Lack of power?

B

bitsnpieces

New Member
I'm just wondering, the CDI units that are provided, are they very specific, or generally the same?

That is, I have two CDI units, one from a kit on a 200watt engine, one from a kit on a 1400watt engine, both 50cc.

So one is obviously more powerful than the other, so is the CDI unit specific to them, or will the CDI unit from the 200w work with the 1400w engine?

I ask because of a problem I'm having here:
http://motorbicycling.com/f34/motor-wont-keep-running-26093.html

I'm sure my fuel is primarily petrol now, so once I have the engine running and know it's working, I'll refill the tank and remix the fuel properly.

I don't think anyone read my comment about using a CDI unit from another kit.
 
Any definite confirmation on that? CDIs generally all the same?

If that's the case, something's playing up on my motor. :S

I can hear it rev when I use the throttle, very little though. I have to keep pedaling to keep the revs up and the engine going; faster I pedal, more revs there are.

As soon as I stop pedaling, engine starts choking down.
If I pull the clutch while pedaling, engine stops.

I grounded the white wire by sticking it between the washer and the muffler, so it's not on the engine or any part of the engine, just on the chrome muffler.

Engine has the spark plug on a 45 degree angle, so I'm having trouble taking the spark plug out as it seems to not fit the standard Australia spark plug sizes and being on an angle, my tools are jammed against the grills so I can't get a good grip or turn.
 
i don't think it's the CDI that's causing your problems.

for one, if you're not using the white wire for the kill switch or lights, it should be taped up, NOT grounded. if you ground it, the bike shouldn't even start.

but as for the CDI question, i'm pretty sure they're all the same, but some do work better than others, but that's probably just poor quality control.

i worked on a bike that was a real pain to start. like, you'd have to pedal half a block to get it up to speed before it would fire.

i soldered all the wires, made sure it was hooked up perfect, and there was no change.

i switched the CDI with another one and it fired up right away.

then, to double check, i put the old one back on and it had the same problem. put the other one back on and it worked fine again.

i keep meaning to cut the bad one apart and see if i can mess with it, but just never got around to it.
 
Tape up the white wire? Hm... I just remembered my previous kit had it soldered inside the magneto cover itself, so it wasn't even outside of the engine.

So when you say tape it up, you mean just leave it out, tape it up with duct tape so it doesn't get wet, and just fit it somewhere snug to be safe?
 
tape up the end with electrical tape or heatshrink, or anything so it doesn't make any contact with anything and ground out.

originally, the white wire was used for lighting. that doesn't seem to work very well for most people.

now most kits say to use it for the kill switch. when you push the button, it grounds out and kills the motor. so if the wire is grounded, or flopping around and making contact with the frame, it should kill the motor.
 
Wish I understood this terminology more...

Just to be clear, basically tape up the wire, and that's it.

Tape it onto something to hold it down afterwards is optional?

Well, nonetheless, I hope this works and gets my bike going.
 
Update: PERFECT!

Thanks bairdo!

I taped up the white wire and stuck it underneath so that it would be out of the way, started it up, and it ran beautifully!

Now to do the run in process. Woot!
 
cool, glad you figured it out. i'll over-simplify what i was talking about.

the reason for the tape is to stop any chance of a bare wire (the metal part inside the white plastic outer cover) touching a metal surface (frame, motor, etc.)

if that happens, a "short" occurs and shuts off the motor.

taping it out of the way is a good idea, too.
 
What metal part in the white plastic outer cover? You mean the brown metal strings?

Just kidding. :P

Thanks, now I see why it wasn't working. Didn't realise it was causing it to short out the engine to cut it. It was like constantly starting and stopping my engine, ouch!
 
You must log in or register to reply here.
Back
Top