NOTE: the handlebar MUST be grounded (earthed) for either the starter or the horn to work.
This may not be obvious to everyone - but if you set your multimeter on ohms (looks like a horseshoe) and touch one probe to the handlebar and the other to the negative battery terminal - or to the top of an acorn nut on the engine cylinder head or to an exhaust stud acorn nut - the meter should jump to 0. If it doesn’t, check the grounding of the bars and fix it or nothing will work.
This ground connection of the handlebars is accomplished in several different ways and all are vital:
- There is normally a little ground wire from the wiring harness to the underside of the stud that fastens the handlebar mount on the LH side (just under the speedometer).
- Also - the parts of the bars that are secured by the clamps to the upper triple-tree MUST not be painted. They must be bare (usually chromed) metal and those clamps must be clean and tight.
If the handlebars on an XS650 are not grounded - you have a problem - and you
must fix it before moving forward with wiring.
The other
gotcha in the starter circuit is the starter safety relay (SSR) which prevents you from engaging the starter with the engine running (which would destroy all those cute little gears). The SSR lives under the right hand side cover in a little metal cover. The relay can become corroded and if that happens, your starter will be dead as a doornail.
NOTE: do not jumper the SSR - it is an important safety feature of the bike and you need it to keep you from wrecking your starter and possibly filling your engine with broken gears and other metal debris).
To clean the SSR - just remove the little cover (two VERY tiny screws - don’t loose them!!) and carefully clean the contact points with a business card or a small piece of fine sandpaper. You might want to give the whole thing a little squirt of electrical contact cleaner too. Then button it back up and try the starter.
I clean the SSR on Lucille about once a year just to keep things “happy”.