Motobecane Popping

When i start up my motobecane, it pops 2 or 3 times then starts up fine and runs trouble free. Why is it popping?

Maybe ignition?

Re: Motobecane Popping

what do you mean by popping,be more specific

Re: Motobecane Popping

Like...

...rumblerumbleKindaLoudPoprumblerumble_LOUDPOP_rumble _LOUDPOP_rummblerumble....

Re: Motobecane Popping

Iiiiiiiii Died /

back fire pops?

Re: Motobecane Popping

Leon Swarmer /

my guess is timing

Leon

Re: Motobecane Popping

Jason Luther /

yeah, or bad plug. missfiring and letting unburned gas get into the exhaust and then backfiring.-jason

Re: Motobecane Popping

David Williams /

Is the pop like a squeaky pop? I had that problem and it was just my head gasket leaking. I removed the head gasket and i'm running without one now. Problem solved.

Re: Motobecane Popping

Mike McScoutington /

if your gasket is blown you can make one out of a cereal box. when i tore my engine apart i found my gasket was blown so i made one, and low and behold it works great.

Re: Motobecane Popping

About using a cereal box. that is fine for a base gasket. but I would not try it for a head gasket. It gets too hot up there.

If it pops for a little bit, then runs fine, I do not think the problem is not serious enough to pull the engine apart?

Re: Motobecane Popping

i thought that had something to do with the decompression lever? are am I wrong dan,

Re: Motobecane Popping

Yeah, i'm guessing timing, becasue spark plug is good and i had my head off the other day and the gasket is fine.

Now, how do you adjust timing on a motobecane 50v?

Re: Motobecane Popping

If you are using the decompression valve to help you start, it is completely expected to get a few pops.

Do a search for setting the timing on motobecanes, there are a few good old threads on the subject. If it is running fine though, I would not do it.

Re: Motobecane Popping

Matthew Westberg /

Agreed, you might just be holding down the decompression too long. When mine runs fine, you'll get a back fire or two if you hold down the decompression too long at startup.

Re: Motobecane Popping

Allthough it sounds like a backfire, it is really a forward fire. It just sounds like a backfire coming out of the decompression valve.

Re: Motobecane Popping

man i had a feeling it was the decompression lever, my motobecane knowledge is slowly growing

Re: Motobecane Popping

Decompression lever is the most likely choice. Release as soon as the engine starts to turn and you hear the fump-fump-fump of the exhaust, or when your lights come on. The bike isn't supossed to run with the decomp lever pulled.

Re: Motobecane Popping

If you remove the head gasket do you need to adjust the timing any different than stock?

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