1980 Motobecane runs like dream until.....restart

I've got a 1980 moby motobecane which i've brought back to life, or at least occasionally. She will start but only after a few hours of sitting. I can start her up, and ride ride ride get great speed, the idle is awsome, then i get to my destination and give her the old kill switch. I'll walk away for 10-15 min and get on and i can pedal till i die and she wont start. Its kind of annoying, but when she does start it's a dream.

My other question is, i haven't cleaned the points yet, which "fred" recommeded, although i'm quite puzzeled how to the cover of the flywheel off to get to the points and magneto and what not, if there are any moby lovers out there maybe they could give me the secret to getting the cover off, so far i'm having no luck... thanks mopeders

brandon

Re: 1980 Motobecane runs like dream until.....rest

that's a tough one.. the bike runs well.. idles fine. Can't say it's a carburation problem.. doesn't sound like it's overheating and needs to cool down to re-start. I can't think of an electrical problem that would exhibit itself only on hot restarts, but anything is possible with electrical components.. hmm..

Do you always use the choke to restart it, regardless of if the engine is warm or cold?

and explain what you mean by _She will start but only after a few hours of sitting_

Does that refer to a hot engine? Does it start up without any problem when the engine is cold?

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Well on a cold start i'll just start peddeling a little down my hill and give a little gas and she starts up. i dont think i use the choke, may-be a tad, but some throttle usually works. i guess it doesnt start up like a dream but it starts after a few rotations of the pedals. After a few hours of sitting in my drive way i'll get on peddal a little down my hill and all is good. THe engine has cooled down.

If the engine is over heating wouldnt that effect the ride and cause me to over heat in transit? cause she runs like a beauty. an electrical issue could be it, might be the actual on/off switch / horn or the coil or geez lol

coil seems fine, i get a nice blue spark in the dark

the magneto i havnt even touched, i guess i should invest in a clutch puller / ignition puller from mopedwarehouse.com

i'm open to any ideas

Re: 1980 Motobecane runs like dream until.....rest

yeah.. engine overheating will be noticable.. loss in acceleration and in top speed... probably cause the engine to die at stop lights, etc.

i dunno.. What happens when a hot bike sits? It cools down. One othe thing that often happens is a carb can leak fuel into the crankcase. Restarting it fouls the plug.

BUT if that bike starts fine when left for a few hours, a flooded crankcase can be ruled out.

Get that thing good and hot so it won't restart. Then do some testing..

like pull the plug and examine the tip.. Ground the plug and estimate the spark's strength.

Also, spray some Starter Fluid into the carburetor when its hot and refuses to start. If it starts, this indicates a lack of fuel delivery.

Re: 1980 Motobecane runs like dream until.....rest

Matthew Westberg /

I had the same problem with the magneto cover until just recently.

What I do to get the Magneto cover off is use the "Inertia Trick".

First of all, get a plain old 3/8ths socket wrench (the most common size) and a hammer. The square head on a 3/8ths wrench fits quite well into the sqare hole, making a more than acceptable substitute. Now, look at the magneto cover, you can see that there's two peices: the main cover and the small central plate (with the square hole). Use a utility knife to make a small scratch mark that runs across the edge where they overlap (this is so you can see if you're making progress and let's you know how close you are to the original position when you put the cover back on).

Now you want to insert your socket wrench into the square hole. KEEP IN MIND: This is a _reverse_ thread and will loosen by turning clockwise not the otehr way around! What you want to do is use the hammer to whack the end of the wrench handle quite hard. Due to inertia, the central plate will (in most cases)be knocked loose a bit (you should see the line you marked split as the two pieces of the cover separate)keep hitting the wrench as needed, but after a few whacks you should be able to simply unscrew the centre plate by hand and take the main cover off (it contains the large magneto magnets, so don't worry about it sticking, just pull away).

When replacing the magneto cover, besure you line up the cover's two small bumps (inside the main cover plate with the magnets) on the two small dents on the hub of the cam.

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Well i just looked at the plug, and it's been say almost 3 hours since it ran last, and it's dry as a bone. She still wont start. How should i estimate the spark strength, when i give her a pedal the spark is blue. im wondering if the magneto isnt shot, with the points, cause i havnt cleaned or messed with them. im not willing to give in and let an expert fix it !!

Re: 1980 Motobecane runs like dream until.....rest

See Ya Moped Army /

If you a nice fat blue spark, the magneto is fine. I would still clean and check the gap on the points. I would also check timing.

Rather than use a hammer, take a piece of pipe and slip it over the end of the socket wrench. You'll get much better leverage using a pipe. It should brake free with no problem unless it is frozen solid in place.

Re: 1980 Motobecane runs like dream until.....rest

tried some starter fluid?

I suggest this since the plug is bone dry AND because the fuel delivery circuit in the carburetor that starts the biks is different than the circuit that provides fuel during normal running.

Re: 1980 Motobecane runs like dream until.....rest

Replace the condensor. Many people recommended it to me when I was having similar problems. I messed my bikes up a little (ok a lot) trying to get the damn rotor caps off, It took EXTREME presure to get mine off, and I hurt my babies (search for a post of mine from last month). On one bike It seems like it just tweaked the cam a little bit ( A complete timing job should fix this) on the other bike, the big presure created by forcefully twisting, and banging on the cap created some play in either the cylinder, or the rod. the bike runs, but makes a hell of a lot of noise. when I turn the cylinder by hand, I can hear a light clank somewhere in the rotation. when I get past 10mph, the clank gets really loud. So my advice to you, read my post about rotor cap, and get a proper piston stop.

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Yep gave the starter fluid a try, love that stuff when it works.

Thanks for the crank removal ideas, i'm gonna try that later on and see if cleaning the points doesnt fix my "restarting" problems.

Its almost like my ignition doesnt want to work kinda like a car, then it has it's moments and wants to start. weird.

brandon

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

so buying the removal tool would be wise? i can handel that, yeah so whats a condesner, lol i'm pretty good with this stuff but i call alot of the parts on the moped a "thingie" thanks lol

brandon

Re: 1980 Motobecane runs like dream until.....rest

Matthew Westberg /

HAHA!

If you know where to buy a proper Motobecane stroke limiter, I'd like to know! sadly, while this would be a useful tool, it's not exactly the easiest thing to find.

Sorry, we make do with what we have. I use a hammer over a pipe becuase the increased leverage of the pipe is more smooth but it's easier to possiby damage the piston or camshaft that way. The hammer hits need not be huge, mere ly enough to loosen the cover plate. If the magneto cover is jammed on far too tight, other things like penetrating oil, heat or WD40 should be tried.

I learned the Inertia Trick from a career engineer who used to work on mopeds when he was younger, so I think I'll stick with it.

Re: 1980 Motobecane runs like dream until.....rest

Matthew Westberg /

By the way, what on earth do you mean by replacing the Condenser? I didn't think the variator engines had one?

Re: 1980 Motobecane runs like dream until.....rest

a condenser is two separated metal plates. Positive static electricity is on one plate and negative on the other. When charged up, and if the plates touch, electrical energy is released. These condensers are used to assist the ignition coil when the coil produces a spark at the spark plug.

Condensers used in an ignition system are small metal cans. Thin sheets of metal are used for plates and are wrapped around in a spiral, separated by a 'dielectric' paper material and stuffed into the small can, about 2 inches long. One wire, connected to one plate comes out of the can. The other plate is attached to the can's metal body.

A variator is an "infinitely" variable pulley.. the sides of the variator-pulley can close and open, making the pulley larger and smaller. Variators provide a convenient way to "shift gears" on vehicles that use drive belts.

The two devices are unrelated.

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Well thanks for the info on the condensers. How much would a new condesnser cost me? any also any ideas on a location to find one? thanks

brandon

Re: 1980 Motobecane runs like dream until.....rest

Matthew Westberg /

Oh you mean the little capacitor screwed on the front of the engine? Is that what you're talking about?

Re: 1980 Motobecane runs like dream until.....rest

It's also important to note that the bolt on the magneto is REVERSE threaded. Many-a-bolts have been stripped due to the left loosey righty tighty rule.

I had a non running Traveller. Opened up the magneto and all of my issues were coming from there.

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

thanks everyone for the help, i didnt get to test all of the ideas thrown around on this post cause i'll be at work a for a few days but when i get to my moped im gonna work on some of your ideas.

brandon

Re: 1980 Motobecane runs like dream until.....rest

the man named MOPEDLAR who contributed to this forum sold me a NOS condensor, try shooting him an email.

Re: 1980 Motobecane runs like dream until.....rest

i had this same problem with an old columbia. i found that if i shut the gas off everytime i stopped( even if for only 10 minutes) the bike would start fine

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Should i cut the engine first with the kill switch then turn off the fuel or turn off the fuel and let the engine run dry?

Re: 1980 Motobecane runs like dream until.....rest

boomhaur

it sounds like your coil is bad. after the coil heats up it shorts itself out and then you can*t start it.

change out your coil with a known good one from another ped

and see what happens

leo

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

im starting to think so too, i went for a cold start and she didnt even try last nite. and she has been getting less and less frequent with a cold start.

anyone have an idea for a coil...besides lol mopedjunkyard? ill try the buy/sell forum

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Ok, so it seems the coil is fine the spark is fine, but the problem we've noticed is when i pedal i the clutch isnt spinning the flywheel so the engine isnt turning. yes the engine is in turning condition i've had it running

When i remove the spark plug and there the compression is less i can pedal easily and the flywheel and clutch kicks in and catches turning the magneto and engine.

So looks like my clutch isnt engaging when i pedal, in fact it doesnt, i need some help to figure out how to fix that, and also how to get the dumb cover off with out a clutch puller. thanks

brandon

the magneto cover trick worked perfectly thanks ! !

Re: 1980 Motobecane runs like dream until.....rest

pull the decompression lever for a second when you try to start it, that will make the engine spin easily. Sounds like your belt may be loose as well I replaced mine with a 4L32 from the auto parts store, it works well.

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

im pretty new with this moped terminology so what is a decompression lever and what does it look like? thanks i'll check the belt, it looks new the previous owner must have replaced it. thanks

brandon

Re: 1980 Motobecane runs like dream until.....rest

Brandon Henry /

Thanks to the forum for all your help, she runs again, dumb belt wasnt turning the flywheel or crank which inturn didnt turn the magneto.

Now that i'm back from ridding i've shut her down turned off the gas, now will it start???? i'll keep you informed.

brandon

Re: 1980 Motobecane runs like dream until.....rest

decompression lever is your right hand thumb lever, use it to shut off your moped. it also helps get the engine spinning when starting.

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