Honda MT50 road legal conversion

spata

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Joined
Jan 26, 2013
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Been lurking here for a while and I thought I would share my road legal E-bike build.
It was only finished a few days ago, so testing is ongoing. The bike is fully road legal (in the UK).
The bodywork is still just gelcoat finish at the moment. Specs are:

Frame:Honda MT50 (1993)
Front wheel: 19" x 1.6" rim - 2.75" tyre
Rear wheel: 16" x 1.6" rim - 3.00" tyre
Motor: Turnigy C80100 - 130kv (with temperature controlled cooling)
Controller: Lyen 18FET
Batteries: Lipo 15S 4P (nominal 55.5v - 20ah)
2 stage reduction
Primary: 14T front – 45T rear
Secondary: 13T front – 60T rear

Speed: approx 30-33mph
Target range: 10-15miles

View attachment 2
MT50-side.jpg
MT50-batteries.jpg
 
Thank you. The bike is surprisingly good. It is much quieter than I was expecting and the ride is really good. Most of the initial work was done with a 10S Lipo set-up so I am being a bit cautious with the 15S set-up till I know everything is ok.

I have got the phase amps set low at the moment so the acceleration is more like a normal moped. It is pulling just under 3kW at 30mph and the cooling seems to be keeping the motor windings below 60 degrees C... so far so good!
I have full data logging at 1 second intervals to an SD card so I can analyse what is going on.

The bike weighs 75.5kg so it is relatively light (original donor kerb weight is 89Kg). The bike was built specifically for the road so no plans to use it off road. The forks are very basic and would definitely not be up for any real off road use.

Having said that the original test mule I made was used off road and that had appalling forks - they would bend after a rough landed wheely - still great fun though!

Test Mule.jpg
 
There are a few things that I learnt doing this conversion which are worth sharing with anyone else thinking of making a bike road legal in the UK.
I apologise to all of you not in the UK as most of what follows will make no sense at all - just think yourselves lucky!

1. Start with a registered donor vehicle and make sure it is the correct body type and taxation class you are going to need.
For example the body type on the Honda MT50 is "moped" that means it is limited to a top speed of 30mph if registered before 08/08/2003.

2. Get the vehicle registered in your name before you try to change anything

3. Download the MSVA manual https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/366046/msva-manual.pdf
If all else fails and you need to go through an MSVA test then at least you know the rules, you will also find the various power limits - for example maximum power for Electric Moped is 4Kw.

4. Do not do any major frame modifications and try and keep as much of the original doner bikes, frame, wheels, forks, suspension as possible.
Then, if the DLVA do ask for an inspection they use a points system to work out if the vehicle is radically altered or not, and you should get away without an MSVA test. Once you are road legal you can always swap over to different components - forks, wheels, etc

5. It took me about 5 weeks to get the V5 changed, I had the bike nearly ready to use - just in case the DVLA demanded an inspection.
You can do this whilst the vehicle is on SORN. All the details you need to fill in are in section 7 of the V5 "changes to current vehicle"
change "type of fuel" to Electric
change "Cylinder capacity (cc)" to 0 - this one is most important do not put N/A or leave it blank or you will still have a gas engine!
Change "Engine number" to your new number - put an engine plate on your electric motor if it does not have one.

6. Send the V5 off to the DVLA with a covering letter. In it I stated:
"This vehicle has been converted to run on electric fuel, this is the only form of propulsion as there is no longer a petrol engine fitted to this vehicle. The original petrol engine has been removed and and electric motor fitted in its place". This is because the default assumption seems to be that it is a hybrid.
I also detailed what the motor power was (which I also have on the engine plate). You need to send them documentary proof of the purchase of the motor (receipt etc). I also included pictures of the motor installed in the frame.

7. DO NOT try and change the "Tax class" this is something that only the DVLA can do when you actually go to tax the vehicle. Having said that mine came back with the tax class already changed to ELECTRIC M/CYCLE

I got my V5 back in 5 weeks with no further communication from the DVLA at all. No inspection - nothing, just a V5 for an electric moped, which I think is a real result. The final hurdle is to get the MOT done, here again they have to enter the cubic capacity to 0 in their system. The guys that did my MOT had to do it as the first thing they did in the test as they could not enter it at the end of the test. Print this info sheet out https://mattersoftesting.blog.gov.uk/how-to-test-an-electric-bike/ and give it to your MOT tester.

There, I think that is all the salient points, I searched a lot around the forum for this type if information and it was thin on the ground, so hopefully this will help anyone else trying to convert a bike in the UK.

- Spata
 
Cool to read what's involved elsewhere!

I just got my scooter on the road recently, we are a British colony so have our own set of "rules" I imported the two second hand bikes from the UK.

I did make a mistake in some ways of not putting the bike in my name first, but to do so would have been a lot of work as it was in poor shape and a non runner missing many parts.

I used paperwork of a previously on the road e scooter and convinced the examiner the new motor was of the same class which it was.

It took all day to get through but was happy when it did. He did ask for bill of sale but all I had was some DLVA paperwork with names of the previous owners. I see Aussi guys have to get an engineer to certify it which costs a pretty penny! :shock:
 
spata, that's a great job, I have a 80100 which I bought way back and never got round to doing something like this with. Now im looking to upgrade my Emax 110s moped controller to 11kw which will take it out of the 4kw moped class but under the limit of a 125cc. Will have to declare all this and do the msva thing but I am confident that if it looks professional and performs well that I should be ok. I'm up near Manchester, are you anywhere near?
 
Hi whereswally, I am in Surrey, so not very close I am afraid. You might be ok just changing the class of your Emax so it is no longer a moped. I would try to stay away from a MSVA inspection if you can.

Scottydog - I took a look at your converted scooter (very nice by the way) and I was very envious at the space you have for batteries. I looked at running a hub motor, it makes the build much easier, but I wanted to see if I could make something that looked to the rest of the world like a regular motorcycle.

Originally I had hoped to keep a lot of the original bodywork from the donor bike, but in the end I had to build fibreglass moulds for tank cover, seat and rear mudguard. I had to cut the original tank mounts from the frame and weld on some more attachment points.

MT50-Frame mods.jpg

Then this lot attaches to the original engine mounting points and the new attachment points.

MT50-Block.jpg

The main parts are the motor assemble which mounts to the original Honda engine mounting points. This is self contained and if I want to change the motor in the future I just need to make a different version.

MT50-Motor secondary side.jpg

Next up is the front battery tray, this holds 4 off 5s 5ah lipo battery packs on each side. One of the reasons I chose the MT50 frame is it facilitates this type of battery fitment and makes access relatively easy.

MT50-Front battery tray.jpg

Last is the electrics plate.

MT50-Top electrics plate fitted.jpg

This holds controller, contactors, BMS, multiple arduinos and a whole mess of wire. The whole assembly can be seen here.

View attachment 1

Final picture shows the split mould I had to make for the tank cover, which covers all the electrics and is relatively weather tight.

MT50-Tank.jpg

I have similar moulds for the rest of the bodywork.
- Spata
 
spata said:
Hi whereswally, I am in Surrey, so not very close I am afraid. You might be ok just changing the class of your Emax so it is no longer a moped. I would try to stay away from a MSVA inspection if you can.

Scottydog - I took a look at your converted scooter (very nice by the way) and I was very envious at the space you have for batteries. I looked at running a hub motor, it makes the build much easier, but I wanted to see if I could make something that looked to the rest of the world like a regular motorcycle.

Ha ha you are in Surry eh!? I just passed through 2 weeks ago on the train from Reading to Redhill! Was down in Cornwall to see a friend.

For sure lots of space, that was the pure reason to choose that model scooter and then go through the trouble to ship two of them 3500 miles! :?

The first one is using the hum drive, but the second one I want to fit a nice motor and belt configuration.

Those new pictures show the level of detail and workmanship I can appreciate! Great job! I agree with the mould making, most of my bikes I have made moulds to make spare bodywork as shipping spares from Europe is crazy expensive!! :shock:
 
Beetbocks, you must be looking at another build. I have a full working 12v lighting set, horn etc.
see:-
MT50-front-lights.jpg
I have 2 12V DC-DC converters running off the battery voltage (nom 55.5v). These are the dead cheap Chinese jobs you find on ebay, but they seem to be working fine. I have one dedicated to all the Bike electrics - lights, horns, indicators, etc. And one that runs the rest of the electronic systems.
The DC-DC plate is at the back of the front battery tray.

MT50-DC-DC-plate.jpg
As for the insurance it was a bit of a nightmare to sort out, I could only get one company - MCE - to quote. It cost £180 which is really expensive for a moped, I have no idea how much it would have cost me in it's original form as I bought it specifically to convert. If you are interested there is a thread discussing insurance in the UK here https://endless-sphere.com/forums/viewtopic.php?f=10&t=69596

- Spata
 
sorry my mistake..it was the test mule i was looking at..
I had heared the same thing about insurance..i have a modified moped that i used to commute -that i can insure for £59 a year (yeah im old and apparently a safe rider- lol) ..its really whats putting me off the conversion..
its a shame as it seems to hold back the use of e-bikes
i use the same dc convertors on my skateboards..very effective..:)
overall a very nicely put together conversion..
 
Finally got round to getting some data logging done

Journey was 4.7 miles and lasted just over 12 minutes

Ambient temperature: 22 degrees C
Max FET temperature: 44.5 degrees
Max Stator temperature: 57.4 degrees

So I am very pleased with the forced air cooling solution I am using for the motor

Max speed: 34.3 MPH
Average speed: 22.8
Average Energy: 61.4 Watt/hours/Mile
Peak power; 3.8kW

MT50_Data_Plot.jpg
The only thing that really surprises me is the current waveform. The only bit that looks correct is around the 3 minute mark where I am doing a steady 32 MPH.
I am guessing the wild fluctuations seen elsewhere are because I am using an ACS758 and only sampling once a second and not doing any filtering, I guess I will have to take a look at that.

Does 61 Watts/hour/Mile sound about right, for a 75kg moped or is it way out of wack?

- Spata
 
This is one of the best conversions I've seen. How much do you weigh, spata? 61Wh/mi. seems on the high side for just three stops, even if the accelerations were rapid.

[EDIT] I didn't see the 3.8Kw peak. 61 is probably about right, then.
 
My weight is about 80kg, so all up around 155kg.
I just looked at the data again and the average for the run was 1.4kW.

I thought 61 Watt/hour/mile seemed a bit high as well. So I am interested in finding out what others are getting for moped type conversions.

- Spata
 
Thanks Riba, If I convert to wh/Km I get 38wh/km about the same as your WOT figure.
I took another look at data from a longer 12 mile run and on 1.2 miles of flat road WOT (about 33 mph) I am around 56wh/m (35wh/km).

My riding is in urban traffic conditions with frequent start stops, so I guess the constant acceleration and braking are messing with the efficiency.
I assume your measurements were taken using the HPM5000 motor /Kelly controller combination on your Tomos conversion? (nice job by the way!)

- Spata
 
Put a video clip together of some helmet camera footage overlaid with an animated portion of the datalogging file
Thought this might be a good way to present the data.

[youtube]lsqeNxu_-Xc[/youtube]

- Spata
 
Nice build ! most certainly an ES gold member !
Perhaps your average energy @61.4 Wh/miles is a somewhere a bit high, I think you should add 1 gear for more end speed.
 
A virtual beer goes to jpgey, thanks for the gearing suggestion.
The gearing was originally done to keep the power and speed within the legal limits of the moped definition here in the uk.
I just did a no load run. I came out with a maximum speed of 35.1mph.
If I do a bit of correction for voltage differences for my datalogged run I end up with the bike going only 6% less than that when on level ground.

The motor efficiency drops off after about 80% of no load speed, so that may be why the wh/m is higher than expected.
The good bit is that the bike does not really slow down much on inclines - the whole idea was to make sure I stayed in the high efficiency region on hills so that I had no overheating issues. That bit at least seems to be working and I do not mind sacrificing range to keep everything cool and predictable.

Having said all that I have just changed from a 13 tooth secondary drive to a 14 tooth, the speed has gone up as expected, now I will need to get some more datalogging done.

Thanks again,
- Spata
 
Very nice clean build. 61 watt-hours/mile seems reasonable. Moped tires are not very efficient compared to bicycle tires. My Borg has similar weight but has pedals so you can really feel the resistance compared to pedaling a mountain bike. If I ride it hard in hilly country (my commute) I see 50 to 66 wh/mile consumption. The full thread is linked in my signature. 18S 66V 32AH, Cromotor, Sabvoton controller, Moped tires and rims. Not quite a moped but a heavy electric bike with Moped wheels.
 
Well I got some results from my gearing change. Basically going from a 13T to 14T drive sprocket made very little difference to the Wh/mile.
It did however increase the top speed and decrease the acceleration - pretty much as expected. I then played around with the phase amps to get back to about the same acceleration and dropped the speed back to around 33 mph by setting the controller to 94% speed and now I am up at 66Wh/Mile (up from 61Wh/mile).

The bad news in all this is that better top speed is definitely useful, it brings the bike more in line with UK road speeds.... So now I am in a quandary as to what to do. It will stay at 14T for the time being with the controller at 94% speed, then when my energy counter reaches a predetermined point I will switch to 99% speed. That way I get more uniform top speed regardless of the state of battery charge.

I also get some datalogging on the effectiveness of the fan cooling I am using on the motor. I have started another thread here if anyone is interested in the details. Bottom line is that I am reducing stator temperature by around 17-20 degrees C.

- Spata
 
Classic Motorcycle Mechanics magazine have just published an article about my bike.
If you are interested it is a 4 page spread, starting on page 60 of issue 360 (October 2017) which came out today.

The piece is about a "READERS SPECIAL" and they were really interested in running the article.... it just goes to show that the mainstream motorcycling press is interested in what we are up to!

I have managed to find the magazine available for free download here:Magazine Download just click under where it says "Size: 70.02MB" and it will download the whole magazine!

As a teaser here is how the bike looks now.
Optinn_2.jpg
- Spata
 
What a nice conversion with all that custom made parts. I wonder if it was hard to get it again road legal?

spata said:
Classic Motorcycle Mechanics magazine have just published an article about my bike.
If you are interested it is a 4 page spread, starting on page 60 of issue 360 (October 2017) which came out today.

thumbs up :)
 
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