Hitchcocks Forum

Hi, about a month ago I did a 220 mile round trip to work on my 2016 C5 classic: 2 - 2.5 hours each way. On the way down, there was torrential rain for about an hour and a half. When I hit some slow traffic, I noticed that the engine was idling way too fast. When stationary, I had to turn the bike off several times as it was just revving worryingly high. On the way back, everything was back to normal and has been fine ever since. Is this a common problem? Any ideas how to prevent a recurrence? Thanks, Tom.

No, not a common problem. My guess is that water got into one or both of the throttle cables or bi-starter cable causing the throttle to stick open a little or the bi-starter "choke" to stick on. I'd lubricate the cables and check that the throttle shuts properlly. Also check that there is free play in the bi-starter cable. The original cables on these bikes are not of high quality; our hosts sell better ones.

Maybe water got into the throttle twist and it was not returning fully or... maybe it was your bike saying, "I'm soaked and I want to go home."

My guess (and to be fair, we’re all only guessing!) is that ingress of water caused one or other sensor to play-up and create a false response from the ECU.

Thanks guys. I think intuitively, my guess is with @presto, the revs were much higher than I could have achieved with with the bi-starter cable (though I suppose could have been throttle, but that felt like it was moving OK). I sort of suspected an exposed sensor or connection somewhere - a lot of the electrical connections on the C5 seem a little 'out there'. I sprayed every sensor and connector in sight with a liberal does of WD40 when I got back. In the winter care 'news' our hosts recommend: "Silicone grease (97074) is a waterproof lube ideal for all electrical contacts and components with countless other uses too." - Are there any particular connectors or sensors that might be worth slapping some silicone grease on, and if so, whereabouts on the bike are they hiding?

Silicone grease comes in spray cans also, every month just give the whole bike a blast of all the good stuff, seems expensive at the time but down the road not