hello, i recently had a 1979 xs400 that fell into my hands from my grandad, i have cleaned the carbs and the starter is in great shape , i am not getting any fire to the plugs though, but i put the test light to the coils wires and when i turn it over the light dims like its supost to, but still no spark from the wires, is there a way i can just get the wires and replace them from inside the coils or would i have to replace the whole coils. also what is a good way to get rust out of a gas tank?? any suggestions would be great

also its there any other coils that would fit to use for this bike. a cheaper set by chance from someother modle bike but it will coss over to mine

I'd replaced the coils on my '78 xs400 just a few months ago - used ones from Mikes XS650 site, the Part #17-6805, about halfway down the page, and seemed like a good fit - similar stats to original, fit the original mounts, and the bike runs great with them in.

If you think it might just be in a wire and want to keep the coils but replace the leads to the plugs, you might have a problem - the original coils have the lead wire as part of the unit, epoxied in place (replacements, the wire is seperate), and the only way to replace it is to cut it and splice a new one on. There's a lot of voltage there, so you'd need to track down some kind of fitting to do that splice properly.