motor swap?

hello everyone, im a going to say this right off the bat... im a total newbie to this so please take it easy thanks.

to start off i have gotten a moped from my dad wich he got from his grandfather and its been sitting in a garage for over 20 years, so it doesnt start. i do not know whats wrong with it but my dad said it is probably electical and it didnt start when he put it away.

my question is with it being a motobecane, 1977 (i think), and having a pedal motor, is it possible to take the whole motor and pedals, everything off of it and put maybe like an 80cc dirtbike motor on it?

my second question is, if this is possible how would i go about this. im figuring ill have to put new brakes and a clutch on it as well??

the gas tank is part of the frame and im not sure how the brake system works, like i said im new to this, im more than happy to sit and read up on how to do this, if its possible. so let me know what you think is it possible and how would i go about it, or is it a tougher job than it seems to me and i should just leave it alone???

thanks for reading :)

Re: motor swap?

♣Slew Foot♣ /

it would be a hell of alot easier and cheaper to fix it. then mod it into a monstrousity.

first is the right way, then the quick way.

also the fuel system needs going over start at the tank, petcock, then carb.

if it is orange or yellow it is an older one and 6v.

the brake light circuits have to work for it to start

the zenor diode is the weakest link, then the condensor.


Re: motor swap?

you want to hack on this ped?

put the tools down and back away before someone gets hurt.

go buy a amf roadmaster, all pro, or something to hack up.

why not impossible to do the mod you're suggesting, i'll put $$ it never happens.

did you run this idea past your dad or grandfather before posting here?

basically this site is for the restoration and promotion of vintage mopeds like the one you inherited.

you WILL be flamed, abused, and basically driven away for what we consider sacrilege.

IF you are still seriously considering this motor swap idea, may i suggest this site?


you will not be disappointed

Re: motor swap?

Jimbo Grand Daddy /

Do not even consider the sacrilege of putting a different motor on that bike. There is a wiki section on this site which has several repair tutorials to fix that baby up right. I have two unmolested Motobecanes and they are quite finicky bikes, but when you treat them right, they are quite rewarding.

Re: motor swap?

sell the ped and go buy a dirtbike!

Re: motor swap?

80cc dirtbike engine = 50mph after shifting through gears.

74cc AV7 = 60-70mph ONE GEAR !!!!!

Like Glenn said you will never do it because if you have to ask then you don't have the skill.

Replace the fucking condenser and ride that shit. You have a AV7 motor and Parts can be found here TREATS

Re: motor swap?

Mopeds don't go fast enough ? Yeah this is a Motobecane.


Re: motor swap?

Re: motor swap?

charles benda /

hell ill give you $200!!!!!!!!!

and all your troubles will be over.

my moby sat for 33 years and a new condenser away i went.

Re: motor swap?

ok ok you guys are kinda harsh now it looks nice but after i took the motor apart and looked inside the gas tank (wich had gas sittting in it for years and years) its not very pretty it all rusted on the inside and so it the motor there isnt even a spak, nothing it does nothing this is why i thought of the motor swap idea apparently ive gone to the wrong site to ask such a question though... and i cant sell it sorry

Re: motor swap?

You need a condenser to get spark or you can buy a cheap CDI ignition for about $70 at You can clean the rust out with acid, or vinager + salt, or reverse electrolysis. Your Moby is probably in better shape than a lot of the bikes on here were before we got them and put in a little work. Just so you know, you have the Cadillac of all mopeds.

Hey its your bike. Go ahead and slap a dirt bike motor on it and when your frame cracks and drops you on your ass at speed you will begin to wonder if it was a good idea.

I will buy your AV7 motor with carb and pipe if you do the motor swap. (edited)

Re: motor swap?

its gonna be cheaper and easier to just fix what you have. not to mention its a moped right now, once you slap a dirtbike motor on it- its a motorcycle; tax, tag, title, and insurance.

Re: motor swap?

Zeke Rigg /

wait there is rust in the tank how bad? if it is bad watch out for your frame snapping in half ps mounting the wrong motor is just as hard as getting your other one to run right

Re: motor swap?

Getting the Movy AV7 to shoot a spark will cost you $10 for a new condenser (if you are getting ripped off, less if you look for one) and perhaps 1/2 hour of work - maybe 1 hour if the Novi nut is being a bitch. Disconnect the old condenser, wire the new one into the grey wire going to the external coil. Check the bonding strap is in goodly shape. Pedal BOOM snappy bright blue spark.

You need a goodly solid frame for either rescuing the bike or converting it into what ever abomination is in your mind... monocoque frames so if the tank rusts out the bike will fold like a taco. Any rust at all beyond slight surface rust would be a good indication you need a upper stress bar.

Transplanting an engine into her is much more work then getting one back on the road - much much more work. Unless you want something that runs like shit and looks equally shitty. Very doable if you take the time and have the facilities to engineer and make the engine mounts. Here is my Moby with the Sachs 50-s with a 6 speed. Bitch of a job to get it together but there you are it is doable...

Equally doable is to transplant a pocket bike/asian honda knockoff 3 or 4 speed auto onto a Moby... Easier job but not finished yet because I started at the beginning of spring and too many other things came along - like good riding weather - so she will be done in early winter. Also cannibalized the forks from the pocket bike...

Re: motor swap?

If you want to swap something...

Trac Clipper + Lifan 125cc + upper brace + beefy brakes/susp = Nastyyy!

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