Help!! - No spark on 48cc motor (brand new)

[Watcher05]

HELP! :-/

I have purchased a Chinese 48cc motor. Have fitted motor but getting NO spark. I can hold the plug and sometimes get a mild pulse/current but nothing to boot me off the bike.

Have tested magneto: 363 ohms

Have tested CDI unite black wire to plug lead/cap: 2.3 (testing at 200k).
I've even held the blue and black wire coming out of motor/magneto and only a light pulsing.

Any ideas before I start replacing parts etc. I'm assuming that to get a spark, it only takes a bit of speed on the bike to produce something (pedaling around the back yard while clutch is engaged).

Thanks heaps.

 

[Papasaun]

I would start by checking that the connections for the cdi are in fact good and tight, (this includes the spark plug lead at the cdi). That the spark plug does indeed fit into the spark plug boot securely. If you have already wired in the kill switch, you might consider taking it out of the system for the time being (until after testing). Other than that,,,read, read, read, all the searched posts on ,,, no spark or,,, wont start.

Papa

 

[ibdennyak]

Sounds like a mag problem to me. On mine, they work at about 260-280 ohms. Past 300, and I get a weak or intermitent spark. I have 4 of them laying around right now that read 350 plus. In my case, I think it is moisture. When I get a new one it works fine, until a ride in a drenching downpour. After I shut it off, it will never start again. (I live in a rainforest, so moisture is unavoidable) My next plan is to add varnish, or repot the thing somehow when it is new. I believe Dax has a couple posts with specs on it.

If you find a different solution, or figure out why they do this....keep us posted.

 

[Watcher05]

Sounds like a mag problem to me. On mine, they work at about 260-280 ohms. Past 300, and I get a weak or intermitent spark.

If you find a different solution, or figure out why they do this....keep us posted.

It is reading at 363 ohms & have phoned zbox australia and he's under the impression that it can only be the CDI box. He said its unusal but sometimes they can fail. But won't receive it until late next week to see if it does acutally fix the problem.

 

[ibdennyak]

Yeah, on mine it seems like it takes the cdi with it when the mag is weak. I have three of them in the same box as the 4 mags. Some day I will have to take one apart to see what it in there....like to understand how they work. When you checked your cdi did you notice the resistance slowly rising like a capacitor charging up?

 

[Watcher05]

As regards to checking the CDI; it just reads as 2.3, as I'm not exactly sure what the reading should be?? But the magneto was coming up as good! Not sure if a reading of 363ohms still means that the magneto can still play up??

Also, I've managed to get some spark from it but seems to be intermittent.

I've tried to eliminate if its a fuel problem by using wd40 but it still won't ignite.

If the replacement CDI unit fails to fix the problem, I'll be sending the motor back. It seems like alot work, especially for a brand new motor!!

 

[Watcher05]

OK!

I have got the motor going, although its been a slow and laborious process. But now it has no power what so ever going up a very slight incline!! When I give it throttle it seems very sluggish.

I've searched the forums for info but nothing obvious. However, I've cleaned carby out; adjusted needle up and down but still now power. Unless its still this electrical/CDI problem!!

I'm not asking for some sort of high powered output, but I was advised before I bought the kit that it would go up hills reasonably easy (within reason). Certainly not doing that at the moment.

Please, any feedback would be helpful.

I didn't think the kits would be this much work

 

[Scottm]

You are still in break in period. Be patient, it will gain power as it goes. Some of us here have changed spark plug wires to a higer grade copper core wire. I noticed the difference on my motor.

Denny, I think I still have the CDI that melted on my muffler.( I'm a pack rat) . I suppose I could cut it open and post pics or mail it to you.

 

[alesterfeind]

Also, check your clutch adjustment. Even though it might feel like it's engaging and disengaging correctly, it seems like it has to be in just the right spot for the engine to fire. I had the same problem with mine when I first put it on, and moving the clutch slightly seemed to do the trick.

 

[fetor56]

You said u got the motor going...how?.....it's too early isn't it to have your replacement CDI.
Warren from ZBOX is good and he'll stick by u but at this stage i think your lack of power is just cos it's new and TIGHT.It takes around 300Km to loosen up properly.
You've adjusted your needle and i'm assuming you've o-ringed the carby and trimmed your intake/exhaust gaskets.