Cursed bike destroyed CDIs

Mr.2Tcycles

New Member
Nov 13, 2008
44
0
0
Hawthorne CA
OK I think I just bought a cursed bike. I just bought a non functional one, with no spark and replaced the magneto, thinking that was the problem, still no spark. So I thought I would switch out the CDI from the broken bike with one from my other MB that was running great the day before. Still no spark. Switched the CDI back to the running bike and now the bike that was running great yesterday has no spark. Wires connected right blue to blue, black to black, etc. Measured output from magneto of both bikes, and there was output on the multimeter, by that I mean pulses were put out, although voltages were really erratic. What could cause the CDIs to just die? Are they really that sensitive? Also checked if the plug wire and boot were continuous, and they were. I'd really hate to spend 50 something bucks in times like these for 2 new CDIs. Anybody have any ideas?
 

europorsche914

New Member
Jun 18, 2008
168
1
0
Lancaster, PA / Newark, DE
i know when i torn my bike down and seperated the cdi from the magneto wires, my bike would not start when the wires were reattached. My problem was the contacts on the clamp on connectors were oxidized. I cleaned them and it worked perfectly!!
 

Mr.2Tcycles

New Member
Nov 13, 2008
44
0
0
Hawthorne CA
Is there a way to check the CDI, maybe by connecting it to a 6 volt source then removing it and have the spark grounded on the negative/black side?
 

jasonh

New Member
Jun 23, 2008
1,590
0
0
36
Longmont, CO

Mr.2Tcycles

New Member
Nov 13, 2008
44
0
0
Hawthorne CA
Here's what it was guys, bad connection between the cap and the wire out of the CDI. Information for the readings of the CDI were a great help in determining if they were cooked or not. The few copper wires in the high voltage wire out of the CDI were all torn, and were intermittent in the connection. Thanks for all your help.
 

jasonh

New Member
Jun 23, 2008
1,590
0
0
36
Longmont, CO
well that'll work I guess, haha. Keep an eye on that wire, the vibration will probably cause it to loosen or break.

....don't go near there when the motor is running unless you want a good shock :)
 

Mr.2Tcycles

New Member
Nov 13, 2008
44
0
0
Hawthorne CA
It's just temporary, I hate having broken things around. As for the shocking done that with these bikes and other engines too. Electrifying experiences.
 

Technocyclist

Motorized Bicycle Senior Technologist
Jul 7, 2008
463
0
0
Asia
OK so I ordered some spark plug wires and boots from SBP, but in the mean time this is what I did, seems to work really well. I have noticed a slight increase in power in both bikes since doing this.
That is exactly how they connect the cables to the spark plug in motorboats in the Philippines. :)
 

Mr.2Tcycles

New Member
Nov 13, 2008
44
0
0
Hawthorne CA
Got the new wires and boots from SBP really quick. Bikes seem to run even smoother with a touch more power. Wires and boots seem well made and have a carbon core, I'm very happy with the purchase less than $10 for both wires.