Fabian
Well-Known Member
This post is reproduced from another thread, and it details an electrical problem that was actually easy to solve but harder to diagnose
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.
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.