My 3EN1 had the the side stand switch removed by a previous owner. I've been having some intermittent issues with the bike being difficult to start, tried the usual suspects, and don't know if this may be the cause.

Problem is I can't see where it would have originally been connected to the main loom to see what they did with the connector that end. Can someone point me in the right direction please.

Have a look at the 3tj wiring diagram in the Document Library - it won't show where the wires are in relation to the bike but at least you'll have an idea.
Not a very clever mod.

They often have a wire and plug about a foot long so have a look for the plug socket somewhere near that distance away from the switch.
Can't remember if it needs connecting or disconnecting for it to work though.
Kill switch, clutch switch (if it has one), ignition barrel also cause intermittent starting.

Thanks for the suggestions which have helped. I also managed to find a fairly decent photo of a 3EN1 loom and think I know where it's supposed to go. There are four main branches of wires coming off the loom, by the TCI/solanoid, near the battery tray, in front of the carbs and up by the front headlights.

Near the battery tray there is a light green two pin female connector (the only one) so I'm guessing that's it. Too late in the evening to go out and check my bike now but at least I know what I'm looking for

I thought it was black. The wire goes from the side stand, under the sprocket cover and up to join the alternator cables, they run under the carbs and into loom above the starter motor.

The circuit needs to be closed by the side stand pushing the button on the switch in, or, the bike can be in neutral, or if it's in gear the clutch in pulled in (the clutch switch is in the lever perch). The stand switch can be bridged by a wire loop in the connector or if you're less lucky the wires will be stripped twisted together and insulted with half degraded electrical tape.

Ok, I have gone right through the loom on the bike and cannot see any sign of a connector for the side stand switch.

I have even got a second hand loom and laid it out on the bike to compare it with the one that is fitted and it seems they are identical and the fitted loom is correctly connected up. Neither one shows signs of having had a connector removed/cut off.

Comparing the 400 loom to my 600 loom (1989) I can clearly see the extra connector (blue) for the side stand switch on the 600.

Looking at the side stand itself I cannot see how the switch would be mounted to the frame.

Is it possible that the 3EN1 didn't have a side stand switch when it came out of the factory?

Possible I guess they added it at some point

3EN1 parts book does not show the sidestand switch.
Nor does it show the pivoting bracket that operates the switch plunger which is shown on the page with footrests and sidestand on the later 3EN2.

From this it appears not to be fitted.

Cheers everyone, and Will thanks for looking that up I just assumed it would have one (seems all the other FZRs do). So that's put that one to bed and on with the elimination.

I reckon now that my intermittent starting problem is now down to the fuel pump and/or carbs. The relay is fine, swapped it with some spares, and the pump will run every time without fail if it isn't plumbed up to the carbs but when connected it wont always prime. Hoses are fine and not kinked and fuel filter is new. So I think it must be the pressure sensor inside the pump or a problem with the floats. I'll start with the floats first.

If you a long fuel hose you can gravity feed the carbs. If it runs Ok then it's not the floats