Breaking all the rules - cyclone dirt bike build

Kona Stinky frame
Cyclone 3000w motor
72v 50 amp 20ah battery
72v 50a controller
Full motocross body kit and seat

7 speed freewheel but using bigger gears only, you reach top speed in 4th gear anyway.

I'm amazed at how cheapie 7 speed chain has been holding up

This thing ripped.

As long as your deraileur is adjusted correctly and your primary chain is always tensioned, regular bicycle drive train can really take some abuse. I also run my pedal chain shorter than normal for best tension

Never had a pedal chain snap, only primary motor chains and those were only times when the chain tensioner became loose and no longer held the chain on tight. I have had chainring bolts explode on the other hand. Replace those with solid bolts and your good.


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Then one day something broke... out of all things, the brake mount side of the swing arm. Happened while tapping the brakes during a very slow wheelie with little force.


Broke off clean at the welds. Frame is from 01-03 so who knows...



They say if it ain't broke dont fix it... well its broke so let's fix it and also try to make it better... first rule broken dremeling off the other side of the swing arm...



We'll just chop this piece off of this steel swing arm, which attaches similarly to the seat stay the same way the kona does.. originally a circular tube and hammered down to ovalize and shim inside the kona..



Like a glove



Now let's start breaking more rules... drilling holes into the steel swing arm first..



Then into the aluminum swing arm



Slow and steady wins the race... trying not to heat up the swing arm too much or stress the area with too much pressure


They literally thread in



A bunch of nuts, bolts, washers, and spacers later...



Took the bike from a 44 inch to a 49 inch wheelbase



Now let's throw on a moto tire for that back wheel just because



And brace this back brake mount so no more brakes brake.. test mounting brace to be welded... seems legit



Weld and paint



Extending the swing arm by 5 inches and extra weight from moto rim/tire really ate away at that instant wheelie torque you normally get from a cyclone... so I shortened the swing arm down to 47 inches and shunt modded the controller to get some snap back... now this thing really rips.

I preloaded the rear shock a bunch of turns since extending the swing arm adds more travel and therefore more leverage on the shock... I wonder how much travel I gained by adding 3 inches of wheelbase?

I've ran this through some pretty knarley terrain and it holds up nice and stiff... rides over rough stuff like a cloud. Even taken some small jumps and hops here and there at speeds and no signs of stress. I honestly ride it like it never broke and it doesnt seem to be showing any signs of weakness or worrying flex even with the (so far) full power of this mid drive running through it

Oh yeah, I got tired of worrying about heat so I force air cooled the motor. Even though the cyclone has a thermal fuse which would disconnect the halls and make the motor error out in the event of it overheating, it was getting hotter by hand than I liked. So I made some holes and glued some tubes.



Now it gets warm at best no matter how hard I run it.. now its ready for more power... but maybe we should change those planetary gears out to steel first? Maybe lets see just how much the plastics hold up to first..

Thoughts? Much more to come...

I think I'm due for a fresh chainring :lol: this is the same one I've been using over a year now but it definitely was no where near this bad last time I had a look at i5



Only reason I even noticed is because the chain guard cracked off...I'm amazed this thing still runs as good as if the gears were fine.. not a single skip motor side even in this condition still popping wheelies and doing 40mph runs at high RPM...

Very cool bike. Seems like youre having lots of fun with this build.

Yeah, add a new chain and a new sprocket/chainring at the same time. You may not have had a bad chain-drop under power...yet. However, I'd recommend getting a chain-guide. They look similar to a small dérailleur cage, and once set, they don't move.

You would locate it on the top-run of the chain, right where it goes onto the front sprocket. Even with the chain bouncing around (*when you hit a bump/pot-hole/curb), the chain will reliably feed onto the top of the chainring.

TOLM said:

Very cool bike. Seems like youre having lots of fun with this build.

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Appreciate the comments! This is definitely my funniest ebike build to date. The power to weight ratio is just insane!

spinningmagnets said:

Yeah, add a new chain and a new sprocket/chainring at the same time. You may not have had a bad chain-drop under power...yet. However, I'd recommend getting a chain-guide. They look similar to a small dérailleur cage, and once set, they don't move.

You would locate it on the top-run of the chain, right where it goes onto the front sprocket. Even with the chain bouncing around (*when you hit a bump/pot-hole/curb), the chain will reliably feed onto the top of the chainring.

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Already got one of those in the form of a stationary front deraileur. It definitely helps out with the fact the stock chainring freewheel has slight wobble to it, no matter how much the chain wobbles and vibrates the front deraileur keeps it on that front chainring no matter what. I also have a chain guide on the bottom so when you back the bike up the chain doesnt want to fall off the front chainring, that was definitely annoying, and only because the 7 speed freewheel ment I never had a straight chain line. It's also made from an old deraileur haha







It's taken a few broken drive trains to finally get all those little tips and tricks working together to finally have something reliable enough to fly over any terrain and not have the drivetrain skip a beat. I've definitely learned the more expensive and hard way that it's best to change out both sprockets and chains at the same time. I'm just waiting for a new front chainring to come in before everything else. I also think since I'm overhauling my whole front freewheel it's time to ditch the stock one snd go with a nice expensive white brothers freewheel. Atleast that one wont send pedals flying at you at high rpms from failing..

And since its time for a chain-sprocket replacement I think it's the perfect time to upgrade and give this little guy a try and see how much power he can take ( funny because your the one who wrote a whole article about it!)



24T sprocket which is the main rear sprocket I stay on most of the time, so i will spend most of my time in the strongest gear since that's the 1:1. Hopefully first gear stands up to my wheelie addiction and 3rd gear is able to take the power of barrelling through wind and hills at speed. Definitely has some heft to it and I've read someone said these things take 4000w reliably as long as you dont switch gears under load. Its even handled switching gears under load with no problem so that should attest to its durability. That was never something remotely possible with my deraileur system so its nothing new to adjust to, I'd rather save that kind of extra abuse for more power I plan on staying around 50 amps peak battery and upping the rpms for more wattage and rpm based torque, rather than higher amperage based torque. 96v cyclone anyone?

Best part is these thick single speed cogs should have much more durability than the old 7 speed, even though I never had a problem with that bike chain or freewheel before. A extra strong single speed chain like a connex 1R8 would give me actual piece of mind knowing cheapie thin chain is still up for the task. No more chain movement or changing legnth to change gears is the main time your chain is at risk. Also thinking about running a connex IG8 as primary motor chain

I hope you have better luck with your SA hub than I have. I am about to take mine off and throw it in a dumpster. I give the hub maybe 5 minutes of your riding haha. Maybe the 3 speeds are stronger?

Since you don't have pedals I'd ditch the planetary gearbox then run more reduction to the rear wheel via a wide ratio cassette with the cogs moved around to only offer 2-3 gears with a very straight chainline.

The actual power may not be what's damaging the IGH; but rather the shock load of suddne torque application. That tends to rip the gear teeth off at the roots.


They'll also fail from too high a torque input total, but that's often a shear pin meant to protect the rest of the IGH from destruction (especially in a way that would allow the wheel to lockup).

So the IGH you have might be fixable. (you could put it up on ebay as a "parts only" unit, for instance).

There will be no geared hub that survives that torque with your two stage reduction. If you want, you can switch up to a 4kw cyclone, remove the reduction and run it up to 100-120a. It will still need the cooling but won't instantly burn down.

The 4kw is 30% wider with a steel gearbox.
You could do this and use the connex all the way to the back.

https://endless-sphere.com/forums/viewtopic.php?f=28&t=69867&p=1490202#p1490193

Aquakitty said:

I hope you have better luck with your SA hub than I have. I am about to take mine off and throw it in a dumpster. I give the hub maybe 5 minutes of your riding haha. Maybe the 3 speeds are stronger?

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I'm relying on the 3 speeds supposedly being extra durable..

Grantmac said:

Since you don't have pedals I'd ditch the planetary gearbox then run more reduction to the rear wheel via a wide ratio cassette with the cogs moved around to only offer 2-3 gears with a very straight chainline.

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It does have pedals hence the front freewheeling crank, and this bike is so light combined with the freewheeling motor that you can actually pedal it a decent distance with no power in an emergency situation. Saved me a few times after the battery died on me. Although when first messing with freewheels I was looking for a good casette that would allow me to position the biggest cogs in the middle of the casette. Also was worried about a freehub that's up for that kind of power level so I stuck to freewheels since replacing a freewheel is a lot cheaper and easier than a free hub. could anyone recommend one along with a steel casette with that kind of customizability with cog positioning?

Tommm said:

There will be no geared hub that survives that torque with your two stage reduction. If you want, you can switch up to a 4kw cyclone, remove the reduction and run it up to 100-120a. It will still need the cooling but won't instantly burn down.

The 4kw is 30% wider with a steel gearbox.
You could do this and use the connex all the way to the back.

https://endless-sphere.com/forums/viewtopic.php?f=28&t=69867&p=1490202#p1490193

Click to expand...

So no one has faith in this 3 speed holding up to any abuse? I did see that build and it does look a lot more cleaner and rugged but looks like some custom machining involved in that sprocket and crank for the motor...
The last thing i want to do is lace this all up just to have it break down the first ride.
I know once your past 4-5kw direct drive is the way to go. But I'm trying to keep it just around/under that for efficiency and weight. On top of the fact that this thing probably wont be stable past 45mph because it's so light and it already almost reaches that at current power levels, I dont need much more power as it would be a complete overhaul of all the components.

Finally decided to lace up that hub, just had to drill the spoke holes for 10g spokes... anyone who is curious to see just how much abuse a 3 speed hub can take, stay tuned



I had to keep the derailleur as a chain tensioner, as the chain legnth shortens as the swing arm goes through its travel. When the suspension is unloaded there is quite a bit of slack and I dont think a regular chain tensioner would be able to take up all that slack reliably.

First ride was smooth, didnt even need to use flux weakening for high top speed since shifting is so smooth and easy. The only reason I relied on it so much before was because shifting did not feel 100% reliable. ill definitely have to change this grip shifter for a trigger shifter. and apparently these hubs operate off the same principle a hub motor does, using the axle as a stationary mount to transmit torque through while the outer hub shell is what spins. This also means I will have to somehow make something to deal with the torque the axle will be putting out at the drop outs since it will want to force them open... definitely no wheelies for now until that's complete

Awesome build!
Are you using the stock cyclone controller? If not, what controller are you using?
Based on your video the throttle response looks really good.

I'm working on making a trials bicycle/motorcycle hybrid right now, and have a cyclone on order. My biggest fear is the throttle response and predictability. What throttle are you using?

Leanier said:

Awesome build!
Are you using the stock cyclone controller? If not, what controller are you using?
Based on your video the throttle response looks really good.

I'm working on making a trials bicycle/motorcycle hybrid right now, and have a cyclone on order. My biggest fear is the throttle response and predictability. What throttle are you using?

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You need a bluetooth controller if you go for cyclone controller. Then do: fast start 8, slow start off, boost off, adjust accelerator curve on.

Dang,
That'll be a problem initially. The only controller they had in stock was the tiny sinewave controller, which doesn't appear to be bluetooth.
At least it will let me get up and running..

Any updates on this build? Or a link to your YT channel? The video links are dead.

I'm interested because I'm dreaming of the same type of build. A MX/Enduro dirtbike based on a downhill frame. So, I'm curious as to how its holding up.

THanks!