Starting PROBLEMS! ..don-ohio and other help!!

Dave Chudak /


I recently got a 1971 motobecane 50v and it seems as though that pedals turn but the engine doesn't..... the pedals are turning the bell housing of the clutch (via the v-belt pulley), but i dont think that it is moving anything in the engine. If this were the case, the magneto would not move, and that would explain why i am not getting any spark.

The mechanism to flip between pedaling, and kicking over the engine appears to work fine. I have it set to kick over, but there is no resistance at all when trying to kick start...

i undid the plug, and put a bolt in the hole and pedaled and the piston is not moving up and down... so obviously something is not working, and the pedals are not engaging the mechanics to start the engine....

please help... i want to fix her up soon and get it on the road........



Re: Starting PROBLEMS! ..don-ohio and other help!!

I'll go get the manual, but it sounds like the clutch weights might not be moving. The clutch can get rusty inside.I'm not too good on MBK variators,but I'll look in the shop manual....... don-ohio (:^)

I will try to open the clutch

Dave Chudak /

I will attempt to open the clutch tommorrow to see if its rusted to shit....

Exactly how does this work?

i understand that that when the engine is on the shoes come out and engage the bell housing... what i don't understand is how pedaling moves the clutch at all.. i wish i knew more about manufactured mopeds... ive only ever built my own out of bikes.....

i will spray with wd-40 so itll be loose enough to work on tommorrow...

thanks again don..


Re: I will try to open the clutch

Try not to get the WD-40 on the clutch pads if you can help it,Dave. I have to filter a bunch of water here at work now,but I'll check the manual soon. don-ohio (:^)

wd40 on the pads, no probs

Dave Chudak /

i sprayed lightly around the bell housing.. i will use break cleaner on the shoes (works ok to clean pads).. i have made the decision to take apart the bike entirely now.... i was thinking of just trying to see if i could get the motor running, but i think i may just do a complete dis-assembly and restoration.... the tank is built into the bike, and is rusted, so i need to redo the tank.. i will probably paint it, redo the springs in the forks a bit stiffer, completely rebuild the engine, and try to figure out this damn clutch...

do you recommend waiting to dismantle the entire bike, until i find out what this problem is, or should i go ahead and rip her apart... i wouldnt mind the experience of ripping it apart, i just have to make sure it will go together again, and hopefully work...

where do you work, filtering water? water filtration is an important job... i wish mopeds ran on water...

thanks for the help man


Re: wd40 on the pads, no probs

First,make sure the tank is solid. You don't want to have to replace the mainframe,do you? If the tank doesn't leak, get a shop manual from Chris at Mopedwarehouse. Best 20+ DOLLARS YOU'LL SPEND,BELIEVE ME.

Yeah,once you get a manual,you can tear it down completely, but if the steering head bearings and front forks are okay, I leave them alone usually. Pay attention to the pedal crank operation and the chains(special chains for MBKs). Buy tires last, because you gotta KNOW the bike will run right before you sink money in tires and tubes. Brakes,wheel bearings and races are very important.

You can buy a brand new variator from a guy here in Ohio if he still has them for I think about 60 bucks.

They are a good bike if restored correctly and they're tough. MBKs are sometimes hard to keep a condensor on, so always carry a spare,at least I would.

I just filter drinking water for my co-workers here....about thirty people,I guess in the immediate areas. The company won't provide drinking water that tastes good,so I filter it and wash out all the 5 gallon bottles. Just my way of pulling my weight here among so many good workers.

don-ohio (:^)

Re: wd40 on the pads, no probs

What're you doing up at this hour,Dave? It's almost 4AM ! LOL! don-ohio


Dave Chudak /

i dunno.. i usually can't sleep, until i figure things out... ive been looking at variator drawings, trying to figure out how i am going to get this damn this apart without the MBK tools

i think the front forks are ok... i shall check all bearings though..

i heard the condensors suck... ive heard of using a condensor from another type of ped, that is similar, but lasts longer... not sure though.. new to MBK's

so do the clutch shoes fly out when pedaling the ped, in order to engage the engine start.... if so will replacing those springs most likely remedy this problem?

the tank is flawless from the outside, and possibly rotting inside out.. but the inside doesnt look too horrible.. i filled her up, and i think its leaking from somewhere in the carb.. if i do a strip down, i will de-rust the tank, and reseal it with kreem or somethin... this will remedy any leaks hopefully...

i honestly have no frigging clue what i am doing, so i think i will just start tearing the thing to pieces,... i usually learn best that way.. as you said... i should get the manual.. is it the same one as on the MRA site?



Re: hehe

Yeah.....I know the feeling about being restless until perfecting something. I have been like that in my younger days....maybe up `til I was 40 years old. After that I started being less concerned,because time moves so fast when you get older. You aren't as concerned or impatient, but of course, you usually get less done too.LOL!

I really would like to make the Lake Erie Loop run. Actually I would like to ride up there on the `ped too, but that is probably 450 extra miles round trip or more.

I guess you could look at that manual. But I like ordering mine from Mopedwarehouse. They're always neat. don-ohio (:^)

i will order from MWH tommorrow..

Dave Chudak /

i will definetly grab the manual... and i will start stripping the bike down photographing my every move, in hopes that i might save some poor sucker time, somewhere in the future... i think i picture documentary of a motobecane 50v could be usefull...

well.. maybe we can all meet up in buffalo if my gang gets together and makes the commitment.... that would be cool, because one of my friends that i go to school with here in guelph, is from buffalo, so i could crash around there... awesome! hehe....

plus buffalo would only be 300+ km round trip... so it wouldnt be terrible.. my ass would definetly feel that trip on a bike seat though.. i may need seat post shocks, in addition to some front rock shox forks....

Re: i will order from MWH tommorrow..

yeah...the Sebring's suspension is great. The seta has a dense foam which doesn't let you `hit bottom',literally.Ha! I run bigger tires,too, and they ride even better.

If I were you,I'd get that MBK ready and ride it. Is it the kind with the big cushy,long seat for 2 people? I owned a nice Moby once,but I'm glad I sold it. don

its a long seater but the seats missing..

Dave Chudak /

i will be constructing a new seat, in place of the missing seat.. i will be making it relatively the same, except with a duck tail at the back, which lips up just a little bit like a seat back.. but only about 2 inches high... itll look nice...

i did a motorbike seat for some buddies with a new staple gun and some black vinyl... pretty easy to do... just need to stretch out the vinyl real good..


Re: its a long seater but the seats missing..

How you gonna get the foam dense enough? That used to always be a problem with aftermarket seats. I'm sure Handy Bikes has that seat brand new. Maybe ChrisMWH has one too? He'll deal with you probably. Well.......time to put that coffee on! Good Night,Dave! don-ohio (:^)

Re: its a long seater but the seats missing..

remember, when you take that 14mm nut and the grease fitting off, and remove the snap rings and washers(spacers)., to disassemble the variator,you'll have to unscrew the 35mm nut the opposite way from normal `cause it's Left-hand threads. don-ohio (:^)

Taking off the grease titty

Dave Chudak /

how do you get the grease tit out... its got nothing to grab on to... the sides are rounded.... any suggestions?


DON - Pictures of my variator

Dave Chudak /

here is a picture of the variator.. im pretty sure a cover is missing...


one or two speed...

Dave Chudak /

im not too sure, but i think this is only a one speed... which is strange because the motor pivots, and is sprung.... it appears to only have a pully, and not a variator.. but i have not taken it off the bike yet, so i am not sure...

Re: one or two speed...

If the VIN tag says 50V,the `V' stands for variator. `Course someone coulda' swapped engines. I dunno about the grease fitting,except needle nosed vice grips might work?

Sorry..I can't see any pics on this forum from work here. They give me a surf-control block every time I try to view them. don-ohio (:^)

Motobecane Mobylette N50

Dave Chudak /

I was told by someone that the N50 is the same as the 50v, except that the N50 was made for canadian sale.

It says "type N50"

it has a pivoting motor... and is a 49 odd cc motor.. i think 49.9cc....

the headlight is white, and square...

anything you can find out about what an n50 is would be sweet....

thanks don

Re: Motobecane Mobylette N50

When you have a variator type engine,you can see the pulley narrow and make a bigger ratio or widen and make a smaller ratio as you rev the engine.

Take it apart and if there is a moveable pulley face,it must be a variator. Again,though, I'm no expert on MBKs. I like the Sebrings and Tomos' and Puchs and other European bikes better for working on. don-ohio (:^)

Re: Motobecane Mobylette N50

Dave Chudak /

I realize how a variator works, i just have not got around to taking apart the clutch, so i cannot see if there is a variator yet... from what i can see there isnt... there is a low-sided pully that the belt goes to.... and i have not had the engine running, so i cannot tell through just revving the bike on the stand...

thanks though don... i appreciate the help so far... i shall be tearing it apart with authority soon.... the only thing i am afraid of is the wiring, but im sure thats all pretty basic connections that can be tested with voltmeters ...

i will let you know when i start gutting it..... the first project will be taking all the parts off of the frame, and stripping the entire bike to bare metal... then fixing the gas tank.... then repainting the whole thing....

then the clutch, and engine, and magneto.... then seat, shocks, and lights... then i should be ready to roll...

Re: Motobecane Mobylette N50

Sounds like a plan! Keep us posted,Man! don

will do don

Dave Chudak /

i will let you know as soon as i do anything major... i will post pics of all the work i do on my webpage.....

talk soon

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