Normally it's the big connector on the lhs of the speedo.
Buy some switch cleaner, spray loads on the connector and re-assemble , also do the same with the connector behind the offside rear wheel (thats if you have a connector, some of the early models didnt!) and also whilst the instrument pod is exposed spray the two connectors on the rhs of the rev counter.
After you've refitted the instrument cowl leave both the air vents off so you can get access (only just) to the connectors because sometimes you wiggle them back to life.
I went 7 months putting up with intermit speedo , so far I've had 3 months of uninterrupted operation - doh!,,,,,sods law says it will go faulty tonight then !!!!!!!!!
