Gremlins

[Ian_B]

Well it appears that some electrical gremlins have taken up residence. The bike was started for the first time today and fired up after only a couple of kicks but the good news was limited. All appears well until the bike is revved when the temperature gauge reading drops and neutral light dims. As the revs fall the temperature goes back up and the light brightens again. Deep joy.

[ScottaKR]

Yeah, gremlins seem to love hanging out anywhere there's wiring.
Go over all your earth connections to make sure they're all good and clean, and also check the charge voltage to make sure the stator is ok.
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KR250 Tandem Twin (Naked)
KR1 Red/White
KR1S Track Bike (has been put on hold for now)
ZXR750 H1 (Winter project)

[Bert]

I agree with Scott
Sounds like a dodgy earth to me

Bert

[Ian_B]

Both the earth near the battery and the one near the regulator appear good and clean. The charge voltage is fine until around 3000rpm when it starts to drop as the revs rise and then rises as the revs fall. Looked at the voltage at the oil light on the dash and it drops by 4 volts as the revs rise and then returns to normal as the revs drops to idle.

[JanBros]

change the rergulator
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my brain is hangin' upside down

[ScottaKR]

Have you made sure the earths are both making metal to metal contact? I ask this because all that beautiful paintwork on the frame can make a really good insulator. I'd disconnect them both and make sure the threads in the holes are clean of paint by running a thread tap "or one of those bolts with the slot cut in the end of the thread" through them a few times just to be sure.
You could try adding an (temporary) extra earth point at each one (just piggy-back it from the normal one to another bolt hole close by) to see if that makes any difference just to be sure.
_________________
KR250 Tandem Twin (Naked)
KR1 Red/White
KR1S Track Bike (has been put on hold for now)
ZXR750 H1 (Winter project)

[Ian_B]

Thanks for the pointers.

I re-tapped the holes after the frame was repainted and also had small areas around the two earths stripped back to bare metal so the wiring lugs sat directly on the frame. Tried other points on the frame all with the same effect. Looks like I need to try another regulator as Jan suggested.

[Ian_B]

I tried a replacement rectifier/regulator today that Scott kindly provided. Unfortunately, the gremlins remain exactly as before. Any other thoughts as to the next line of investigation?

Thanks,

Ian

[ScottaKR]

Glad to hear it arrived safely.
Even though youve checked all your earth points, it still sounds like an earthing issue to me. May be worth checking the resistance between the 2 earth wires when they're disconnected from the frame as one of them could be damaged. I'll admit I'm grasping at straws here though.
_________________
KR250 Tandem Twin (Naked)
KR1 Red/White
KR1S Track Bike (has been put on hold for now)
ZXR750 H1 (Winter project)

[Ian_B]

Good news today, the gremlins have been banished!

Spent a while checking all the wiring against the diagram in the manual and didn't find any problems but it dawned on me that the only items playing up were the ones fed from sensors or switches on the engine itself. Made a jumper from the engine to the earth point near the regulator and all issues were resolved.

[Charles]

that's good news

[ScottaKR]

Great to hear you got it sorted. Good bit of investigative work youve done to come up with that solution.
_________________
KR250 Tandem Twin (Naked)
KR1 Red/White
KR1S Track Bike (has been put on hold for now)
ZXR750 H1 (Winter project)