Misfire under load (plus? coil?)

[alex_rsa]

Hi all,

In the last couple of days my bike has devloped a misfire when under load. Load being pulling away briskly or accelerating faster then surrounding cars. It is driveable and I can commute quite easliy on it.

I removed the plugs last night (they have been in about 3000 miles) and they look ok. The "burn" marks on the top plugs and bottomg plugs look the same and there does not appear to be any cracks in the insulation. I also refitted them differently in the hope it may re-act differently

The coils visually look OK and all the wiring is looks ok.

I did buy another brand new plug (£9 for a single plug ) so could swap that around but I am not convinced it is the plugs.

Is there anyway to actually check the coils are working correctly or is there something else I should be checking?

Many thanks

Alex

 

[duds]

Testing coils

Only real way to test the coils is with a multimeter.

Primary coil resistance should be 0.87 ohms, measured between terminal 1 and 3 on the connector in the coil. The terminal numbers are inside the connector but are very small so you will need good eye sight and a torch.

The secondary resistance is measured with the + meter probe placed up inside the spark plug cap and the - meter probe on terminal 2 of the coil connector. You are looking for 6 K-ohms, so don't forget to set the multimeter to K-ohms.