Gremlin Found….eventually

Either side of a trip to Paris, I managed to resolve the electrical problem with the Transalp I encountered the previous weekend

After the pushing the bike back the mile into the workshop, I though it was going to a fairly trivial exercise in finding the problem connector and getting the bike running again.

Running round with multimeter didn’t locate any problems and it still wasn’t clear while I wasn’t getting a spark on any of the 4 plugs. Whilst in Paris, I located the official Honda manual for 1989 VK models and downloaded it. It provides more information of the electrics that in the Haynes manual, though the latter does have a colour wiring diagram.

Back in the shed, it seemed to me that the ‘safety’ features (neutral, stop switch etc) were the likely cause. Its not explained in the Haynes clearly, that the for the 1st two years, the models (VH, VJ ) came without the sidestand switch, so at least that removed it from equation. The neutral switch and been intermittent for a while and meant the bike would only start with the clutch pulled in, so a new one was ordered from David Silver Spares along with the much needed plug spanner.

Fitting the switch and checking this circuit still didn’t resolve the problem, so moved onto the rectifier / regulator. Whilst not part of the ignition circuit, it might be a problem. Using the chart in the Honda manual infact condemned it, as where there was meant to be continuity there was none. However, bit wary of these results and moved.

The dodgy connector

Checking the input to the CDI units revealed an interesting result. The black/white feed (via the stop switch) should have provide battery input with the ignition on, but only showed 2v, rather than 12v. The voltage at the switch was correct on both sides, and with assistance fro m Gavin who come round to assist the problem solving proved this, as taking an independent feed from the battery to one of the CDI units produced a spark.

It then took another 30 minutes or so to locate the offending connector, underneath and to the right of the instrument block. It was leaking to earth and after a clean-up and spray with contact cleaner, the bike was back running.

CDI units

So the moral of this tale:
– the electrical connectors on a 23 year old bike, do need checking and cleaning, even if it is a Honda
– than even on a fairly simple circuit like the Transalp, there is still of work needed to track down problems.
– both the Haynes and the Honda manual do not provide enough information on the electrical system for your bike; the rectifier tests in particulatr are misleading and could induce the unnecessary purchase of a new unit
– get it there: the only way to understand the electrics is to use the wiring diagram as a map and work your way around

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