S1 Publishing(Oxford)© 1999-07

World of motorcycleS
S1 Publishing(Oxford)© 1999-07
The coil changes the 12 volt electricity to a much higher voltage, then releases the charge for a split second to the spark plug through the HT lead and the cap, there are several types of coils around, if you have to replace one it's best to replace one from the same model of machine.
Singles One coil, one HT lead, one spark plug, checking the coil for a single coil is harder than for those with two or three coils. Firstly I'd clean the two cennections and retry, on older coils I'd then tighten both ends of the HT lead (a continuity tester will test the wire in the lead)
To check sealed units, I clean the connections and check for a spark, if nothing happens,  I usualy have a deal with my breaker, he'll let me try a coil from another machine (on pay or return).

A coil from a single, the HT lead (in white) goes to the cap (in red) this type can be changed seperately.
Twins , there are usualy two coils,  if have no spark on the left HT lead, check the right hand side HT lead for a spark.
 There are a few twins which run double HT leads and only one coil. To check these the same way as you would for a single.
 These either have 2 or 3 coild depending If you have three you can test each coil seperatly.
 Two coils which have two HT leads coming from them are usual for four cylnder machines. They usualy have two sets of coils, each of these coils run the spark for two plugs, on my machine they run 1 & 3 or 2 & 4 pot. So if it's a coil problem, you can check it, if 1 & 4 run a spark but 2 & 4 didn't, I'd know that one of the wires or connection leading to that coil needs cleaning. After cleaning the connections, I'd check for a spark again. If no spark is found, I'd know that the coil will need replacing.
More than four
 Sorry, I don't know much about those, Mostly likely though they will run coils singly or as two pots at a time, or they will run a distributer like a car engine does.
Under Construction!
This is just a general guide.
If you are about to do your own maintenance, using these pages, I take no responsibility if you get things wrong!