Motobecane 50V Won't start. Clutch, or Muffler?

Ok, I just got this A speed 50v. 1980. It looks like it is ready to go however, I just am not sure what exactly is wrong with it.

When you pull in the decompression, the magneto/right side of motor, will spin but not enough to make that turnover noise. Plugged muffler??? Dont really have a clue. Pulled the clutch and cleaned it out best I could, and looked like everything should be working.

Anbody know how fast an A speed 50v would go???

Also, I got two 51v models. How rare are they and are they worth a lot? I'm pretty sure they're rare. Never seen one before and I have 7 mopeds.

Thanks

Jim

Re: Motobecane 50V Won't start. Clutch, or Muffler

🇮🇹💦 Of the Loin /

it sounds like you might just need a new belt actually. 4L320 or 17321, hardware store or auto store your choice.

the A speeds are 30mph versions, and it will go about 30, although they tend to just keep picking up speeds (i can hit about 35 or so on a flat)

the 51v's were never really introduced in the states. The engines are reed valve unlike the piston ported mobys which are pretty standard.

Basically the 51v's are desirable because all the kits for mobys are reed valve kits, and so the 51v motor is perfect for it.

Speaking of which I would love to buy one of those 51v engines, intake and all off you

Re: Motobecane 50V Won't start. Clutch, or Muffler

Those 51v's are pretty cool, They won't fetch insane prices but if their nice and you find someone that wants one I'm sure you can get a fair price.

Re: Motobecane 50V Won't start. Clutch, or Muffler

yea they look really neat. Both of them are 1981 models. A belt...? didn't think of that but I dont think thats it because the belt on it seems pretty good. oooo Thats cool how the 51 motors can be kitted. Well I bought 3 and my dad is going to take 2 of them and I'll only get one even though I bought them so I mean, I'm still thinking about which to take. The 51v need a considerable amount of more work. The 50v is almost totally complete. I think because I have a batavus project and a puch maxi project I'm going to take the easy way and go for the 50v. We have had some verrrry fast motobecanes. I new about the speed classes but the thought never entered my mind that the ones we had were of different class. It explaines why our old rusty one flew by the mint one. It was a higher class!

One of the 51v's is a C class and the other is a B so I think I'm getting an ok deal.

After all, we drove a good 150 miles or so to get them. Yea we have relatives in the area but had no intention of going proir to this deal. I'm really pumped to get that A speed on the road. According to my father we've never had one and that old rust one was a real beast! Whoooo!

Ok, thanks for all your help guys.

My dad is a mechanic but the more brains on this the easier it will be to get it running. think we wil want to hang on to the 51v's but I think that once I get this 50v all good and running and a reall sweet moped, I'll sell it in the spring. The nicest thing about the 51v's is the seat. It's easily big enough for 2. I mean, with room to spare. These motobecanes even had racks and mint clean tanks. O Yea!!!

Any other thoughts on my issues be sure to share!

Thanks For Your Help!

Jim

Re: Motobecane 50V Won't start. Clutch, or Muffler

Check your drive belt...does the left hand clutch part spin when you pedal? Check kill swithc..these sometimes stick...check for spark also. Good luck!

Re: Motobecane 50V Won't start. Clutch, or Muffler

well I can't really check for spark cause the magneto doesn't move very fast when ya pull in the decompression. Not the kill switch. there is definately some kind of clutch issue with this one here...

Re: Motobecane 50V Won't start. Clutch, or Muffler

🇮🇹💦 Of the Loin /

what seems like a clutch issue is usually just the belt. Try a new belt, it will only set you back about 5 bucks

Re: Motobecane 50V Won't start. Clutch, or Muffler

Jim, you can check for spark just by turning the flywheel/magneto by hand... pull the plug, hold it against the engine block, and give the flywheel a (clockwise) spin. With the plug hole wide open, there will be no compression so it should be relatively easy to turn. If it's hard to turn, you may have found your problem-- rusted crank or something like that.

Re: Motobecane 50V Won't start. Clutch, or Muffler

yea ok I'll check the belt today. I have time. And it does have spark thanks so much guys!

Jim

Re: Motobecane 50V Won't start. Clutch, or Muffler

abd to everyone looking to buy a motor, I think we'll hang onto them for now

Re: Motobecane 50V Won't start. Clutch, or Muffler

🇮🇹💦 Of the Loin /

blast it all!!

Re: Motobecane 50V Won't start. Clutch, or Muffler

LAME

you better build a sick moby if ur gonna hang on to them. 51 engines should not just be sitting around in the garage.

Re: Motobecane 50V Won't start. Clutch, or Muffler

sorry abou that. Was on my dads account accidentally but no those 51v motors will be puit to good use.Sorry to all who wanted one but not 4 sale.

It isn't the belt. Thats still in good condition. Must be something else

Re: Motobecane 50V Won't start. Clutch, or Muffler

replace the belt you'll be surprized, get the 17321 from an autoparts store

Re: Motobecane 50V Won't start. Clutch, or Muffler

well I'll replace it but we have had lots of motobecanes with no replaced belts and never had this issue

Re: Motobecane 50V Won't start. Clutch, or Muffler

i could be wrong but your description points right to the belt, also make sure the decompress is actually working.

lemmy know how it goes good luck.

Re: Motobecane 50V Won't start. Clutch, or Muffler

🇮🇹💦 Of the Loin /

the belts do get loose after years, even though they may look fine. Your description is exactly what happened to mine. I bought a new belt and blam starts right up

Re: Motobecane 50V Won't start. Clutch, or Muffler

ok. I thiunk we have 5 moby's maybe 6 so I'll go give it a try. got so many parts I know we have belts here.

Thanks

Jim

Re: Motobecane 50V Won't start. Clutch, or Muffler

Um, I just read this thread a little closer, and I have to burst some bubbles here. The 51v's available in the states in 1981 do not have the AV10 engine. That engine was never imported by Motobecane. They're just fast-model piston ported AV7's, like the 50v.

Re: Motobecane 50V Won't start. Clutch, or Muffler

huh. and it isnt the belt. pulled the clutch apart and something aint right.

Re: Motobecane 50V Won't start. Clutch, or Muffler

ok I listened to my dad and didn't change the belt. Went and listened to yall and youy were right. Fastest motobecane I've ever ridden! Thing may do 30+! Not sure couse the speedometer was bent wayyyyyyy past 30!

Re: Motobecane 50V Won't start. Clutch, or Muffler

🇮🇹💦 Of the Loin /

buy yourself the 14/14 dellorto replica from davesmotors it will go even faster

Re: Motobecane 50V Won't start. Clutch, or Muffler

yea? Like how much faster? A biturbo adds like 5 miles per hour, what would a better carb do?

Re: Motobecane 50V Won't start. Clutch, or Muffler

same, do you have a biturbo on a moby? I'd like to see a pic if so.

Re: Motobecane 50V Won't start. Clutch, or Muffler

no but I could if I wanted to. right? doesn't seem like it would be a huge deal. With a little tweaking the thing would really fly I bet. Well it goes about 32 as is and I think I'm going to sell it. Already have someone semi interested

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