IP2 ignition relay

[gripper]

My IP2 has a relay in the feed to the ignition. I'm familiar with the reason for fitting a relay to headlights, horns etc because they draw high current. Is one really required in the ignition supply? or could I just supply straight from the ignition switch? ie. a few less wires lurking under my seat. (there's fuse in there as well)

[Richard Negus]

Dave,That relay was originally there to make sure the ignition unit had the best possible voltage by a direct feed from the battery rather than the voltage drop of a length of wire up to the switch and a length of wire back again.With decent cables and connectors, it shouldn't really be necessary except that it does however allow the handlebar ignition kill switch to operate without being part of the 'live' feed to the ignition. That switch only has to carry relay energizing current rather than ignition current.

[gripper]

Thanks Richard, good point about the cut out switch, never use it myself. food for thought though.

[Richard Negus]

Dave,I've only ever HAD to use the kill switch once, and that proved its worth.At Rugeley, a rebuilt Classic to run in for the owner, several hundred miles completed, and I gave it a fistful to get past another vehicle. The throttle stuck open, and I rode it back to the workshop using the kill switch.A simple thing really. One of the oil pipes to the centre plate was too close to the throttle lever and the spring hook had caught over it the first time I fully opened the throttle. As I always check that clearance when the engine is on the bench, I assume the pipe got bent when the engine was being re-fitted into the chassis. Checking with a quick flick of the grip isn't always enough - wind it to full throttle position!