Cranky- New 1978 AMF Roadmaster

Rich Sutherland /

My brother does estate sales for a living here in the PDX Oregon area, during a sale few weeks ago he ended up with a 1978 AMF Roadmaster, brand new, unassembled, still in the sealed box. We put it together and got it running, it needed a new fuel hose but other than that it started right up. We ran about half a tank through it with no problems. I thought it was cool so I made a deal with him and took it home. Now it doesn't seem to have spark, I can sometimes get it running for about a block then it quits. I have replaced the spark plug and made sure it has fresh gas. When I checked for spark with the plug out I didn't see any. Does anyone know if this thing has points or electronic ignition, Should I try to pull the magneto cover. Hmm, I'm just not sure what to do and my legs are tired from pedaling it. Maybe I should sell it.

Any ideas would be much appreciated.

Thanks.

Re: Cranky- New 1978 AMF Roadmaster

Should have points ignition. don-ohio

Re: Cranky- New 1978 AMF Roadmaster

Leon Swarmer /

errrrr, You did use 2 stroke oil fuel mix didn't you??

Re: Cranky- New 1978 AMF Roadmaster

is the the roadmaster with the minarelli engin or does it have the rear mounted engine?

Re: Cranky- New 1978 AMF Roadmaster

Jason Luther /

check the gap on the new plug

Re: Cranky- New 1978 AMF Roadmaster

Rich Sutherland /

It is the rear mounted, McClolugh(sp?) engine.

I used fresh gas and fresh 2 stroke oil mixed to 1 part in 40

I gapped the plug.

BTW: Because it was "new" in the box, I have all the original manuals for the frame/bike and engine. Not very helpful.

I tried running it again and same results- kinda runs, then backfires and sputters as I keep pedaling until my legs turn to jelly. I am getting farther each time as my leg strength improves.

I think I need to get the magneto cover off and take a look/see at the points and replace the condenser, if I can.

Have to come up with an impact wrench as there seems no way to keep mag cover/flywheel from turning. hopefully it will come off after nut is removed.

Re: Cranky- New 1978 AMF Roadmaster

You might think about a nylon cord in the sparkplug hole to stop the piston. That will enable you to twist on the nut without the engine turning over.

Re: Cranky- New 1978 AMF Roadmaster

Rich:

I have 5 AMF mopeds. Don't look for condenser or timing, because the '78 AMFs all have a "potted" electronic ignition. The last note I saw was a good one! Stuff a rope in the spark plug hole, to keep the engine from turning over when you remove the flywheel nut. Be careful with that nut, it is metric, and a bit unusual.

Re: Cranky- New 1978 AMF Roadmaster

Rich:

Also, be careful when removing that electronic ignition. Make sure the wire clips both front and back are carefully removed and mapped. check to see that the front clip (back side) is not accidentally grounded! This is the "engine cut off", and is actuated when the engine is "lifted". Also when removing the electronic ignition, remove the holding nuts at the ends, then carefully pull off - there is a plastic button on the back that inserts into the engine casing, and is easily broken off.

Let me know if you think you need another electronic ignition.

Re: Cranky- New 1978 AMF Roadmaster

Harry,

I also have a 1978 AMF Roadmaster that has been sitting for many years. A Google search located your post at mopedarmy. I also have no spark. Years ago, as a young electrical engineer, I worked on development of electronic ignition modules for chainsaws, so I know a bit about them. I suspect the high voltage coil (part of the ignition module has partially shorted because the resistance is only 2800 ohms. In my experience, this is quite a low reading. I have been cranhing the motor with a drill motor, and discovered the engine kill switch that kills the motor in the UP position, so I disconnected the kill wire from the module

Any information you could hook me up with would be helpful, such as, how to determine if the module is bad or not (voltage checks, resistance checks, etc.) Where can I get an ignition module? I'm afraid the cost would be pretty high?

Thanks,

Gokartron@yahoo.com

Re: Cranky- New 1978 AMF Roadmaster

Rich

Take the spark plug out, and stuff a rope in the spark plug hole. You can then use a socket wrench to remove the nut.

Sounds like the electronic ignition unit is OK, since you are getting some spark. Sounds like maybe the woodruff key on the shaft (under the flywheel) may have sheered, or slipped, because it sounds like you have a timing problem, and that is "fixed" by where the magnets in the flywheel are mounted.

Re: Cranky- New 1978 AMF Roadmaster

George Mikesell /

R&D May Co. 152 W Mill Street Bloomfield In.47424 Phone 812-384-3612 Has Engine repair manual showing how to check electronic ig. Plus has engines, and Parts. I need a twist throttle with switch, can you help?

Re: Cranky- New 1978 AMF Roadmaster

George Mikesell /

Dear Sir: R&d May Co. 152 W Mill Street Bloomfield In. has engine service manual that tells how to test you ignition plus tool to hold crank shaft from turninng. Be sure to take the black lead wire loose from kill switch, Under the handle that raises the motor. The switch mounting rubber gets bad and shorts out the ig. Ps I need a throttle twist handle and switch for a 78 AMF Roadmaster can you help?

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account