Newbie with CDI wire color puzzle

[skeech]

Hi all. I'll just jump in ... 'Just received a kit that professed to be 80cc 2-stroke from Power King Shop on ebay. The CDI has a Black and a Green wire while the engine has a Black wire, a Blue wire and a White wire loop (no end). The four paragraphed (not much longer than this message), poorly translated instructions I received didn't meantion this configuration but I did find a useful link on grubeeinc.'s page (their skyhawk 80cc seems to be the same general model) but alas it says to attach matching colors. I don't care to burn up the CDI with an incorrect guess.

It also says to connect the kill-switch to the white wire on the engine but doesn't meantion its a loop. I could strip the white wire and solder the kill switch to it but should I ? It's likely that one end of the switch is actually connected to switch mount so that you're pulling the other post/wire down to the bike ptential and I'm also guessing that the dynamo in the engine is grounded to the engine/bike - so it smells like I should just strip and solder....

But what of the CDI to Engine wiring? Thanks!

 

[gone_fishin]

this outta do it: wiring help needed! (magneto/CDI wiring) i think that white wire might be mistakenly placed, maybe the end's just tucked back in? it should be 3 wires from magneto, never heard of a "loop" before, got a pic?

welcome to Mbc, skeech, stick around & keep us posted on how that goes 8)

 

[Steve]

Welcome to the froum, Skeech. I would wire black to black, and color to color from the CDI to the coil. I have my white wire hooked to the kill switch, but have never grounded the other side of the kill switch, so it does nothing at this time.

Being just down the road from you close to San Antonio, I will be interested in hearing how you and the motorbike get along with Austin's finest.

 

[skeech]

Thanks for the forum link. 'Hadn't noticed that there were other pages in the Technical Help section. More to read, but even more value than I first thought, and I was already surprised at the large amount of useful info in this forum.

Don't suppose anyone had derived a schematic of the CDI and Magneto ?

There has to be both timing info and return path in thoses two wires given that the coil /sparkplug lead pratically can be eliminated for those purposes. The nature of the pulses coming out of the magneto defines likely circuitry in the CDI. If it looks like rectified sine waves like out of a DC gerator, or unrectified AC in sine wave form, the trigger can be simply a voltage at a particular percentage of the previous peak -- probably not TOO dificult to design. However if its some kind of a square wave, then you,ve got to determine the period and then take a percentage of the TIME.... it would take a timer, uP based or not, which would need a regulated supply....getting more difficult and costly...

Maybe messing with the such dwell timing, especially but more difficult relative to torque (load) and rpm, would be a useful place to seek more power and/or efficeincy in these engines? If I get the engineering job I'm going for next week I'll be able to afford an old oscillascope to better develop this concept further. If some of you guys pray for that to happen it more likely will, IMO.

Skeech

 

[tirebiter]

Good luck with your job Skeech....and Welcome

I work in an R&D engineering lab and like it a lot.

 

[gone_fishin]

Thanks for the forum link. 'Hadn't noticed that there were other pages in the Technical Help section. More to read, but even more value than I first thought, and I was already surprised at the large amount of useful info in this forum.

thank you for the positive feedback

good luck, i hope you get the job... 8)