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

[skeetab5780]

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!

there are already ton of videos of the Denzel drive in action on Youtube. Most people have thought the same for years doesn't mean there is not someone thinking different. it also doesn't mean it will be viable or more efficient...but the drive does propel a full size moto down the streets at 40mph

The weight is definitely scary, these voloci wheels are bullet proof and i'm still not sure they are wide enough for this thing. But then again this is just a cheap test bike. If these drives are fun at all I will mount it in a dual sport or buy another...

 

[larsb]

For a budget build i think motor and gearbox is a viable option as it can give you both speed and torque without a massive battery and battery cost.

We'll see what you think about it in the end

 

[skeetab5780]

I rode this bike today very briefly and i have to say this drive is seeming awesome so far, super smooth and quiet and powerful, first gear is very slow and made for hills even on 72v, still dont even have oil in it, it was rainy so didnt do too much

Fourth is fun and you can take off in it on a flat without much issue. Im using a KBS 50a peak controller which is plenty of power for it. No top speed gps yet maybe tomorrow


I did change the front counter sprocket to a 14t 420 just because thats the size chain in which i owned a masterlink, this hurts my top speed but saves me weight with a bulky 428 chain. I can get a larger sprocet if top speed is too low

The gears are a bit odd since you can cycle them up or down, or keep going in one direction and they will keep cycling over and over

 

[efMX Trials Electric Freeride]

I rode this bike today very briefly and i have to say this drive is seeming awesome so far, super smooth and quiet and powerful, first gear is very slow and made for hills even on 72v, still dont even have oil in it, it was rainy so didnt do too much

Fourth is fun and you can take off in it on a flat without much issue. Im using a KBS 50a peak controller which is plenty of power for it. No top speed gps yet maybe tomorrow


I did change the front counter sprocket to a 14t 420 just because thats the size chain in which i owned a masterlink, this hurts my top speed but saves me weight with a bulky 428 chain. I can get a larger sprocet if top speed is too low

The gears are a bit odd since you can cycle them up or down, or keep going in one direction and they will keep cycling over and over

please don't run it without oil..

 

[skeetab5780]

you guys act like the little brushless motor is going to outlast the gearbox! I'm sure ill break one of the two

the test ride was in a flat 50' warehouse back and forth, hoping to get some oil in it today though

I really dislike how the gears are never ending and cycle in one direction, I would feel much more at home if it had N on the bottom and 1,2,3,4 up above it like a more normal bike

 

[skeetab5780]

Went to the hardware store so I could get the bike up and running, needed some m6 rod couplers and long m5 stainless bolts to extend the sprocket off the rear hub ISO. Seems pretty solid so im happy with the $20 investment. Also got new m8 motor mount bolts and installed the rear axle which I didn't take a picture of, rear axle is a m10x 230mm hardended steel with 4 bushing from a 300ex, two of them needed to be cut down with a dremmel

I somehow paid for 6x bolts at the store but when I went to put them on I only had 5x... got to love when that happens!

Ive had this sprocket for about 6 years with no need for it, I had to drill the ISO 6 bolt pattern out but it worked pretty decent


Chainline is fixed!


This chain seemed like overkill so I went down a size since I had the hardware for 420 and I was missing a masterlink for the 428

I lost a little top speed with this counter sprocket change but if its that bad I will increase it a few teeth later


Added this random rubber thing I had kicking around with a m6 bolt to hold it in place, sort of acts like a chain guide at the moment


Im still waiting for my swingarm linkage bolt, im using a random 3/8" rod at the moment and its not so strong

You can barely see the new rear axle here

Wired the controller in place all messy can fix later

Zip tied 20s 6p battery to the frame for testing

Immediately noticed I had to put a chain tensioner in place to keep the chain tight..

seems nice and solid now just need swingarm bolt then we will be good

 

[skeetab5780]

Actually was able to use a extra m10x 220mm axle for the swingarm bolt and it was almost perfect size, Had to remove the rear shock and also tighten the chain again afterwards, but it should be bullet proof now


Threw one extra washer on the inside of the swingarm to tighten it to the frame, there is zero play now


drive pic

 

[skeetab5780]

Threw some Voloci footpegs on the bike just so I could actually ride it more than a few feet, they are too close to the frame for a long term solution but they look cool for now, they also don't fold up properly but who cares for now

Just had to drill two small holes on each side

 

[skeetab5780]

Got some $2 oil at the store to give this a few miles before a oil change...

I have to throw an amp meter inline with the KBS controller since for some reason I am getting a error code sometimes causing me to cycle the power to resume riding. Hopefully not running a false combo

 

[skeetab5780]

Ordered a 16t front sprocket to increase the top speed since gear one is like super slow rock crawler with the 14t and 4th was probably 35mph top speed, this 2 tooth change will get me to my happy place I think

the gear shifter is not in a very good spot because of the motor and it will need to be highly modified to find something that is doable on the fly...right now the left peg needs to be way off the bike and the shifter is still too long for my size 13 shoe to reach

it is fun to shift a bike again! very fun

 

[RLT]

Thanks for the regular updates. This is a very interesting project to me.

 

[John in CR]

Instead of spacers between the hub and sprocket, I think it would be easier to do it with washers on the axle. Then just dish the wheel some at the end to center the tire after you get proper sprocket alignment. It looks like dishing will be needed anyway.

Something I've been wondering about is how will you know when it's time to downshift? I'm assuming you're not going to run at very low power, where the motor bogging down becomes obvious on a hill that's too steep for the gearing. Even at modest power motors and controllers gladly kill themselves to provide torque without making a peep. I'd think that the optimum way to ride under heavy loads, whether it's steep climbs or hauling heavy weight is to keep it in the lowest gear possible for the speed you want. Without the audible clues given by a gasser it will be interesting to find out what is optimum.

 

[neptronix]

Can't wait to see it rolling. Very cool

 

[skeetab5780]

I was doing some wheelie starts in first gear in the parking lot and you know how I told you I bought 6 bolts but only had 5 when I got back from the store, the last short bolt that I put on my sprocket in its place wasn't long enough and they all loosened up because of this and I slightly stripped out one of the holes in the hub. I put a extra long stainless bolt in again and re tightened them all down with a ratchet this time, hopefully they don't break. The sprocket is obviously under a ton of stress/torque since its mounted so far off the actual hub.

I don't know what I was thinking but it was fun. the akward shifter/foot pegs make it hard to go far

also I haven't had to worry about downshifting yet, since im still trying to find proper peg/shifter location to worry about upshifting first. still haven't gotten around to welding pegs on in the proper spots

yes climbing hills in the lowest gear will yield the best efficiency hands down, but this drive is quite weird since you do not actually need to shift it if you don't want to. You can just put it in any gear and take off just like a semi-auto matic quad or dirt bike. But taking off in 4th gear will drive the amps way up and possible burn out the motor over time, up a hill especially. But it pulls like a boss in 3rd gear with this Kelly 55a peak 26a continuous controller

 

[fechter]

Cool. That shifter does look really awkward. The shifter axle looks prone to getting bent too. I've seen some bikes that have the shifter arm going backward from the shaft. If your foot pegs are rearward enough, it might work with a shorter shifter arm. I've also seen bikes with a linkage to the shifter. With a linkage, you could put the shifter in a much better spot.

 

[skeetab5780]

so the 16t sprocket came in and I threw it on, it is now the same configuration that it comes from the factory just 420 chain not 428


I got a GPS top speed of only 30mph on flat ground in 4th gear...hmm seemed a bit faster than that. Will try again with batteries fully charged soon don't have a ton of time to dedicate

 

[Dui ni shuo de dui]

Very interesting build, this gearbox setup is sweet.

I just worry about the way you attached your sprocket, I don't think this will last. At some point the bolts will probably just snap.
If you can, you should probably try to machine a thick round plate with holes, instead of those spacers, that will spread the load more equally on all the bolts and should be much more resilient.

 

[skeetab5780]

Very interesting build, this gearbox setup is sweet.

I just worry about the way you attached your sprocket, I don't think this will last. At some point the bolts will probably just snap.
If you can, you should probably try to machine a thick round plate with holes, instead of those spacers, that will spread the load more equally on all the bolts and should be much more resilient.

I agree! thanks for your comment. this gearbox is a torque monster! But I need more top speed, I may need an even smaller rear somehow...

 

[efMX Trials Electric Freeride]

Very interesting build, this gearbox setup is sweet.

I just worry about the way you attached your sprocket, I don't think this will last. At some point the bolts will probably just snap.
If you can, you should probably try to machine a thick round plate with holes, instead of those spacers, that will spread the load more equally on all the bolts and should be much more resilient.

I agree! thanks for your comment. this gearbox is a torque monster! But I need more top speed, I may need an even smaller rear somehow...

17t 420 "counter shaft" engine sprocket for e22 pit bikes and mopeds is a very common size so probably can find one cheap on ebay etc for a bit more top speed..

 

[skeetab5780]

Very interesting build, this gearbox setup is sweet.

I just worry about the way you attached your sprocket, I don't think this will last. At some point the bolts will probably just snap.
If you can, you should probably try to machine a thick round plate with holes, instead of those spacers, that will spread the load more equally on all the bolts and should be much more resilient.

I agree! thanks for your comment. this gearbox is a torque monster! But I need more top speed, I may need an even smaller rear somehow...

17t 420 "counter shaft" engine sprocket for e22 pit bikes and mopeds is a very common size so probably can find one cheap on ebay etc for a bit more top speed..

Yes I ordered the 17t, I officially have every size countersprocket they offer...

 

[skeetab5780]

So lots of parts came in got the 17t sprocket had to order a new chain since I cut mine down too short for the 14t

and I ordered the foot peg mount for the bike for $22 also. Maybe this will get the footpegs out enough to shift comfortably?

running total is $400 now for all parts except the drive

 

[Overclocker]

very nice project! i need exactly that: low-range gears that could get me through super loose sand and up super steep terrain while keeping power draw low

btw i noticed your industrial chain. mine are doing well so far. i think these industrial chains have harder metallurgy than (cheap) moto chains

 

[skeetab5780]

very nice project! i need exactly that: low-range gears that could get me through super loose sand and up super steep terrain while keeping power draw low

btw i noticed your industrial chain. mine are doing well so far. i think these industrial chains have harder metallurgy than (cheap) moto chains

this thing certainly can climb in low gear, but keep in mind the drives added 30lbs... dirt bike not pedal bike

I put a 17t sprocket on to get even more top speed since im used to 40plus mph especially at 20s

machine chains are good but I don't put enough miles on them to give a review sadly...I just buy them because they are cheap cheap

 

[skeetab5780]

threw the 17t on with the new longer chain since I cut my old one down too small for the 14t...


I like it better with the wheel pulled back father anyway, but I think the front end needs to come up a little eventually, fork is maxed out so I need a larger wheel or new fork

Foot peg mount bolts directly to the motor and frame with m8 cap nuts and bolts

This footpeg looks good

This one does not...overall they are still not even close to being where id like them, this part was only $20 so it worth a shot and the foot pegs I bought for the kuberg and didn't need them since they were wrong, fit this nice
now, but I would also like them back and lower another inch or so

 

[Dui ni shuo de dui]

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.