CDI problems

[mobicon]

Help! I've had my motorized bike for 3 years now, and have only been able to ride it 9 times in total. Three of those times it left me stranded because parts fail.
It is a two stroke iron horse with magneto and CDI mounted on a 10 speed Schwinn. The mag went and was replaced under warranty. Then the CDI's kept failing. The CDI's come from Bikeberry, and I'm sick of having to replace them.
Can anyone recommend a good brand of *QUALITY* CDI ignitors that I won't have to keep replacing? (Also, are all CDI boxes suitable for any type of 2 stroke bicycle engine, and if not, what do I have to watch out for?)
Thx,

 

[ZipTie]

Ouch... You have caught the dreaded CDI curse I'm afraid. Bury a chicken foot during a full moon to rid your self of it. Sorry couldn't resist . I wonder if you don't have a short and its not the cdi that's failed but rather messing with the wires gets rid of the short when you replace it. If it was me I would replace the kill switch just in case check all the connections etc. The CDIs are pretty reliable, I just couldn't imaging that many bad ones, but I could be wrong. I could tell you two cases of hands on helping people where they were convinced their CDIs were shot and I traced a bad intermittent connection. Factory connectors are junk as are factory Plug wires. Soldering connections will help. Connectors and kill switches are far more likely to fail. Then encasing all the wires in one hollow sealed small lightweight tube the size of a toilet paper roll will protect delicate connections. I use 3m double sided trim tape to attach to my bike frame and hole plugs for top and bottom to keep it all clean and waterproof. I use small chrome plated plastic pipes.
Of course I could be wrong and your CDIs are all failing.
Just pick a different supplier if it makes a difference, certainly possible one of bike Berry's supplier sent them a ton of defective ones., there are many other good suppliers with ads right here on this forum.
Below is a picture on how I wire all my bikes now. The picture posted sideways and will not let me fix it.

 

[ZipTie]

Here is a wide shot of a protective junction box for cdi wires to magneto and kill switch wires. I see many with just a rats nest of wires, that can be pulled and yanked with every ride. My cdi wires are always organized and totally protected to prevent shorts.

Ziptie

 

[mogollonmonster]

That's nifty ziptie! I likes it!

To the OP, do all the inspection described above, and the chicken foot thing too, it can't hurt. Make sure its fresh, and bury it at lunar midnight, when the moon is at it's zenith. If it is your CDI that's Dax is my engine parts guy. Period. In fact here are the list of MogollonMonster approved MB parts suppliers.
That's Dax www.thatsdax.com
Custommotoredbikes.com (same as www.mbrebel.com )
Manic Mechanic www.mmbikeparts.com
Tgats the complete list, as of today. I have no positive experience to share with other dealers, in part due to customer loyalty, and also because I've been screwed one or twice. But as of yet, those folks are my ONLY recommendations.

 

[ZipTie]

Thanks Mogollonmonster, I forgot about the zenith, oops: Me hates too much electrical tape and worse is a sticky rats nest of loose wires hanging off a nice built MB. The MM preferred list for the OP is also endorsed by me also. Lynn is my fav, she has everything for MBs except kitchen sinks. Her huge site was closed temporarily for inventory taking.

 

[crassius]

check your mag to see if it is 480ohm instead of usual 340ohm - many CDI units fail with the higher ohm mag

 

[mogollonmonster]

Thank you Crassious for that usefull information! I was unaware that there are two types of mags for these motors. That little tidbit could save someone lots of hassle.

All of you more experienced builders should get together and write up a comprehensive ChinaGirl manual, with all of this very necessary, but sometimes hard to procure information.

Ziptie, it's possible that once she completes inventory, the sinks will be available. I'll keep my eyes open.

 

[mobicon]

Thank you all for posting responses!
I will check out your recommended suppliers.
It is still a few days before full moon, so I'll have to wait on that one...

In the mean time, I'm sure it's the CDI box, I put the meter on some of the parts and got these numbers;

CDI box resistance at the leads = 2.9 M Ohm where I believe it should only be around 8 Ohm.

My Kill Switch appears to be working perfectly.

Magneto Coil resistance a steady 350 Ohms, +/- 2-3 Ohms between measurements.

While rolling the bicycle with the plug out and the meter on the mag output I got the following numbers -
Voltage output varies from ~ 2.5V up to about 6 to 10V AC at a jogging pace depending how fast I push it along, with a duty cycle of 50% and a frequency that varies with my pushing speed and is in the 20 - 40 Hz range depending on how fast I push it.

They make sense to me, but I'm sure you would know better if they are appropriate numbers?
Thx,

 

[crassius]

testing a CDI with a meter does little - they can have great spark, but still be at wrong timing