Moby not getting ignition

First time posting....

I've got a '78 Moby 50V. Just got it last week, first moped for me.

The first night riding I was fine for the first few miles. After that it wouldn't keep firing. I looked it over and figured that the spark plug was losing contact (doesn't have a normal spark plug boot...more like a fork that fits over the spark plug contact). I bent in the forks and she seemed to run fine again.

Also noticed on first night that when the headlight is on, the engine dies at idle speed. I think this is a magneto problem. Tail light doesn't work either.

I ordered a new ignition cable with boot and tried installing it tonight. The HT coil (plastic bit the ignition runs into) has a fixed screw at the ignition port. I screwed on the new cable and covered the spark plug with the boot.

Engine fired over for a little while, but was just barely running. Then died, now doesn't fire again. Swapped back the old ignition cable and still won't fire up.

Is there a good way to measure if I'm getting a spark in the cylinder? Could there be something else wrong with the magneto (seems like some of the wires could be loose)?

Thanks!

Re: Moby not getting ignition

Peter Ehinger Wrote:

-------------------------------------------------------

> First time posting....

>

> I've got a '78 Moby 50V. Just got it last week,

> first moped for me.

>

> The first night riding I was fine for the first

> few miles. After that it wouldn't keep firing. I

> looked it over and figured that the spark plug was

> losing contact (doesn't have a normal spark plug

> boot...more like a fork that fits over the spark

> plug contact). I bent in the forks and she seemed

> to run fine again.

>

> Also noticed on first night that when the

> headlight is on, the engine dies at idle speed. I

> think this is a magneto problem. Tail light

> doesn't work either.

>

> I ordered a new ignition cable with boot and tried

> installing it tonight. The HT coil (plastic bit

> the ignition runs into) has a fixed screw at the

> ignition port. I screwed on the new cable and

> covered the spark plug with the boot.

>

> Engine fired over for a little while, but was just

> barely running. Then died, now doesn't fire

> again. Swapped back the old ignition cable and

> still won't fire up.

>

> Is there a good way to measure if I'm getting a

> spark in the cylinder? Could there be something

> else wrong with the magneto (seems like some of

> the wires could be loose)?

>

> Thanks!

SEARCH THE WIKI FAGGOT!

Also, welcome to Moped Army.

Prepare to be flamed.

Re: Moby not getting ignition

Sons of GROMarchy /

^Don't mind him, he's a little edgy.

Pull the spark plug from the cylinder (with the boot on) and turn it over with the plug up against the cylinder. Do you see it arching?

Re: Moby not getting ignition

If there is no bonding strap from the external coil to the engine then try to add one from the lower stud on the coil to one of the intake studs. If the stock strap is there going to the upper engine mount you might want to change that out for the other methos because the engine mount attachment is sketchy.

Check for a nice bright blue snappy spark. If you have none you could try pedalling over the bike with the grey wire connected to a test light or a voltmeter. Having voltage at the grey wire will narrow down the hunt to either the condenser or the external coil at fault. No voltage would indicate trouble with the points or with the internal exciter coil for the ignition.

Re: Moby not getting ignition

Thanks for the help! Getting a spark. Engine turning over again. Figured out that it was a carb issue along with a sketching spark connection.

Have a Dellorto carb on it and the choke lever (on the carb itself) locks down when pushed all the way rich. Is there an easier way of unlocking this other than taking off the air filter?

Still have to sort out the tail light/magneto issues. Headlight definitely kills the engine when running at idle.

Fun stuff!!!

Re: Moby not getting ignition

they like to run the ignition coil ground to superfluous systems. even new old stock coils have trouble pulling lights on their way to ground.

Try running the ignition coil ground to ground instead of into the headlight circuit. Possibly get some LED tail lights to save some juice for the headlight.

Re: Moby not getting ignition

The Del lever choke should click off when you crank the throttle to wide open, if this is not happening to your bike then you need to adjust the throttle so it will lift the slide all the way to trigger off the choke (and allow you to be able to get full throttle as a bonus).

If you have a 2 coil 6/12v system then you need to check that the bulb is not too many watts or it is taking power away from the ignition and it will let the engine drop off at idle. If you do not have your ignition indexed and the timing set right it is more sensitive to that happening.

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