1982 MB-5 HubmonsterHE build (pics 5/19)

[hillzofvalp]

So here's my first post over here in motorcycle/scooter land, though there is a fine line between high performance 29ers and pedal equipped mopeds.

Recently I became infatuated with retro sport mopeds. One in particular that I will likely never find is the Jawa ultra sport.

I envision lacing the cromotor I have into a 16-17" wheel with racing tires... Running 26-28S a123 and having a blast... Getting it registered as a moped cause no one will think its that powerful... Lol... You get my drift.

I would expect it would be more practical and comfortable. With 2kWh it might even make 60 miles at say 30mph (idk, but I do see it's aerodynamics helping considerably).

This to me would be the coolest ebike ever. But is it worth pursuing? They seem pretty cheap.. But I wonder what the dropout slot width is and whether they would need beefing up. Also wondering if lacing up moped wheels is just as trivial as doing a bicycle wheel... Or whether I need to have a professional do it.

http://www.mopedarmy.com/forums/read.ph ... 81,2776481

[Scoot440]

It sounds like an awesome project. I recently built a hub-motored Solex moped for a friend and have found the ped components to be much more forgiving and capable of handling the weight and power than most bicycle parts. Also, the availability of cheap parts for mopeds is pretty astonishing. The only real drawback I have found in the peds is the added weight.

[hillzofvalp]

This thing is only 112lbs stock!

[Jeremy Harris]

Interesting you're thinking of doing this, as I did spend an hour or two looking at fitting one of these big hubbies to my RD50 frame. It would have fitted OK, but would have needed spacers on the axle to fit the wider drop out width and getting a rear brake to work would have been tricky (unless I had disc brake caliper mounts welded to the swing arm). I also looked at getting the drum brake version of the same motor via Aliexpress, but didn't feel confident enough about the quoted specs.

[hillzofvalp]

What is the ball park rear spacing? The cromotor axle comes a bit on the wide side, at least from Jeremy wolf. Between 145 and 155mm, I can't remember. Who needs a rear brake when you have regen at 100V in a tiny wheel?

[Xanda2260]

What is the ball park rear spacing? The cromotor axle comes a bit on the wide side, at least from Jeremy wolf. Between 145 and 155mm, I can't remember. Who needs a rear brake when you have regen at 100V in a tiny wheel?

I'm guessing here, but a rear brake might be needed to get it registered/mot'd.

[johnrobholmes]

Building the wheel isn't so bad if you already know the basics. I have ridden three hub motored classic mopeds, it is an easy project. You will need to beef up the dropouts for the cromotor.

[Jeremy Harris]

What is the ball park rear spacing? The cromotor axle comes a bit on the wide side, at least from Jeremy wolf. Between 145 and 155mm, I can't remember. Who needs a rear brake when you have regen at 100V in a tiny wheel?

I'd need to go and double check, but seem to remember it was around 175 mm, so the spacers wouldn't have been that thick. The rear brake requirement is as already said, it would legally have to pass a roller test for brake efficiency here every year, as it's already registered as a small motorcycle/moped.

[hillzofvalp]

Building the wheel isn't so bad if you already know the basics. I have ridden three hub motored classic mopeds, it is an easy project. You will need to beef up the dropouts for the cromotor.

Sounds promising and inexpensivr. Do you have links or pictures?

[johnrobholmes]

I don't, except my Hybrid Hobbit which was front wheel drive, pics can be found on this forum. The other ones were just a friends builds and he doesn't get on the internet really.


Rear spacing on mopeds is generally between 155 and 175. One of them we did used a front 9c hub in the rear of the bike. It was a zip tied project!

[hillzofvalp]

My dream: a variation of the kawasaki AR80 or honda MB5:
imagine a cromotor on this bike! it would blend right in.







I would come close to the original weight. I weigh 200 lbs. I figured with short range pack installed and excess metal gutted out it would come in to system weight around 340 pounds.

Overall Length 74 in (1880mm)
Overall Width 27.8 in (705 mm)
Overall Height 40.4 in (1025mm)
Wheelbase 47.8 in (1215 mm)
Seat Height 29.5 in (750 mm)
Foot Peg Height 12.2 in (310 mm)
Ground Clearance 6.3 in (160 mm)
Dry Weight 174 lb (79 kg)
Curb Weight 198 lb (90 kg)

[mr.electric]

I helped a co worker convert a puch magnum with a cylite motor. It is true that the moped parts are ideal. Many of the woes of Ebikes are non issues on a moped. The moped is designed to go down the road at 25mph for years and years. The bicycle favors light weight over durability. I was surprised to see how the cheap moped shocks seemed to work better than high end bicycle suspension for street riding.
Sorry I don't have any pics now.

[hillzofvalp]

There is a magnum nearby for $1200
... Very clean. Too much money though for a. Moped.. I could get a nice 50cc motorcycle like above for that amount.. Upload pics! I'm interested

I have my eye on this one, but she's $1500 but recently restored:


is the cromotor going to able to power a bike this big?

[mr.electric]

With mopeds the look is very important. Most are a bit dorky. The engine trans unit from a complete moped could undoubtedly be sold to recoup some costs. Or to really save cash start with a dead moped that you buy for almost nothing and spend some time restoring it. A top tank conversion would be another option to save money and end up with something that looks cool.

[hillzofvalp]

My last post was actually having to do with lightweight bikes classified as motorcycles. Mopeds generally have pedals and weigh under 150 lbs. But yeah. I'm looking around.. talked to an enthusiast today who restored 6 of the MB-5s in his life, selling off his last one (green above). he gave me some contacts to maybe get a basket case.

If I bought the above green one for $1500, he said I would be able to get at least $250 for the rebuilt motor and pipe.

Do you guys think it would look weird with a mag wheel on the front and a spoked cromotor wheel on the back?

[veloman]

I really like the look of these small motorcycles. Looks like a ton of fun to ride. I wish I could rent an electric version of one of these for times when I want to go out with the lady. I agree that most mopeds just don't look very good. Vespa style scooters are okay though.

[johnrobholmes]

1200 is way too much for a magnum. Look around and you could find them for about $400 if it needs a paint job. Or you could get a Garelli or any other Puch or just about anything and install your own "top tank" to get the look you seem to like. Hacking up an mb5 would be a shame IMO, unless it is already missing the motor.

[Scoot440]

I am with John, you should be able to pick up a neat project for considerably less than the prices you are seeing. Check on mopedarmy.com to see if there is anything in your area. I even see a fair number of MB5s and AR80s there, but a top-tank General, Batavus, Tomos, or something similar should cost 1/3 to 1/2 of what you are looking at. I picked up a Voloci there recently for very little money.

[grindz145]

I just picked up a Puch Magnum myself, except I plan to go with a Perm132 motor. It may be better to go with a big old hubbie in the end, but I'll have more fun with the perm I think

[johnrobholmes]

Beef up the rear end on that Magnum before putting big power on it. They are scary flexy in the rear end.


How much you get that Veloci for Scoot? I was talking with that guy a while about it, but he was wanting too much for it IMO. I couldn't get him below $300 for a non running bike.

[Scoot440]

I paid $300 for it and was happy with that just because it is very good condition. All it needed (and still needs) is a battery pack and charger. Every time I build something similar, I end up sinking quite more than that into it.

[Scoot440]

Here's one that might fit the bill and leave lots of room in the budget for components:
http://www.mopedarmy.com/forums/read.ph ... sg-3117481

[hillzofvalp]

Yeah. I looked at those but I think they're too dorky.

I found a guy an hour away from me who has a lot of MB-5 parts. He offered me a frame for free for prototyping purposes (want to get pack done soon while I have access to welder), but he has everything I would need.. would cost less than $500 he said.

I'll check it out tomorrow and see if it's a good candidate!

You guys think I need torque arms for this sucker? he said that the axles were 10-11mm but he couldn't remember. Hope they're 10. SHould I beef these up anyways and add pinch for 10kW+ cromotor??

[grindz145]

Beef up the rear end on that Magnum before putting big power on it. They are scary flexy in the rear end.

Thanks for the recommendation JRH. I'm just in the planning stage.

Is it mostly the suspension that's flexy or the swingarm itself?

[hillzofvalp]

where is your magnum build thread? my brother is thinking of picking up a magnum to run stock..maybe I could convert it down the road