logs and climb the back tire over with a foot on top of the log

Gets up to 50kph in fourth gear on flat at full speed, at least that is what the old speedo says on the dash, the front wheel is very warped and needs to be replaced so that is an issue in fourth gear a bit. Also the front caliper is locking up, so i took the system apart to clean it and still have no front brakes as of right now since i cannot seem to bleed the air out of the system now even though i did it once before when they locked up...idk

i tend to ride tight trails in second and the rest of the time in 3rd gear but because the shifter only works in one direction its a pain to cycle to the gear you need since its always downshifting starting at 4,3,2,1,N, repeat...

I may try to weld another shifter on

Towards the end of the ride i pushed the batteries a little too far already(they are brand new)...trying to climb the big hill again doubling(two riders) with over 300lb rider weight and it struggled as the packs dropped a little too low for my liking. Then i decided to put it away and throw it on charge with the Satiator(the best charger ever)

This bike needs a $1000 battery pack and i spend $289 on this China battery pack...you get what you pay for. But i am happy with this battery for the price and it was able to get the test results in and it performs decent IMO

 

[macribs]

Cool skeetab, nice to see this coming together. Is that Denzel gearbox using the D4500 motor from Denzel? Seems that is a 1500 kw motor? I wonder how the gearbox would hold up to say a powerfull 10-15 + kw RC motor? It would still be a relatively decent weight, but should put a little extra smile on your face when need be. Then again, I don't know how the output power in that d4500 motor is. Is it like conservative numbers like we see from ie QS or are the power numbers bit "inflated" or at best only usable for a few seconds burst of peak power, like we know from RC motors?

I am trying to take this gearbox/electric motor combo in to be aware how I feel about it. The gearbox does eat up some valuable real estate. And it also add a bit of weight. I think a mid motor that can take up this much room of space and weight, should yield a wide variety of candidates to choose from, and likely the power output for such motor should easily be close to 20 kw or more. Is there really a need for a gearbox? I mean most threads about gearboxes get at least one response saying to rather put the money, weight and real estate a gearbox takes up into yet a better and bigger motor and net result gets to overcome the gearbox combo.

Yet, there is something a little cool about a gearbox. Like the ability to never stall. Keep climbing almost vertical walls.

I can't really make up my mind on this one. Gearbox or no gearbox. That's the question. And if a gearbox is chosen, would it make sense to pair it with an obnoxiously powerful motor? If a 1500 w motor becomes strong and usable with such a gearbox, how much fun would a motor with 10 + times the power make? Would 4th gear be the default gear and you would never dip into the lower gears or would even the lower gears make sense? Forgive me for asking, but this gearbox. Does it got a clutch? Wonder what crazyness can be done with a clutch, gearbox and a powerful motor? Moto x style clutch slipping to keep rear wheel speed high when need be? Or trail style clutch and throttle blipp?

 

[efMX Trials Electric Freeride]

the twinsluck CB/CG gearbox is clutched 4spd .. but denzel eastgem e22 pitbike gearbox is semi-auto trans, has shift lever but no clutch lever.. advantage of gearbox for off-road is for steep terrain, etc..

example: with single gear you need large rear sprocket for steep climbs.. but then have reduction in top speed for flat or dh.. gearbox solves this with selectable wider gear range .. at the expense of some efficiency losses, etc..

 

[skeetab5780]

Keep in mind this pig of a steel bike weighs over 200lb without a rider and we are another 300lbs doubling

Here is a sloppy video we made last night, i noticed my Kelly controller is blinking an error code while editing the video ill have to look into this
[youtube]_-9Bx-rhqxA[/youtube]

 

[skeetab5780]

Cool skeetab, nice to see this coming together. Is that Denzel gearbox using the D4500 motor from Denzel? Seems that is a 1500 kw motor? I wonder how the gearbox would hold up to say a powerfull 10-15 + kw RC motor? It would still be a relatively decent weight, but should put a little extra smile on your face when need be. Then again, I don't know how the output power in that d4500 motor is. Is it like conservative numbers like we see from ie QS or are the power numbers bit "inflated" or at best only usable for a few seconds burst of peak power, like we know from RC motors?

I am trying to take this gearbox/electric motor combo in to be aware how I feel about it. The gearbox does eat up some valuable real estate. And it also add a bit of weight. I think a mid motor that can take up this much room of space and weight, should yield a wide variety of candidates to choose from, and likely the power output for such motor should easily be close to 20 kw or more. Is there really a need for a gearbox? I mean most threads about gearboxes get at least one response saying to rather put the money, weight and real estate a gearbox takes up into yet a better and bigger motor and net result gets to overcome the gearbox combo.

Yet, there is something a little cool about a gearbox. Like the ability to never stall. Keep climbing almost vertical walls.

I can't really make up my mind on this one. Gearbox or no gearbox. That's the question. And if a gearbox is chosen, would it make sense to pair it with an obnoxiously powerful motor? If a 1500 w motor becomes strong and usable with such a gearbox, how much fun would a motor with 10 + times the power make? Would 4th gear be the default gear and you would never dip into the lower gears or would even the lower gears make sense? Forgive me for asking, but this gearbox. Does it got a clutch? Wonder what crazyness can be done with a clutch, gearbox and a powerful motor? Moto x style clutch slipping to keep rear wheel speed high when need be? Or trail style clutch and throttle blipp?

They say it is the d4500 motor but it doesnt look the same imo, i owned the d3000 and the d7500 but not the 4500, i just wish the motor had a higher KV per V so you could run it on 72v with a higher top speed

I think it has plenty of torque for the power it demands especially since im using a awful low C rating 20s6p pack and getting decent range and runtime(all guesstimates from years of battery abuse) this Controller is 26a cont

The gearbox is a heavy beast, but i absolutely love it when its installed in a dirt bike (not the small DB17 with voloci wheels,but a full size moto with real moto wheels) i have a feeling if you try to tow 500lb bike and rider weight with a direct driven BLDC motor you would have to gear it just as slow as this top speed which is around 30-35mph and it will likely require much more power to achieve similar stats and also produce more heat/losses while climbing a hill at low speed compared to the drive in 1st or 2nd IMO...Don't get me wrong I can jump on the Kuberg Freerider and crush this thing on a single track race or a timed trail ride, they are two completely different animals

Kuberg is a weight weenie LMX thats fast and agile
Denzel Zongshen dual sport dirt bike is a Tank to trail cruise and tow people around and rip mud and hills reliably

Eastgem now offers the 200cc version which has a clutch(they did not offer this when i purchased) I absolutely would have gotten the newer clutched version. it is a tad out of price range since i own 12 bikes already... but i still want it!!

this drive is 4-spd semi auto with a foot shifter. Just take it from me don't try to be a weight weenie with this drive, if you buy it mount it in a full size moto frame for fun. I have been noticing that when you hold the throttle wide open and the speed exceeds the drives powered RPM it sort of bucks or hits a neutral zone until it picks back up again. Like coasting downhill when throttle is maxed out and it tries to go faster than it can...I think if you put 15kw thru the drive you could easily overheat the motor leaving it in 4th gear doing a hill climb just like i did on my Apollo Dirt bike direct driven with the wrong gearing without a transmission.

 

[fechter]

It might work well if you could figure out a way to shift electronically. Something like a big solenoid or RC motor attached to the shifter and a button on the handlebars.

 

[stan.distortion]

It might work well if you could figure out a way to shift electronically. Something like a big solenoid or RC motor attached to the shifter and a button on the handlebars.

Add an arduino and you could even do full automatic gearchange going that route A linkage salvaged from a sportsbike (or something else with a rod linkage) would probably be the easiest option, graft a mounting for the lever somewhere close to the footrest. Those gearboxes are also often used by OEMs with an extended lever, it looks like it would need to come out another 3 inches or so to clear the motor and that looks like an awful lot of unsupported length but manufacturers don't seem to have any issues with it.