Starting to give up on this bike now . Right basically my bike has a temperamental fault sometimes it will spark sometimes it won't I've tested everything with a multi meter I've checked the pulse generator at the connection under the seat I'm getting about 103 ohms which to me seems fine . I'm getting a good 12 volts at the coils so they seem fine I've also had them off a tested them they are good . So only thing I can think of now is that the cdi is dead . No the problem I have is all the part numbers have rubbed off over the years now I'm stuck as I can not find what part number is correct for my bike . The bike is gk76a 400 rn model and I be leave it is a 1991 to 1992 any help before going buying the wrong bloody cdi cheers Louis

The thing that makes the difference between whether a new CDI will or will not run your bike is the trigger wheel (the item that is mounted on the left end of the crankshaft). There were two versions of the trigger wheel used during production of the GSX-R400 and the GSF-400.

There were more than a few different CDIs used during the years of the production runs of those two bikes, but as long as you get the CDI matched with the proper trigger wheel the engine will run.

Here's a picture of the two different trigger wheels that were used during GSX-R400 and GSF-400 production.