SMALL - Telemetry SMALL - Radio
Thread Tools
Old Mar 09, 2012, 08:11 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Build Log
Ezip-1000 Conversion

Hi
i have been working on a conversion project and thought i would post a few photos

here is a good photo of the scooter i am using for this conversion , it is a 36 volt , 1000 watt , rear earth magnet motor , and as you can see they have it attached to the rear swing arm , the other issue with this scooter is that it is gear driven

I got on some of the scooter forums and read that the general opinion is that E-zip blew it by having the bike gear driven , two big problems are that the ratios cannot be changed and if you try to get parts you find out the the motor , gear train , and rear wheel , are only sold as a complete unit

i also read that it cannot be converted to chain drive , this worried me as i intended to convert it , but couldn't see what the problem would be , assuming that a person had some tools

The other information i found out , was that the E-zip is actually made by Currie and sold under a half dozen trade names , E-zip , Mongoose , Schwinn , ect ect ect

i started watching Creigs list and found one listed locally , Once i got it to my shop it took me about an hour to strip it down to the parts i intended to use in the conversion , and toss the pile of parts i didn't need into the trash , the third photo shows pretty much all that i kept
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 09, 2012 at 10:37 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 09, 2012, 08:12 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
The first order of business was to see if the drive train could be converted to chain drive , I was happy to see that it could be , and that it would be pretty easy , assuming you have a hacksaw and a metal lathe

The rear axle is part of the gear drive unit , but luckily the drive gear on the axle was just a light press fit with a keyway , and i was able to press it back out of the gear easily

Another interesting thing , that makes the conversion to chain drive easy , is the rear wheel is on what is called a floating or live axle , the axle is held to the rear swing arm by two bearing cups , which allow the rear axle to spin with the rear hub . And the rear hub is a press fit and keyway to the axle , there are not any bearings in the rear hub , this allows the freewheel to attach to the axle

Once the gear drive unit was removed from the axle , there was about 1-1/2" of axle exposed on the right side of the hub , this provided a place to mount a steel flange and a section of thread to mount a freewheel unit for the chain drive

here is a photo of the piece i turned on the lathe , there is a steal flange and four bolts to hold the threaded alloy section to it , this will allow the freewheel to thread onto the axle in the space that had been used for the gearbox
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 09, 2012 at 10:40 AM.
Reply With Quote
Old Mar 09, 2012, 08:13 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
This would probably be a good time to mention that i am using the dimensions of a Venom GPV-1 scaled up to build this bike

another area that needed to be reworked is the front fork , RC bikes have an interesting setback , in the front end , most easily observed by seeing that the front triple clamps are reversed as compared to a full sized motorcycle

the best way i have heard this described , is that if you were to project an imaginary line through the stem , the front axle would be behind this line

the problem with the stock scooter fork i had to work with were two fold , first the fork was set forward , and second the axle was mounted to the front of the fork tubes , this first photo shows the stock fork i had to work with

i wanted to build triple clamps to handle the setback , and to do this i could see that if i used the stock downtubes i would have to extend them in order to have material for the triple clamps could clamp to . Also the axle being mounted to the front of the shock tubes meant that the triple clamps would have to be set back an additional 1-1/4"

I decided to scrap most of the front fork and save just the shock tubes , I didn't like the idea of the axle in front so i decided the best solution was to cut the shock tubes completely loose and flip them upside down , so that they were held in the triple clamps , and i could now center the axle in the down tubes , this second photo shows the shock tubes cut loose from each other and the new down tubes and axle tabs , before welding
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 09, 2012 at 10:45 AM.
Reply With Quote
Old Mar 09, 2012, 08:14 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Another idea of the RC bikes i have seen , that i wanted to incorporate into my build , was the use of a spring loaded stem

These next two photos show the rough build sketch i worked off of , and the finished stem , with this spring cartridge attached

The third photo shows the 1/2" alloy triple clamps , and the last photo is the complete front end with the spring loaded stem
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 09, 2012 at 09:39 AM.
Reply With Quote
Old Mar 09, 2012, 08:21 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
For the frame , i used some 1-1/2 X 1/2 thin walled rectangular steel tubing , It is basically two tubes running 6" apart from the stem straight back to the top rear shock mount , and then turning downward to the rear swing arm pivot

Once these main tubes were finished , i came back in with some 1/2" thin wall tubing for the lower tubes , you can also see in this second photo that the motor mount has been added
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 09, 2012 at 11:10 AM.
Reply With Quote
Old Mar 09, 2012, 08:22 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
here is a photo of the frame in good light , and a few showing the batteries mounted in the frame
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 10, 2012 at 07:01 AM.
Reply With Quote
Old Mar 09, 2012, 09:41 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
The motor for this bike is a 36 volt 1000 watt , with rear earth magnets , and the scooter came with a controller

the only rub with this setup is that scooter controllers do not use a PWM signal that is compatible with an RC receiver for the throttle , So you have to convert from the RC receiver to the scooters motor controller for the throttle channel

the first photo shows the scooters throttle grip opened up so you can see the hall effect integrated circuit , and the magnet used to signal a change in throttle position

the second photo shows the same two parts that have been removed from the throttle grip and setup on a standard RC servo

one problem i ran into , the hall effect device has to stay in proximity to the magnet at all times , when it is at the one end of the magnet it puts out a 0.8 volt signal , and as it moves towards the other end of the magnet , this signal smoothly increases to 4.6 volts , But if either end of the magnet passes the sensor completely , the signal jumps to 2.5 volts , and this would slam the motor to half speed

IN order to not overrun the magnet , i had to turn the travel in my TX down to about 50% which was fine , But then when i mixed throttle to brakes , i only had 50% travel to work with for the brakes

My work-a-round for this was to add a magnet , which let me increase the travel to about 80%

in the second photo the blue line drawn on the magnet shows the point where the motor will start to turn , the servo wheel swings CCW with breaking and CW with throttle

I know this servo controlled magnet looks pretty " Mickey Mouse " , but if you look into buying a RC motor ESC for a 36 volt 1000 watt motor you will see why i settled for this solution
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 10, 2012 at 07:04 AM.
Reply With Quote
Old Mar 09, 2012, 09:41 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
The punch list for finishing the bike is pretty much

build three servo mounts

finish mounting the radio gear

there will be a control panel mounted on top of the frame , between the stem and the battery , for the power switches

I have a pair of 140mm kick scooter wheels that i will mount on the side of the frame for fall over

and a few assorted tabs to mount the controller and brake cable ends

and that will just leave paint

I will get back on and post photos when it is finished
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 10, 2012 at 07:14 AM.
Reply With Quote
Old Mar 10, 2012, 07:56 AM
scaulfi is offline
Find More Posts by scaulfi
Big thrills w/o hospital bills
scaulfi's Avatar
Brisbane, Australia
Joined Sep 2003
3,761 Posts
Absolutely awesome!.. Nice build/conversion..

This is something Ive always wanted to build, I just need one of these scooters I guess. Looks pretty straight forward. Love the wheels, tyres and disc brakes.

The only issue I see with the bike is maybe the battery position making the bike top heavy..

Realy looking forward to seeing some video of it running, on a kart track maybe.
scaulfi is offline Find More Posts by scaulfi
Reply With Quote
Old Mar 10, 2012, 08:30 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Hi scaulfi

thanks , i can tell you , it has been a ton of fun working on it

I was worried about the battery placement also , and after thinking about it for a day , i realized i should compare the center of gravity on this bike to the CG of the Venom GPV-1

the way i measured the CG on the E-zip , with the bike assembled and the batteries in place , i laid the bike down on its side , and found the spot where the bike would balance up on a small block of wood ( 3/4" X 3/4" )

with the Venom , I had the bike together as it would be , Battery and rider , and laid it on its side , and balanced it on the eraser end of a pencil

to compare these points , i used the line between the axles of each bike as a reference line and then measured the distance above this line that both CGs were located

since the E-zip is scaled off the GPV-1 , i think the bikes can be compared like this

the axle to axle length of the E-zip is 736.6mm and the height of the CG above this line is 88.9mm

if you look at the two axles and the CG point as a triangle and then compare ratios , for the E-zip you get 736.6 / 88.9 = 8.28

for the GPV-1 the axle to axle is 185mm and the CG is located 26mm above this line , it works out to 185 / 26 = 7.11

this all works out to the E-zip CG would have to be 1/2" higher for the two bikes to match , or surprisingly the E-zip CG is lower than the Venom's

what is deceptive about the side view of the E-zip , the backbone of the frame is sloping down from the stem at a 22 degree angle , and even though the battery is mounted in the top of the frame , it is lower than it looks

compare this to the GPV-1 , the back of the frame is up above the stem , where you have servos mounted and of coarse the rider

here are two side views comparing the CG of both bikes
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 10, 2012 at 08:50 AM.
Reply With Quote
Old Mar 11, 2012, 04:41 AM
scaulfi is offline
Find More Posts by scaulfi
Big thrills w/o hospital bills
scaulfi's Avatar
Brisbane, Australia
Joined Sep 2003
3,761 Posts
Cool, I see where your coming from, I do the same thing when making a 1/5 chass, I use/copy the geometry to work out good CofG.. But the battery in the Vemon is the heaviest thing, in any RC bike really. Personaly, Ive always thought the CG of the venom was a bit high.

As it looks now with your chass, if you were to run the bike as it is now I can see that if you were to make a hairpin turn at a lower speed it will fall to fast and/or slam the bike onto the scratch bars and be unstable thru the turn etc. You would also then need the beef up your steering springs to compensate for the top heavy weight of the bike at slower speeds. It would be great if you could have the batteries mounted onto an adjustable tray that you could move up or down etc to find the sweet spot and not have them in a fixed position just yet. Im thinking they need to be down at the motor level.. But thats just how I see it from this end..

Overall tho,.. I think its going to be a fun large scale bike to run. The wheels and tyres, even the job you've done with the forks, looks great..!
scaulfi is offline Find More Posts by scaulfi
Reply With Quote
Old Mar 11, 2012, 07:22 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Hi scaulfi

when i finished installing the battery tray , and stepped back to look i was shocked at how high the battery looked , and i have spent the last four days in denial , trying to justify it , and going over the design steps i had taken

the great thing about being able to share ideas on these forums , i find , or for me at least , is a lot of ideas occur to me as i am trying to explain what i'm thinking to others

so yesterday after posting back to you on the CG , i was looking at the layout of the bike , and finally saw what had tripped me up , in thinking the batteries could not go below the motor

i had set the rear swingarm up level with the motor in front of it , and thought " well you can't raise the motor because of the swing arm "

it didn't occur to me that the motor and swingarm could be raised together until yesterday

so here is a sketch , to scale , of the parts in what is probably a better layout

i am guessing this would put the CG right about at axle height , can the CG of a bike be too low

thanks again for your input , best regards
mCP_X is offline Find More Posts by mCP_X
Reply With Quote
Old Mar 11, 2012, 08:00 AM
scaulfi is offline
Find More Posts by scaulfi
Big thrills w/o hospital bills
scaulfi's Avatar
Brisbane, Australia
Joined Sep 2003
3,761 Posts
Yes it can, you can have to much that you need more imput to make the bike turn at higher speeds, but the stability would be great. Its all about finding that sweet spot, thats the key.

Do you have to keep the batteries in-line. I was thinking if you can at least keep most of the batteries down low where you've drawn them but move 1 or 2 of them up one level higher infront of the motor. (just to be clear tho, do you have 6x6v batteries or 3x12v batteries in series?) For example if you have 6x6v batteries Id keep 4 under the chass and 2 up infront of the motor, and for 3x12v Id keep 2 under the chass and 1 infront of the motor etc. Having the ability to shift them around till you find that spot where the bike handles nice at all speeds.

Btw, it looks like you may need a little more clearence behind the front wheel for the crash-back mechanism to work and not damage the batteries in the event of a crash..

Im more of a lurker on the forum these days but when I see something I realy like I comment on it..
scaulfi is offline Find More Posts by scaulfi
Last edited by scaulfi; Mar 11, 2012 at 08:36 AM. Reason: Btw,..... added
Reply With Quote
Old Mar 11, 2012, 08:08 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Hi scaulfi

Thanks , the battery is 3 cells , and it would be easy to break into two or three pieces , so having one cell in front would be easy

i am new to RC bikes , i understand the principles but i don't have any practical experience , so your taking time to respond is really appreciated

i have been having a blast building , and see now time spent modeling the parts in CAD would probably be time well spent

thanks again , best regards
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 11, 2012 at 06:21 PM.
Reply With Quote
Old Mar 14, 2012, 10:18 AM
mCP_X is offline
Find More Posts by mCP_X
Registered User
Joined Mar 2011
173 Posts
Hi
I spent about four days looking at the frame and battery box , telling myself over and over , that it was OK

And the more i told myself , the more i knew i was going to have to change it

So yesterday i took a cutoff wheel to the frame and knocked it back into last Wednesday

Here is the reconfigured frame , with room for two of the cells underneath the motor and one in front of the motor , i will post another photo when the battery trays are in

i can say i am a lot happier with this configuration , it was well worth the time to get it right , and want to thank scaulfi again for his input on this
mCP_X is offline Find More Posts by mCP_X
Last edited by mCP_X; Mar 14, 2012 at 10:47 AM.
Reply With Quote


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Icharger 3010b w/1000 watt 24v P/S ---sold! tbird911 Aircraft - Electric - Batteries & Chargers (FS/W) 7 Mar 22, 2012 09:09 AM
Help! HK DG-1000 w/scale pilots tlar633 Scale Sailplanes 8 Mar 05, 2012 10:53 AM
Sold Two AR8000's... One with TM 1000 kc135boomer Aircraft - General - Radio Equipment (FS/W) 3 Feb 28, 2012 04:55 PM
Sold Sharon Pro 3.7 with 2.4 Installed Lower Price $1000.00 orbitone Aircraft - Sailplanes (FS/W) 3 Feb 27, 2012 04:13 PM
Video dg 1000 electrc conversion egall232 Sailplane Talk 0 Jun 12, 2009 03:33 PM