New everything and still zero spark

[batteway]

Alright then, heres my problem. Motor was running great for months and then boom! No spark! and of course 6 miles frome home. Have been through everythin including replacing everything. New magneto and magnet, plugs, wires, and a lightning cdi and still no spark. I dont know where to look anymore so any help is much appreciated.

 

[BigBlue]

What engine do you have?

Chris
AKA: BigBlue

 

[batteway]

Pk80 with cr.machine top end kit. 6.0 cc head. Sbp pipe, the only thin I have left to replace would be the bottom end. Was looking at the dax but not sure if it will allow me to use the top end I have.

 

[Fabian]

Alright then, heres my problem. Motor was running great for months and then boom! No spark! and of course 6 miles frome home. Have been through everythin including replacing everything. New magneto and magnet, plugs, wires, and a lightning cdi and still no spark. I dont know where to look anymore so any help is much appreciated.

Sounds like we are suffering from an almost identical problem and have used almost identical problem solving methods.

My situation is a little different in that the engine runs, but it has a persistent "spark miss", or what feels like a spark miss below 3,300 rpm; getting progressively worse as the engine rpm is lowered.

I have changed the entire electrical system with new components, including 2 new magnetos and one old magneto from another engine that works. I have changed two brand new Jaguar CDI's and one Jaguar CDI from another engine that worked correctly, as well as installing an original OEM CDI.

I have changed three sets of Magnecor spark plug leads (all brand new) and 3 new NGK spark plugs.

I have changed out the original Jaguar coil for 2 brand new Jaguar coils and also the coil that's included in the standard CDI.

In desperation i have also removed the original engine (which was a rebuilt engine) and replaced it with another fully rebuilt engine, then in further desperation i have installed an engine that previously worked well, but was removed because i lightly scratched the crankshaft trying to replace a crankshaft seal.

So in total i have replaced the magneto 3 times - the CDI 4 times - the engine 3 times - the spark plug 3 times - the spark plug leads 3 times - the coil 3 times, if you include the coil in the OEM CDI.


and

the spark miss replicates itself in every combination i try,

oh yes,

and i have been up and down with jetting and removed the diaphragm carburettor and gone back to a standard NT carburettor, followed by purchasing a brand new NT carburettor.
The end result is that the spark plug miss is ever present.

I have even tried making up batches of fuel from different fuel companies.


This is the first time in the history of playing around with these 2-stroke Chinese bicycle engines that i "can't" fix the problem, and yes, the killer switch is disconnected from the ignition system and the (magneto) white wire is isolated.

 

[Fabian]

Pk80 with cr.machine top end kit. 6.0 cc head.

I am using the same cylinder head. It's proven to be an excellent design; allowing much cooler cylinder head temperatures than any other cylinder head i have tested.

 

[Sgt. Howard]

Have you looked at the magneto ground connection? That's where I found a cold solder joint to the magneto frame... re-solder that wire to a round lug and connect to a mounting bolt, see if that don't cure it

 

[BigBlue]

Have you looked at the magneto ground connection? That's where I found a cold solder joint to the magneto frame... re-solder that wire to a round lug and connect to a mounting bolt, see if that don't cure it

I agree.

Also look at Grubee website about installing a new magneto coil: http://www.grubeeinc.com/USA/Magneto Mystery.html

Chris
AKA: BigBlue

 

[Fabian]

How likely is it that 3 magneto coils would have a bad ground connection (two of them being brand new) and a magneto coil that worked perfectly on a previous engine?

 

[velzie]

Maybe rust on the ground to the magneto? Try sanding the connection...

I feel for your problem as I went through something similar. I can only suggest getting a multimeter and testing all electrical signals from the magneto through the CDI and to the spark plug.

Good luck.

 

[Fabian]

Maybe rust on the ground to the magneto? Try sanding the connection...

There is no rust.
I have sanded the ground wire connector and the back of the magneto coil arms to ensure a good earth.

Luck is eluding me, and i'm having great trouble accepting such a concept. The only thing that can solve this problem is a Feng Shui expert; with typical advise to place threatening lion statues at strategic points around the bike, to cast out evil electrical demons.