Motor surging

I can’t find the purple wire going up to the steering head, I see there are two bunch of wires coming from the speedo and tachometer which joins into one and then go into the main harness, no connectors.
Now I am not getting the speedo and tachometer to power up at all, even when I wriggle around with the wiring. I guess I will lift the tank off again so I can get a better look around.
 
Try chasing the purple wire backwards from the instruments to under the tank area. You may have to peel the harness back
 
motolink said:
I can’t find the purple wire going up to the steering head, I see there are two bunch of wires coming from the speedo and tachometer which joins into one and then go into the main harness, no connectors.
Now I am not getting the speedo and tachometer to power up at all, even when I wriggle around with the wiring. I guess I will lift the tank off again so I can get a better look around.
Click to expand...

Did you do this yet?

R-III-R Turbo said:
P1690 is from when your clocks died.

With the ignition off, you can set the multimeter to 20v range, put the black probe on the battery -.
Put the red into the purple wire's female pin on the tacho harness plug, you should get 12v. Also agitate your harness while doing this to see if the voltage changes.

Start at the tacho plug and work back to the speedo plug, the heat grips, the accessory clock and the 12v accessory socket plugs.
Finally the underside of fuse #3 both pins.

The method should tell you where along the harness the fault in the purple wire is.
E.g. if all is fine from fuse to heated grips, but the voltage isn't a steady 12.x when you're at the speedo, then you know the fault is between heated grips plug and the speedo plug.

You can open the harness then to physically find the break in the purple.
Click to expand...

It'll narrow down where the break is in the purple wire within the harness, saves you having to split open the entire harness
 
Turbo, no I have not got to it yet, last night I had a bit of a look, will get back onto it on the weekend. I did a search on the forum and one member said he had the same problem after loading a tune and he fixed the problem by loading in another tune, strangely enough my problem started after running in a tune and adjusting TPS. I started the bike and noticed the speedo & tachometer go blank and come back on, went for a ride and it did it again. Then there was some flickering of the lights in the speedo & tachometer now nothing. When the ignition is on I can hear a faint click like relay trying to function but no other start up sounds.
I will find that purple wire and do some testing.
 
I found this photo on the forum, I guess this is the purple wire you are referring too.
8A65573D-C0FB-4ED9-8845-0A7E9A6C2497.jpeg
 
That's the little bugger alright.

That rotten crimp there is where the single purple wire (just above the red circle) joins into the two purple wires that go up to the speedo and tacho. The crimp is about 2' back from the speedo & tacho plugs.

Here is an example of the other crimp, which is about 8" from the fusebox (where the reg/rec plug joins harness), gone rotten;

upload_2019-11-5_22-19-37.png




Diagram to illustrate the purple wire layout in the Roadster harness;

upload_2019-11-5_22-42-5.png
 
3F1DF867-6AD6-486C-97D5-2009687F5359.jpeg
Well I think I have found where the problem is, like the photo says when I squeeze the harness where the X is the speedo & tacho will power up every time. I can feel the wiring connectors in the harness. On the weekend I will strip the harness back and hopefully all will be revealed.
 
Last edited:

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