The piece of junk still won't run!!!! Arrrrrrrgggg

Ray Sanders /
Jul 06, 2001 03:45PM

Okay, all.....

My motobecane died on me two weeks ago. Just started sputtering like it was out of gas, lo and behold it was about the exact opposite. From what everyone I have talked says it's a bad carb float (gas would just pour out the throttle body).

So.....I have replaced the following:

Spark Plug

Choke Cable (It needed it)

Carb Float

New gas (.95 gal. 91 Octane Ethanol Blend / 3 oz synthetic oil)

The bike acts like it WANTS to catch, but all it does it putter along while I'm pedaling it, or pushing it along with my feet. (very tiring, yet somewhat easier than pedaling)

While the engine is sort of running you can hear it "pop" once every few seconds like it's about to catch.

I've pulled the plug and it seems like the bike is getting fuel to the cylinder.

This is the same problem I had before I replaced the carb float, but now the fuel isn't just pouring up and out of the jet/throttle body

I have no idea what to do..... and the one thing that is running in the back of my head

(cutting torch and/or sawsall) would not be pleasant nor appreciated by those who appreciate these monstrosities.

I'm not trying to bad mouth mopeds in general mind you, just my pile of two-wheeled excrement.

Any ideas? Please? I'm very frustrated and I want to either get this thing running, or rid myself of it.

Thanks in advance!

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Re: The piece of junk still won't run!!!! Arrrrrrr

Ron Brown /
Jul 06, 2001 06:38PM

Ray,

I posted the following for someone with a brand other than Motobecane. I have edited it a bit to be more specific to a Moby.

If you have a vom, check the ignition components as follows:

Remove the flywheel from the left side of the ped. Use a 3/8" socket driver and an impact wrench. THIS IS A LEFT HAND THREAD!

Disconect the wires from the points. One of these wires goes to the magneto ignition power coil. You should read a low resistance to ground on this wire, 1-2 ohms.

Another wire goes to the condensor, mounted on the back of the magneto plate next to the cylinder base, read this to ground on RXMAX, that is your highest resistance range, the needle should kick, then settle down to infinity. Reverse the vom leads, same thing should happen.

Another wire goes to the ignition coil primary, this connection is also connected to the kill switch. Disconnect the kill switch wire only from the ignition coil, the wire to the coil should read 1-2 ohms to ground.

From the wire to the kill switch, to ground, you should read infinity with the switch in "run" and 0 ohms with the switch in "stop".

Connect the vom from ground to the wire terminal on the points and make sure they are 0 ohms when closed and infinity when open. This seems dumb, but sometimes points that look clean do not connect.

Re-attach all of the wires to the points. Disconnect the wire from the points at the ignition coil. Measure this with the vom, it should read near 0 ohms. If your meter is sensitive enough, you should see a slight deflection of the pointer as the points open and close.

With the vom still attached and set to about 12v DC range, spin the motor by hand. You should see some deflection of the meter needle.

Pull your plug (spark, that is) and make sure the piston is at or very near the top of it's stroke when the points open. (Actual Moby is 2mm btdc)

Re-connect the coil wire. Measure from the plug cap to ground, you should read 5-15k ohms. If this is infinity, unscrew the plug cap from the wire and read through it. This should be 5-15k ohms, if it is open, replace it, if greater than 15k ohms, it may still work, but replace it with a paper clip for test starting then re-install it after you get the ped running.

Read from the end of the plug wire to ground through the coil, you should see 1-5k ohms. If this is infinity, the coil is bad.

Lastly, using the ohmsX1 scale, verify that all of the grounds really are.

None of these tests are guaranteed to indicate a problem, especially where you read coil resistances and they seem ok. Substitution is the best test here.

Ron

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Fixed!!!!!!!

Ray Sanders /
Jul 07, 2001 01:45AM

Ron, thanks for the advice...

Just after posting I called Mark over at Marks' Mopeds. (www.marksmopeds.com) He had suggested basically the same thing, except this is the funny thing. I went to have a buddy of mine hold the plug against the cylinder head while I pedaled, and he noticed the coil wire to the spark plug boot was very loose where it met the boot/metal sleeve. Spark was intermittent due to a bad plug wire connection to the plug boot. Cutting the boot/sleeve and exposing some copper wire, then wrapping the copper wire around the top of the spark plug confirmed the problem as the bike proceeded to start after pedaling for aout 3 feet. I would have posted sooner, however I was riding on the bike from about 5:30 P.M until about an hour ago. I'm not terribly upset about buying a carb float, as now the bike doesn't leak gas after about 10 minutes of sitting without the engine running.

Luckily I didn't have to get out the cutting torch, or the sawzall. :-)

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Re: Fixed!!!!!!!

don-ohio /
Jul 12, 2001 09:30PM

Hey Ron! That wasn't in vain.I copied that great info! Thanks a lot,Ron!

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