25-10-25, 09:53 PM
(25-10-25, 09:22 PM)unfazed Wrote: I have SD10F (10Kohm) fitted to my sons bike and they work perfectly, even with 10mm cut off the ends of the coil wires.. These match the resistance of the original plug caps.
The standard resistance in the coil and plug circuits is 15kohms and this is what it is designed to use. Caps 10Kohm and Plugs 5Kohm.
The more common are the SD05F (5Kohm) and work well also.
The original caps are still on my own bike but are fitted with NGK 10Kohm resistors (removed from a set of SD10f caps) and used the NGK top and bottom boots as they were tighter on the cap. I just prefer the look of the original caps as the bike is almost totally standard looking.
They are a better quality resistor as they are wire wound with stainless ends compared to the originals which are Carbon resistors. These carbon resistors breakdown and/or crack and breakdown sending the resistance into megohms. This is the cause of the misfiring and arcing, now add water ingress and you have a recipe for disaster as this corrodes the worlds smallest internal shim and internal spring.
Fitting the NGK resistors allowed me to do away with the shim which was broken in two caps and badly corroded in the other two caps, but I was able to clean up the corrosion on the spring and the internal corrosion at the brass flat top end of the cap. The inners of the original caps can be removed by undoing the internal screw with a wide flat screwdriver and everything should fall out. If the spring sticks, a phase tester size screwdriver will dislodge it.
I was told recently by the NGK distributer in Ireland that NGK will no longer be making Plug caps, as there is little or no demand for them due to the the prevalence of Coil on Plug set-ups.
Very interesting! Electrics aren't my strong point (if you can't tell ?), so I appreciate the extra info! I wonder if water ingress could be an issue here for me then! The garage does get slightly damp inside ? Looks like I'll take it all off and investigate at some point in the next week or so when I have some time. I just want it back to running how it was as it's such a nice bike! Plan on doing some routine maintenance early next year but there's no point in me doing that until I get the engine running good again lol