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Electric Bullet (pipe dream/possible winter project)

Posted: Wed Aug 17, 2022 11:06 am
by stinkwheel
I've been giving serious consideration to an electric vehicle for commuting to and from work. Thing is they seem to be either expensive, slow and rubbish (eg electric bicycle) or very expensive and high performance. No real middle of the road commuters that'll do effectively what a 125 motorbike does.

Looking into the radically modified vehicles regs, it appears if you retain the original, unmodified frame, suspension, wheels and brakes and ONLY change the engine, you don't trigger an SVA test, you can retain the original registration and just register the change of engine.

So, if I did the traditional hub motor, you'd need to do an SVA because you've changed the engine and the wheel and brakes. If I did a stand-alone electric motor with a chain drive to the rear wheel, I wouldn't. Happily, you can buy kits that provide this along with the battery and all the control electronics.

The logical thing would be to find a rolling chassis with a blown engine, ideally a duplex frame which would be simple to bolt a motor to (A Z250/GPz305 springs to mind). However, it occurrs to me that I have a huge stash of enfield bullet parts so if I got a registered frame (our hosts have an Indian 500 frame and V5 on their books right now), I could cobble together enough rolling chassis parts from my shed to make a bike.

Here's the head scratcher though. The bullet frame uses the engine as a stressed member. I'd need to manufacture some stressed members to tie it all together and which will form a base to attach a motor to. I think you could probably just use a couple of bits of box-section between the front and rear engine mounts with a spacer between them and a couple of bracing plates up to the gearbox steady. One of which could even incorporate an outrigger bearing or steady for the motor output shaft.

The electric motor is about the same size as a bullet gearbox so I reckon you'd have loads of room both in front of the motor and where the toolboxes/airbox normally goes for battery storage and I could cut the bottom out of an old tank to house the electronics so you can pop the fuel cap to plug it in.

Given the currently available electric motors, I should be able to fairly easily make something that'll do 60-70mph for 40-50 miles. Increased range is just a case of money and battery storage space but a charge would probably do me a full week of commuting at that. Even an option to use a hybrid voltage so you can run 12v/24v for range vs performance by having batteries switchable between series and parallel.

Cost is a thing. Probably looking at about £1500 for the motor/electronics. Our hosts frame is in at £500 + VAT. There again, you're looking at that much for a half decent electric bicycle which can only do 15mph with a 30 miles range that needs to be pedalled.

Be interested in comments, questions and pitfalls.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Wed Aug 17, 2022 12:10 pm
by Trev
Interesting thought there. I have a Giant electric motor assisted bike and it did indeed cost a small fortune, over £3k (and that was back in 2018) although it is excellent to use and of good quality. My thought is, it depends what your after. If you're looking to tinker and end up with a motorcycle style EV, albeit probably more basic than what's on offer from major manufacturers, then not a bad idea to build one yourself. If you're after just the most cost effective solution to a relatively short commute then it's probably better just to buy one of the '125 equivalent' scooters that are now available.

KYmco do one that's £3200 on the road (obviously you'll get a second hand one for a fair bit less) and although top speed isn't great, acceleration is pretty good and it'll come with all the convenience and reliability of a mass produced product .... if that cuts any ice with you. There are other brands starting from under £2k so on a pure cost basis it probably doesn't make sense to go the build it yourself route.

I've not tried a battery powered scooter/moped but they look like they could be fun, not enough range at the moment for me though.

Keep us posted with what you end up with

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Wed Aug 17, 2022 6:16 pm
by Duke of Wybourne.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Wed Aug 17, 2022 7:44 pm
by stinkwheel
Good to see how he's done that.

Thumping huge set of batteries he's go on there, I think he'll go hundreds of miles on that. I was thinking rather smaller scale.

I've been (very vaguely) looking at these motor kits.

https://www.miromax.lt/en/m-6/c-26/c-50 ... o_products

10hp doesn't seem much but it's pretty much what you get from a standard 350 bullet and electric vehicle HP is different, an internal combustion engine makes that at peak revs, an electric makes it as soon as you start rolling.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Thu Aug 18, 2022 4:35 pm
by Duke of Wybourne.
Stinkwheel.
I have some experience in electric powered bikes. If you do go ahead I would check on insurance, that has been my stumbling block. No issues with the registration etc, but getting someone to insure them was almost impossible. Things may have changed since my last project, but I would still make some enquiries first. I've tried a couple of 125 equivalent electric motorcycles, and in both cases the "quoted" range was grossly overstated. The only company prepared to guarantee range , the last time I looked, were the manufacturer of the electric reincarnation of the Simson Schwalbe, but what you have to watch out for is that a lot of manufacturers quote the maximum range when the bike is in eco mode, which usually means 15mph, and the maximum range also involves having to purchase an extra battery/s. None of this stuff is without problems either. Don't skimp on batteries/charger as the results can be truly disastrous.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Thu Aug 18, 2022 4:57 pm
by stinkwheel
I'll ask the insurance about it next time because my renewal will be up before I get anything built. I have a modified bike policy anyway, I've got my 612 on it with all the very numerous modifications declared.

In fairness, a 20 mile range would be sufficient for what I'm doing.

I was actually inspired by fortnines TC90 build. Now a bullet will be a lot heavier than his donor chassis but he seemed to land up with something very useable for not a huge amount of faffing about. He got 36km at 35mph out of a fairly dinky battery and a bog-basic hub motor.

https://youtu.be/O2zlYpy6QCM?t=299

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Thu Aug 18, 2022 7:38 pm
by Duke of Wybourne.
I wonder how you'd get on using a vintage road registered Cyclemaster type, and swapping the hub powered wheel for a 1500w rear hub motor, It
would give you similar if not better performance than the 35mph motorcycle. The hub motor is the way to go as far as simplicity is concerned.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Thu Aug 18, 2022 9:42 pm
by Adrian
I did see somewhere the beginnings of a project where the electric motor was being installed inside a set of Model J 500 crankcases, presumably it would use the RE primary, clutch and gearbox and could still have the original top end still fitted for cosmetic purposes.

A.

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Thu Aug 18, 2022 10:23 pm
by stinkwheel
Adrian wrote:
Thu Aug 18, 2022 9:42 pm
I did see somewhere the beginnings of a project where the electric motor was being installed inside a set of Model J 500 crankcases, presumably it would use the RE primary, clutch and gearbox and could still have the original top end still fitted for cosmetic purposes.

A.
That did occurr to me, it would be pretty much like doing a well documented diesel conversion then. Although the clutch and gearbox are really surplus to requirements and just a way of sapping power. I suppose you could leave it in top all the time so the gearbox is straight through and just bolt/weld the clutch up... Which would leave interesting possabilities for running it in a classic trial if you stuck it in one of the other gears

Re: Electric Bullet (pipe dream/possible winter project)

Posted: Fri Aug 19, 2022 9:53 am
by Duke of Wybourne.
stinkwheel wrote:
Wed Aug 17, 2022 11:06 am


There again, you're looking at that much for a half decent electric bicycle which can only do 15mph with a 30 miles range that needs to be pedalled.

Be interested in comments, questions and pitfalls.
From my own point of view and circumstances, I went the electric bike route. Depending on your level of fitness, this can greatly increase your battery range. I regularly get in the region of 90 - 110 miles between charges. Once you get past 15.5 mph, the power cuts out, so as my average speed is around 18mph, I'm only using power when I drop below 15.5 mph, which is usually when climbing. Also selecting the best power mode for economy helps a lot as well. Before anyone starts whining, I appreciate that not everyone is able to power themselves and sustain these speeds. Secondly, where I live most of the urban areas are 20 mph, so the speed is not much of a problem. And finally, although it is totally illegal, and I wouldn't condone such a thing, it's easy to get most decent ebikes up to around 28mph, and if you get a pre 2016 bike, which will probably be requiring a new battery, they were still legal to use with a hand throttle. Best to check up on that one though. My ebike is used solely as the family shopping trolley, and it serves its purpose extremely well.

It's also worth mentioning that as I live in an area where the council are pro cycling, you can get through traffic on a bicycle, and on to your destination much quicker on the cycle only routes, than you would ever do on any motorcycle.