50cc auto scooter conversion to electric (with video)

[gwhy!]

This project is very interesting.

Thanks, captain
Its something that I have wanted to play with just to see how it goes.

I have a couple of Yamaha scooters and some spares.. I'd send some rollerz to get this rollinz but I'm so far its not worth the freight! I assume that backlog of flights thing is over by now?

Cheers vanilla,
I shouldn't have to wait to long for the rollers, I'm hoping they will come today, if not tomorrow. Thanks for the offer thou.
Yes I think the flights are back to normal now but as regards a back log its anyone's guess.

 

[gwhy!]

Update:
At last the new rollers came today, I ordered the stock oem rollers for this scoot and they are lighter than the ones that will be replaced so maydaverave will be happy
View attachment new rollers and brake pads.jpg

As you can see I also got some new rear brake pads ( I think it needed them )
View attachment 1

So the new rollers are fitted, new brake pads are fitted and the batterys are charged.


If the weather holds up tomorrow I will be doing some testing and some video will be uploaded
But I will warn you the motor don't sound pretty, I think its resonating through the mount and using the crank shaft space as a boom box :lol: But again this can all be sorted out in due time if its a go'er.

 

[Jay64]

nice, thanks for the updates and the pics. gives me hope to try it out on the non runner I got sitting in my shop. Are you going to end up putting a plate over the opening for the piston, or just leave it open?

 

[gwhy!]

nice, thanks for the updates and the pics. gives me hope to try it out on the non runner I got sitting in my shop. Are you going to end up putting a plate over the opening for the piston, or just leave it open?

Hi Jay64,
I may try and rig up some sort of blower ( a fan in the center of the modded crankshaft ) and using the carb and crank opening to direct the air flow to the motor for some forced air cooling.

 

[Arlo1]

Cool I want to see how this goes.

 

[gwhy!]

[youtube]CoNd1rq0c3M [/youtube]

The batterys just would not cut it, as I ran them down quite a bit before this video the power never exceeded about 2kw in this video, The big torque spring on the rear pulley is to weak so the belt is slipping but as it stands it pulls and runs just like a restricted 50cc gas scoot ( but will run up to a higher speed i guestimate around 35-40mph with the slipping belt ) I hope to get the scoot to a private road over the next couple of days to test current top speed and efficency, I need to sort out the saggy bats and the torque spring which will improve the pulling away power by loads. I am very pleased so far with how it behaves, and there is another 4kw to get out of this thing before I start pushing the limits

 

[Arlo1]

How heavy of rollers did you go with? I would be tempted to start with the heaviest possible.

 

[Arlo1]

Did you test it on the road? The rear clutch has shoes to let it slip to a certian rpm. I would put weaker springs in there and it will grab at a lower rpm.

 

[gwhy!]

The rollers are around 4g ( i didnt weigh them before i put them in ) They are the stock ones for the scoot. Yes I think heavy rollers will a much better option it will also help with the belt slippage as well as giving a much better acceleration . I thought I would go light first to try as its easier to increase the weight of rollers without buying new ones. I may up the weight to around 6g and give that ago before messing with the torque spring. The intresting thing about the variator setup is it seems to be vary constant with the power, the more load you put on the motor the current draw hardly goes up, Even with the back wheel locked the whole thing still only drew 40A ( but this is down to belt slippage im sure ).

Edit:
Weaker springs has already been fitted and the clutch grabs at around 3.5k motor rpm. At the momment this seems to be quite a nice launch rpm ( it was around 6k motor rpm with the springs that was in the scoot when I first got it )

 

[Arlo1]

The rollers are around 4g ( i didnt weigh them before i put them in ) They are the stock ones for the scoot. Yes I think heavy rollers will a much better option it will also help with the belt slippage as well as giving a much better acceleration . I thought I would go light first to try as its easier to increase the weight of rollers without buying new ones. I may up the weight to around 6g and give that ago before messing with the torque spring. The intresting thing about the variator setup is it seems to be vary constant with the power, the more load you put on the motor the current draw hardly goes up, Even with the back wheel locked the whole thing still only drew 40A ( but this is down to belt slippage im sure ).

Edit:
Weaker springs has already been fitted and the clutch grabs at around 3.5k motor rpm. At the momment this seems to be quite a nice launch rpm ( it was around 6k motor rpm with the springs that was in the scoot when I first got it )

Awesome I think if you can mesure acuaratly enough you could fill the weights with solder and drill them to the weight you want. I know the price of the weights is not the killer its the time you have to wait for them. The front clutch sometimes has a small shim in it you can remove sometimes for more clamping force and higher top speed!

 

[maydaverave]

It lives 8) I think it might be cheaper to build one of these than a decent ebike. I think this qualifies as a sucessful experiment.

 

[gwhy!]

It lives 8) I think it might be cheaper to build one of these than a decent ebike. I think this qualifies as a sucessful experiment.

8) Yes it lives.. and Im very pleased so far
Yes it would work out so much cheaper and very easy to do ( Except for the crank, But I would have thought it shouldn't cost to much for a engineering firm to do modify the crank ). A few observations: If a faster (Higher Kv ) motor was used the transmission prob will not have to be messed with over stock, 3 ways to achieve this would be Buy a higher kv motor, run on a higher voltage or gear the motor to the crank, Ideally a rpm of around 10k rpm at the crank should be a direct replacement for the piston arrangement.

The scoot I have has a total (primary/secondary )gear ratio At the back wheel of 13.5:1 (this is after the variator gearing) This gearing is very nearly the max reduction that can be achieved at the back wheel on a scoot of this size but it is possible to decrease this reduction to about 5:1, so If you can put enough power through the drive train you can end up with a VERY fast scooter .

I have just fixed my handheld rev counter so if the rain holds back tomorrow I will take some real measurments of motor/rear wheel and clutch engagement speed. I will also try and sort something out to measure the efficency of just the variator/belt ( I dont think it is as bad as what some people are saying ) I think the clutch and the weight of the back wheel is the main current sucker in the system .

I will also remove the rollers and weigh them for future reference

 

[gwhy!]

Update:
I took some real measurments today in between the rain.

primary/secondary gear ratio at the back wheel is 13.5:1
lower gear ratio of variator is 2.5:1
upper gear ratio of variator is 1:1.8
actual kv of motor is 162kv
clutch engagement with weak (blue) yam50cc clutch springs was 3000rmp
No load of stand alone motor 5.9A
No load current just through modded crank 11A ( high due to my lack of skills machining )
No load with belt fitted but not driving the clutch 29A ( Ok so its a little worst than I would have thought )
Total No load current though drive train with real wheel fitted and clutch engaged 35~40A and upto speed ( this did not vary even with a stalled rear wheel)

I removed the clutch springs all together ( as John in CR suggested ) And this improved the performance of the scoot a lot, a strong Clutch engagment is now 1000rpm and the scoot pulls so much better ( I think with 3000rpm engagment there wasnt enough revs left from the motor to keep the clutch on a strong engagment so the clutch was slipping and not the belt ) This has now increased the peak wattage output to 2.6kw and just this very small difference ( 600w ) in output power has made a huge difference in launch pull, ( the current still settles down to about 35~40A once rolling and fully loaded )

I seriously under estimated the new roller weight, they are 7.5g I thought the centers were ali but they are brass. I will have to buy some lot lighter ones as a starting point .

Anyway there is not much else I can do for the time being until I get some lighter rollers I may try and get out and road test it soon, but as it is I know from the feel it will behave like a non-resticted 50cc scoot but with a low top speed of around 40mph ( due to the lack of rpm from the motor ) I need to think about upping the voltage I think or re-gearing 8)

 

[vanilla ice]

I vote more volts.

 

[gwhy!]

I vote more volts.

It will be the easiest for sure, I will have to change the caps in my controller and rig up hall sensors to the motor but this will be much less trouble/cost than changing the gearing. I will only be able to run upto 75v as the this is the rated voltage of my fets this extra voltage should push the scoot only upto around 60ish mph, there will be loads of grunt thou if I get the variator gearing right I estimate a 0 - 60'ish should be do'able in about 4-5 secs

edit:
If the gearing is changed at the rear wheel and the motor has enough grunt it could be push nearly upto 90mph

 

[Jay64]

Update:


I removed the clutch springs all together ( as John in CR suggested ) And this improved the performance of the scoot a lot, a strong Clutch engagment is now 1000rpm and the scoot pulls so much better ( I think with 3000rpm engagment there wasnt enough revs left from the motor to keep the clutch on a strong engagment so the clutch was slipping and not the belt ) This has now increased the peak wattage output to 2.6kw and just this very small difference ( 600w ) in output power has made a huge difference in launch pull, ( the current still settles down to about 35~40A once rolling and fully loaded )

Sorry to be so lame about this, but I have never worked on one of these small scooters. I am more of a sportbike guy. Could you possibly take some pics of what you did with removing the clutch springs? What you are saying makes total sense to me, I just don't know how to do it or even where it is on one of these bikes. I'm totally stoked on your build. I have that scooter I was talking about before, but once I realized that the motor was part of the swing arm, I thought I wouldn't be able to do anything with it. I had a vague feeling that I might be able to hook a motor up to the crank as you did, but wasn't sure if it would work. Basically I just shoved the project into the back corner of the shop. Now that I see that you have made it work, I am stoked to get back to work on it. Kinda thinking about hooking one of my AgniMotors up to it just for shits and grins. But I also like the small motor that you used. I was thinking maybe use two motors, one where you attached to, and then have another one connect to the center of the crank by chain to a sprocket through the piston head opening. Could probably weld a plate to the crank, and then bolt a sprocket to the plate.

 

[gwhy!]

Hi Jay
I will get some tear down pics tomorrow of the clutch assembly for you. I know very little about the agnimotors and dont know if it will run fast enough you will need at least 6krpm at the crank to make use of any off the shelf transmission parts. It would be good to see how you get on with yours and we can compare notes . Running 2 motors (like the one I have used) should make the thing fly and is something I have considered ( or maybe one of the 12kw outrunners thats being talked about in another thread ). Keep me in the loop if and when you decide to start playing around with the scoot that you have.

 

[maydaverave]

I really want to try this now. You know if you get six heavy weights and six light wieghts you can use three of each as long as they are across from each other to get a medium wight. Gives you more options. Also you could try a taller tire to get a taller gear ratio if it will fit.

 

[maydaverave]

To see if you should go with lighter or heavier weights you could take three of the weights out just make sure that they alternate, one weight, one no weight. See what that does. Not a permanent solution but will give you an idea of which direction you need to go and how far.

 

[gwhy!]

Update:
I am playing the weighting game again ( what a clever pun that was ) I ordered some more weights .

In the mean time here are some pics
The rollers usually run dry, the back side of the variator just slides of the shaft after the nut is removed.
View attachment variator tear down.jpg
The complete rear pulley and clutch just slide off the shaft after nut is removed.
View attachment clutch and rear pulley removal.jpg
Remove the torque spring retaining nut, go steady when unscrewing this as the spring is under quite a bit of tension.
the clutch springs are already removed from the clutch shoes in these pics ( but there are 3 of them joining the shoes together )
View attachment clutch tear down.jpg
View attachment randoms.jpg

I really want to try this now. You know if you get six heavy weights and six light wieghts you can use three of each as long as they are across from each other to get a medium wight. Gives you more options. Also you could try a taller tire to get a taller gear ratio if it will fit.

I know you can mix rollers but i have nothing to mix them with I only have one set . I dont think there will be no spare room to fit a taller tire this really would be a easy way of upping the speed . From what I have seen so far with a variator setup I think it could be a all round winner. Start looking for a cheap non-runner and give it a go .

 

[gwhy!]

To see if you should go with lighter or heavier weights you could take three of the weights out just make sure that they alternate, one weight, one no weight. See what that does. Not a permanent solution but will give you an idea of which direction you need to go and how far.

Now this is something I could try .. thanks. I will report back tomorrow

 

[maydaverave]

It sounds like you might need heavier weights rather than lighter. I was thinking these motors like high rpms but to get a taller gear ratio you need heavier weights. What rpms are you looking for. To light of weights and your not using the tallest part of the pulley which limits your top speed to heavy of weights and your not using the shortest ratio during takeoff. The cool thing about cvts is how tuneable they are. You don't need to change sprockets to get a different gear ratio just the weights.

 

[maydaverave]

What you could do is run a line down the variator pulley with a permanent marker and see what the belt rubs off. Then you can see what part of the pulley you are using. If there is marker left at the top of the pulley then heavier weights would give you a higher top speed. If there is a lot of marker left at the bottom of the pulley than you might want to go with lighter weights. But since your using a different motor with different rpm range it might be best to use mostly the top or bottom of the pulley but this will let you know what part of the pulley you are using and how much pulley you could use in a taller or lower ratio.

 

[gwhy!]

It sounds like you might need heavier weights rather than lighter. I was thinking these motors like high rpms but to get a taller gear ratio you need heavier weights. What rpms are you looking for. To light of weights and your not using the tallest part of the pulley which limits your top speed to heavy of weights and your not using the shortest ratio during takeoff. The cool thing about cvts is how tuneable they are. You don't need to change sprockets to get a different gear ratio just the weights.

Your quite right about the lighter/heavier rollers but I was thinking along the lines of efficiency the rollers will only ramp up as and when they can instead of being forced to ramp up, they will also react better to rolling load ( shift up and down faster ) but im also hoping that because of the electric motor the difference in power is instant/constant compared to a gas motor this just may also help push out the lighter rollers right to the top of the ramp. But this is a unknown at the moment so some testing will have to be done at max speeds. And yes I have been a cvt convert for the last 15years on gas scoots and to be honest for every day commuting they are the best thing since sliced bread.

Edit:
There is a small cut out in the cover ( where the oil pump used to be ) and you can get a good view of the front pulley I was thinking of setting up one of those little video cams and film the acceleration ramp up of the pulley under a real load when I can get to a stretch of private road to test on hopefully that will be this coming weekend. I should also have my other rollers by then so I can do some swap and test stuff.

 

[maydaverave]

I can't wait to see some video of this thing in action. I know you know what your doing with the cvt but many people on this site are unfamilar with them. Just trying put some information out there for the purpose of discussion.