Thread: Piranha/YX 150 in my 69

I've decided to go the chinese route for the powerplant of my first CT project. The motor is 12V, and I'm starting with a bare frame and building from there. The bike will see street only use so 12V lighting will be a welcome addition. Does anyone know of a harness I can purchase that will plug into the YX/Piranha engine that has the provisions for turn signals and the like? Can I buy one maybe from a clone that would be plug and play? What else will be needed besides a regulator and 12V battery?

The search button is your friend,theres a wealth of topics on your conversion. Check out dratv and chp also(google them). Welcome to the site!

I've done multiple searches and almost everything yields me how to do a 12V conversion with the original wire harness. My bike doesn't even have one right now so I thought it might be easier to go with the 12V harness and everything right off the bat.

Best bet is to source the wire harness & schematic from the vendor who sold you the engine. Failing that, best to shift your thinking. First off, a CT70 wiring harness isn't that complicated. The odds of finding a plug & play CT70 harness for this engine are pretty slim, so best to think in terms of creating your own custom harness. Just a question of whether to adapt a K0 harness or go completely from scratch. IMO, the former solution is cleaner & easier, since it will have all of the lighting, horn & ignition switch connectors & modular plugs, plus the correct OEM color coding. Repop harnesses for this model are readily available & cheap, too. From there, you've got some detective work that's nowhere near as confusing as it might appear at present.

Hopefully, you at least have a stub harness to connect your CDI. That's the "big 50%" of the battle. I've seen 4, 5 & 6 wire CDI setups and the color coding varies, very confusing without a schematic. Once you've got the CDI leads sorted, what's left? Answer: the charging circuit, lighting circuit, neutral light lead and maybe the primary coil trigger lead. The charging(+) lead is usually white and goes to the regulator/rectifier input, then from the output side of the r/r to the + side of the battery. The lighting circuit is typically coded yellow and gets split between headlight power and the rectifier input of the r/r. That takes care of 3 of the 4 r/r terminals, guess where the 4th goes...ground bus lead. Process of elimination will make life easier as you progress. Okay, the neutral lead should be light green w/red trace; if not, you can trace that one to the source, just above the countershaft. If there's a coil trigger lead remaining, that'll be easy enough to figure out; one end goes to the primary coil input, the other end to the CDI bundle.

Your engine electrical outputs may be some variation of what I've outlined. This still ought to get you headed in the right direction.