| Dean, Kill switches aren't normally designed to take the current required to run a bike, although you can get away with it, that is until it gives up the Ghost as the one on my CBR6 did half way round Gerrards in 1998.
If you want to do away with the relay I'd replace it with a 10 Amp Switch from Maplin and do a bit of rewiring.
As for Solinoids there are plent around that do the same job and without the stupid 2-pin connector that causes enough problems of its own. There are some around off Jap bikes that are far better suited to a race bike as they provide the +12 Volt take off for the Harness and some also house the main fuse
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