Can anyone help us with a problem on my son's 2005 DT125RE.

There is no ignition spark at the spark plug when turning the engine over with the electric start and then a weak spark appears as the electric start is released.

We tried a new spark plug, cap and ignition coil with no change.

Further checking though the workshop manual and the source coil resistance should be around 300ohms but is giving a resistance of 32,600ohms! So that looks to be the poblem.

We have tested from the plug on the wiring loom but there are no instructions in the workshop manual on how to access the coil - it looks to be located in the magneto. Can anyone tell us how to access the source coil and if any specialist tools are required - is thia a job for the amatuer mechanic?

We also can't find a replacement part identified other than a complete magneto - can the coil be bought separately and where from.

Any advice really appreciated.

Thanks.

I take it you have checked stuff like the battery, major earth connections, etc. The battery isnt actually part of the ignition systems on these so the starter will have little effect.

Poor engine earth or something like is what i'm thinking. When you have the starter pressed there is too much power to allow the plug to spark, then when the button is released it tries as the energy dies out of the system.

Does it have a kicker? Have you tried bumping it.