1980 Honda Express Electric Conversion

pepep

1 mW
Joined
Oct 15, 2018
Messages
13
Location
Madison, WI
Hi Everybody!

Long time lurker here so first, thank you to every contributor to this site. It helped me tremendously with my first build: a cooler go kart which I am currently writing up the build thread for - [youtube]https://www.youtube.com/watch?v=7XJTyHLPJzo[/youtube]

This project sort of fell into my lap. I met a guy who was into rebuilding vintage Honda Express, Urban Express, and Yamaha QT50 scooters. I asked him if he ever thought about making an electric moped and stated I had a little experience from my electric go kart. He was really interested and a short while later, he messaged me saying there were two Honda Expresses for sale about an hour away for $500 total so we went in together and purchased them. Here's mine ( the gas an oil was all drained before I brought it inside):

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Disassembly:

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The original electric system is 6V but wanted to change everything over to 12V so it would be easier and cheaper to find a DC-DC converter and finding LED lights would be easier. The battery had also died which blew many of the existing lights out. The keys to the scooter were lost at some point (and later re-found) so it was hotwired, some cables were cut/frayed, many connectors were corroded, covered in oil or in otherwise poor condition, and a lot of wiring layout needed to be changed anyway so I decided to rip out and rebuild the wiring harness.

IMG_20181203_231736.jpg

I want to try to change the sealed beam headlight over to an LED headlight. I bought a cheap H4 style LED headlight on ebay which I will attempt to retrofit in the sealed beam carcass. I will only use this if I can focus the headlight beam properly so I don't blind everyone.

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I needed to fix both brake switches.

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I am currently trying to find a way to use the original Honda Express throttle grip on a hall effect throttle. It doesn't look like it's going to fit on this cheap twist throttle I bought. Does anybody have any suggestions for hall twist throttles which easily interchangeable grips?



Engine disassembly.
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Here is where I an currently stuck. My current plan is to use the original "transmission" which is a single speed reduction of 14.22:1. I need to change this ratio to something like 6:1 if I want to use the Revolt RV-100-PRO motor and bump the top speed to 35ish MPH. The chain in the transmission is extremely unusual DID270H chain so I will have to machine a new motor sprocket and modify the housing. I was hoping the motor would fit in the existing crankcase which some modification but it is now clear it will take more than SOME modification..half of the crankcase will have to chopped off to fit the 100mm diameter motor and then restrengthened. I'll take some pictures later. I am not a huge fan of the friction that's going to be going on in the "transmission" but it will maintain the original look of the scooter.

My other option is to build a new swingarm and find a 14" wheel hubmotor which sounds like an equally exhausting process.

Let me know what you think!
 
Nice project.

Don't bother with the revolts. They have thick old laminations and underperform by a magnitude because of it.
with a 14:1ish ratio, a super duper fast RC motor would be just the ticket.

Or a very fast wound hub motor!
 
If you haven't bought the revolt motor yet then please! Don't!

Several members here including me have bad stories with revolt motors.

I'd pick a QS 1000/2000/3000w mid drive motor instead. it's far superior.

Apart from that: nice project :D
 
Thank you both for the reply!

I'll certainly expand my horizons. I used a RV-120-Pro for my go kart and, without being able to compare it to other motors, the thing just feels so powerful. The RV-100 does use thinner lamination than the 120 which I thought would help but in talking with Alexey from Revolt, He did say the max RPM for the RV-100 should be 3000-3500 RPM which was disappointing.
 
The QS motor is probably overkill and is extremely heavy for the amount of power it puts out.

That being said, i don't have a better recommendation since i have not done the research on chain drive motors today.
Look for a dyno sheet though.

Revolt has refused to provide a proper one for a reason.

The sur ron motor's power to weight ratio does look pretty desirable.
 
larsb said:
I'd pick a QS 1000/2000/3000w mid drive motor instead. it's far superior.

Apart from that: nice project :D

Thanks for the kind words! Those motors look amazing but I only see the 1000/2000W variants in swingarm assemblies and the 3000W in a kit with controller with $200 shipping from China!?!?

neptronix said:
Revolt has refused to provide a proper one for a reason.

THe new "-E" variants of motors have better data provided but yeah, you're right, I should look for something with better documentation.
 
neptronix said:
Nice project.

Don't bother with the revolts. They have thick old laminations and underperform by a magnitude because of it.
with a 14:1ish ratio, a super duper fast RC motor would be just the ticket.

Or a very fast wound hub motor!

Thanks!

Would something like a C80100 be enough for something like this? I want this to be more responsive and fun than the original scooter and don't want to skimp on something like this. "If it's worth doing, it's worth overdoing"

I have found a single hub motor with a 14" wheel size http://www.leafbike.com/products/di...casted-hub-motor-bike-conversion-kit-946.html but comes in a kit, is rated for 48V/1000W and I'd need closer to 60V to spin the thing to 35+ MPH. Plus, I'd then have to design and build a new swingarm :(
 
Just send a mail to QS about what you're looking for. They sell the motors separately or with matched controller also. I bought my 3000W with controller for 367usd on sale.
I think it's too big for your scooter so the 1000w or 2000w would be better.

Don't be fooled by the low power numbers. I've run 15-20kW through the 3000w qs motor :bolt:
 
I don't know about the C80100 from experience, but you could probably find plenty of threads about it using the google search option above.

I am sure that you could order the leafbike motor as a separate item and pair it to a better programmable controller.

I am sure there are better scooter hub motors out there though. Leaf's 1500w model produces quite a lot more power for only 2lbs of weight more, and hits peak efficiency at about 30mph and would have scads of extra headroom to go up to 50mph or more for short periods of time in such a tiny wheel if you wanted to get crazy.

Peak efficiency on the 1000w motor would correlate to about 25mph, which is good if that's the speed you want to travel at most of the time.

A better motor would be one that has a lower pole count and razor thin laminations. Look up the hubzilla motor from john in CR as an example of an EXCELLENT scooter hub motor. :)

You could probably just design dropout adapters and use a bike or motorcycle hub motor without needing to reinvent the rear swingarm entirely. It would be less machining than adapting a RC motor to the existing transmission.

Upsides to a hub:
easy install
simple and inexpensive controllers can be used
cheap to buy
don't need to add hall sensors.

Downsides to a hub:
Heavier per watt outputted
Possibility for lower overall efficiency than a chain driven motor if a subpar design is used.
Negative effects to the rear suspension due to unsprung weight
Easier for the wheel motor to intake water during operation, especially in a scooter where the wheel size is very small.
 
larsb said:
Don't be fooled by the low power numbers. I've run 15-20kW through the 3000w qs motor :bolt:

That is nuts! The QS 1000 is moving towards the top of my list.

You could probably just design dropout adapters and use a bike or motorcycle hub motor without needing to reinvent the rear swingarm entirely. It would be less machining than adapting a RC motor to the existing transmission.

The issue here is that the transmission is the swingarm which is typical for scooters and mopeds. I'll start sketching up a swingarm in Fusion360 to see if its something I would feel would e easy enough to make.

That hubzilla would be an absolute blast! Thanks for all of those rough estimate for power/speed.
 
One way or another, you pay for shipping, looks like a great price to be paying $150 shipping for.

I have some of the c80100 and c8085 laying around, they're difficult to use. With that swingarm you can skip ripping around that engine you've already done much of the work on.

These guys are in the wiki, dang, a chance for someone to use the wiki. https://endless-sphere.com/forums/viewtopic.php?t=65972&start=925#p1235435
 
Thanks for the link to QS's sale page.

You're absolutely right about shipping...I have clearly been spoiled for too long with "free" on everything from China. $270 for this motor is great. Had I seen $275 with free shipping when I first stumbled upon it, I would have jumped on it right away without much thought. :lol:

I ordered the QS 1000W 90 tonight. The overall diameter of 110mm is conveniently the exact diameter of the Honda Express clutch and right around the same diameter as the original generator bell. Significant rework of the crankcase will still need to be done but this at least will save a tiny bit of headache I hope.
 
I cancelled by QS motor from Aliexpress sine I think I may be able to get the motor cheaper straight through http://www.cnqsmotor.com/en/

I sent an email to http://www.qs-motor.com/ and got a quote for $120 for the motor + $85 shipping before learning that :warn: THIS IS NOT QS MOTOR'S OFFICIAL SITE :warn: .

So now I'm waiting to hear back from the official site http://www.cnqsmotor.com/en/ about prices.
 
larsb said:
I ordered some stuff from http://www.qs-motor.com/ a while ago but eventually had to cancel the order after a looong wait for nothing.. You did the right thing!

Thanks for the reaffirmation here. I'd be so stoked to get this motor for right around $200 but that seems next to unbelievable.
 
Just a quick but exciting update! I was able to contact QS Motors directly. They sold me the QS 1000W Mid Drive for $125 + $86.70 for shipping +$10.06 PayPal fees = $221.76! Not too bad I'd say.

The invoice says they add 4.4% + 0.3 for paying through PayPal which is higher than PayPal's actual fees and, for this order, that only comes to $9.35. So something is a little funny with their fee structure but I'm not going to worry about it until this thing doesn't show up for months.

Other than that, progress has been slow because of the holidays. I have made a little progress with the wiring and hope to test the blinker and lights switches soon with the wiring harness in the scooter.
 
I was not able to spec anything out. No sprocket or pulley customization, no custom shaft, or kV. It may come with an 8mm pitch pulley on it according to other ES threads. I was told the maximum RPM was 3,450 at 72V. It sound like more customization may be allowed with the 2000W or 3000W variants

Damon at cnqsmotor.com told me If I want higher RPM, the 3000W variant is rated at 3800 RPM without flux weakening but up to 6000 RPM with flux weakening. I'm not to familiar with flux weakening but I don't know why I wouldn't be able to eek out a little more speed with flux weakening on the 1000W version.

The price is good enough that I can use it as almost an experiment. I was planning to use a ~48V setup but that will need to be bumped up now. I'll also need to machine a new shaft for this motor so hopefully tear down isn't too bad.
 
My buddy has a few Honda Expresses and we'll definitely go with an RC type outrunner rpm and keep the original reduction system. The small size and steering geometry make it something I wouldn't want to exceed 30mph on. It would be short distance errand runner, so enough RC lipo to get to the necessary voltage will hide nicely under the seat for an even cleaner than original look.

I look forward to seeing how yours turns out, since fabbing a swingarm is simple and then I could also mod the geometry enough to make it safer at higher speed as well as put a real motor on it. Going that route I'd go for a lot more battery with much of it between the pegs and forward toward the headtube, so the battery housing stiffens the main tube that to me is suspect.
 
Dauntless said:
So how did QS respond?


Sorry, I have been distracted by other stuff recently. The motor came in the mail in less than a week! Really fast shipping. I haven't even had the opportunity to put in on a test bench though. I'm hoping testing will happen next week and then a tear down.

John in CR said:
My buddy has a few Honda Expresses and we'll definitely go with an RC type outrunner rpm and keep the original reduction system. The small size and steering geometry make it something I wouldn't want to exceed 30mph on. It would be short distance errand runner, so enough RC lipo to get to the necessary voltage will hide nicely under the seat for an even cleaner than original look.

I look forward to seeing how yours turns out, since fabbing a swingarm is simple and then I could also mod the geometry enough to make it safer at higher speed as well as put a real motor on it. Going that route I'd go for a lot more battery with much of it between the pegs and forward toward the headtube, so the battery housing stiffens the main tube that to me is suspect.


Fabbing a swingarm is looking more and more enticing but I really want to keep the stock look just for the sake of it. You're right though - past 30 starts to get a little sketchy with the steering and drum brakes. Gearing it to 35-40 just means the motor isn't at or near WOT while putting around at 25. Most of the roads I envision taking this on are 25 MPH which means 30+ is needed at times to safely keep up with traffic unfortunately too.

For the sake of this project, RC motors with minimal changes to the gear reduction maybe do make the most sense rather than what I'm trying to do. This QS motor is larger than something like an 80MM outrunner so more case modifications need to be done and it will only spin 1/2 - 1/3 the speed as something like a C80100.
 
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