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Up Topic C1 Information / Repairs - Faults & Fixes / Crank Sensor testing/replacement.
- - By HelmetHair Date 01.10.19 09:28 Edited 04.10.19 08:44
Bike is currently not starting. I have determined this to be a problem with the crank sensor, as there is no fuel being injected (the pump works) and no spark.
On closer inspection, I have found one of the generator yellow wires is broken about an inch from the casing-so it can be fixed without removing the engine cover.

I checked the crank sensor connector. Infinite resistance for wires headed to sensor. So that issue is confirmed.

Tomorrow I’ll strip the bits away and find if it’s a broken wire outside or inside the engine casing!

late last night I tested the resistance of the wires coming from the crank sensor, and it is "open circuit" (ie infinite resistance-no connection).

Form past experience, I recommend a heat gun and shrink wrap insulation, after soldering the wires together, to repair any broken wiring.

It is possible, but fiddly, to open up the connection for the crank sensor without removing any panels and testing for continuity with a Ohmmeter.

If you find the readings to be open circuit, remove whatever you need to on the right hand side of the bike to get a better view of the wires from the crank case.

If you insert a pin or needle in to each of the wires, you can test for continuity up to the plug. Push some grease/paint/glue in to the tiny hole you create to prevent any water ingress.

You can also test for a reading of the sensor at this position. You will then know if your break is inside or outside the engine casing.
Parent - - By HelmetHair Date 01.10.19 23:21 Edited 02.10.19 08:49
After measuring resistance at plug and just outside engine casing, I determined problem was inside casing.
Removed exhaust, drained oil, removed engine sound muff and casing.
Then tested resistance of sensor. Still infinite so that is buggered.
Spare one is showing 245 ohms. Will replace that tomorrow. Hopefully get all back together as well.
Estimated total time for sensor replacement 2 hours. Maybe a little less if you don’t test resistance first, and if your studs are loose on the exhaust.

Oh. And I’ll repair the generator wire too. I’ll add a short extra length rather than try to join the ends up, and test all three wires while I'm at it.
To do this, check the resistance between the three possible "pairs" of yellow wires.
If all the same/closely similar, all is good.

If one is infinite, so will another be, and that will let you pinpoint which wire is causing the issue.
Parent - - By aware Date 02.10.19 04:38
Good job!
Rememver to apply some copper grease to the exhaust studs. Helps in undoing them later.
Parent - By HelmetHair Date 02.10.19 08:50 Edited 02.10.19 22:15
Copper grease-good tip.

I've been restoring a car that's been laid up for 16 years, and the previous owner fastidiously copper greased and correctly torqued *every* nut and bolt.
This has made my repair work hugely simpler.
Parent - By HelmetHair Date 02.10.19 22:20 Edited 03.10.19 10:58
Fitted spare sensor, and while doing so found my spare generator.
I fitted that whole item, including the casing (so as not to have to separate the generator from the casing, or the wire grommet from the casing), and will fix the broken wire on the old generator at some point.

Then drained the oil from the filter, and replaced/refilled.
Replaced exhaust and connected all connections (gen, sensor, lambda probe).
Pressed the button, and woomph! Fired straight in to action. Let it idle a bit then turned off before the CO got me...

Will tidy bits tomorrow, and MOT Friday. Pics and Ebay on Saturday unless someone offers me cash for the bike on here...
Up Topic C1 Information / Repairs - Faults & Fixes / Crank Sensor testing/replacement.

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