Anyone know motorbike electrics?

[swee'pea99]

Never had this one before: both front indicators working - but very fast - both rear indicators not working at all. Checked the bulbs - all look fine. Also swapped the rear ones to the front & vice-versa: made no difference. Any ideas very welcome.

 

[aoj]

Never had this one before: both front indicators working - but very fast - both rear indicators not working at all. Checked the bulbs - all look fine. Also swapped the rear ones to the front & vice-versa: made no difference. Any ideas very welcome.

Indicator relay most likely

 

[swee'pea99]

Hmmm. Thanks. Easy fix or take it to The Man?

 

[jazzkat]

If the indicators flash faster, if I remember rightly, it's because the relay is getting too much juice, because the rears aren't flashing too. It seems weird that both rears aren't working. Do they have a common earth? There's not much to a relay and I would expect it to work or not!
Check the wiring first - good connections/earth etc (maybe run another wire back as an extra earth) if it's not that try a new relay.
After that....gawd knows!

 

[swee'pea99]

Yeah, I thought it was a bit odd that both rears were out. Do they have a common earth? Dunno. I shall have a good look at the wiring diagram in my old Haynes manual and see if I can make sense of it. Thanks.

 

[Spinney]

About 20 years ago, small Honda with a 6V battery, had to run an extra wire from the rear indicators to get them to work - earthing through the frame seemed to be rather dodgy, esp. with 6V systems.

 

[DRHysted]

As said above first things to check are bad earth and relay. Relay is relatively easy if you can find it and have basic knowledge.

 

[compo]

Check your earthing on the rear lights. I would suggest the problem isn't the relay as it is working, ie, flashing the front. The indicators may be earthed via a wire or by a metal to metal contact or both. You don't say what bike it is.

 

[swee'pea99]

Thanks. I think the attached shows that both (29 & 31) share the same earth (in the vicinity of 17) - along with the rear light. Would that be right? It's an ancient BMW R65, by the way.

 

[compo]

Could well be. Just follow the brown wire and see where it attaches to the frame. A multimeter makes short work of continuity testing. On older bikes corrosion is the biggest bugbear. Clean everything, all connections, and make sure all the plugs and sockets are fastened securely.

 

[swee'pea99]

Since all earth leads seemed to go via the rear lights, I took the red plastic off and cleaned up the contacts with emery paper...which is when I noticed that one of the bulbs - I'm not sure whether it's the brake or the rear - is distinctly discoloured, and , on a closer inspection, I'm pretty sure the filament's gone. So this could be BMW's way of warning you that your rear lights are not right. First thing to do is get new bulbs for the rear and see if that helps. Thanks all.

 

[swee'pea99]

Update: well, that didn't work! Changed both bulbs, same difference. Googling has revealed an oddity with the R65, which could account for some other problems I've had with it (http://www.cafematty.com/tag/electrical-system/) so I think I'm at the point where I hand it over to someone who knows what they're doing, and get the whole lot sorted out at once. Thanks all.

 

[jazzkat]

I hope it's an easy (as in cheap) fix for you!
Good luck

 

[swee'pea99]

Thanks.

 

[Deleted member 1258]

Many years ago a CZ175, I overhauled the front forks and whilst doing that replaced the headlight mountings, then had to rub a small amount of paint of the new mountings to make the indicators work properly, the front indicators were bolted to the mountings.