New flasher stops working over 2000 rpm

[Brendan W]

The old round aluminium can type two pin flasher started flashing fast - more than twice per second. A tap on the head brought it back to just over one. I got a new plastic box type and it runs fine motor off or at idle but as soon as the revs go up it stops ? The box says 12V but the unit has 12.8V marked on it. Checked the charging system a few days ago and it tops out at 14.4V. The old one is back on and working ok.

[rwnielsen]

There's not enough current passing through it. As your voltage increases with RPM the amperage to light the lamps decreases. You're below the threshold of the flasher..... Not enough load/wattage.

[posplayr]

The flasher can sounds broken and the new plastic sounds like there is a problem as well. A light is a resistive load , even an LED though non linear is still resistive, so the more volts you apply the higher the current.

Something mysterious is happening ; confirm your voltage is going to 14.4 at above 2000 rpm. Also check for broken wires. That means if there is enough current to flab at 12.8v then there will be even more current at 14.1v

[Brendan W]

I spliced the R/R output back into the harness so all these measurements are across the battery terminals. Last week the R/R was wired to the batt +ve and it levelled of at 14.4 approx.
Rest 12.6V Both flashers working , motor stopped
1000 13.4V Both working
1500 13.8V New unit stops unless I switch on headlight which drops voltage
>2000 13.6V Voltage levels off, new unit won't work even if headlight is on
At higher rpm the new unit sometimes gives one flash. If the switch is left on the flashing will start again if the revs are reduced to idle. All six bulbs are working and the four big ones are all the same wattage, 23W I think. They were checked recently. Left and right is the same behaviour.

[Brendan W]

Think I've nailed this one. The revs at which things happen varies a bit but today
1000 rpm unit working
1000-2500 only works if headlight is on
2500-4000 only works if headlight and brake light are on
4000+ no signals no matter what's on.
Opened the connector for the orange wire bundle at the fusebox and gave it a going over with contact cleaner again and now the thing works through the range. Now to figure out why.
Co-incidentally I noticed one end of a new 15A main glass fuse getting hot. Looks like the solder may be broken, the end is loose. Reg output topping off at 14.3V @ 5000 rpm but only 13.6V at battery. Losing 0.3V across the main fuse at idle with ign load only.Hopefully a new fuse will correct this. Reg output is spliced into the original Tee and the ign switch contacts have been cleaned.

[posplayr]

Think I've nailed this one. The revs at which things happen varies a bit but today
1000 rpm unit working
1000-2500 only works if headlight is on
2500-4000 only works if headlight and brake light are on
4000+ no signals no matter what's on.
Opened the connector for the orange wire bundle at the fusebox and gave it a going over with contact cleaner again and now the thing works through the range. Now to figure out why.
Co-incidentally I noticed one end of a new 15A main glass fuse getting hot. Looks like the solder may be broken, the end is loose. Reg output topping off at 14.3V @ 5000 rpm but only 13.6V at battery. Losing 0.3V across the main fuse at idle with ign load only.Hopefully a new fuse will correct this. Reg output is spliced into the original Tee and the ign switch contacts have been cleaned.

The quick test which you seem to have read, is only a sanity check. Once you have established that the basic operation is good I always suggest moving to the Modified Phase A tests to measure your actual voltage drops.

A fuse is unlikely so fix a problem all problems in a fuze box. Depends though on type of fuse box. If your has crimps you need to pull the back off and really clean with naval jelly or similar then treat with contact cleaner.

[Brendan W]

The quick test which you seem to have read, is only a sanity check. Once you have established that the basic operation is good I always suggest moving to the Modified Phase A tests to measure your actual voltage drops.

A fuse is unlikely so fix a problem all problems in a fuze box. Depends though on type of fuse box. If your has crimps you need to pull the back off and really clean with naval jelly or similar then treat with contact cleaner.

Thanks for chipping in again. Good news is the fuse box is now stone cold and the pos lead drop is 0.1V , neg 0.01V.
Bad news is I spoke too soon and this flasher is still dropping out. With no other loads on the slightest increase above idle shuts it down. Lights on just delays it. Downshifting for a turn will switch them off. When I get to the bottom of this it had better be a good story. Looking down from the flasher plug I'm seeing about 20 Ohms left and right. I had figured it should be 3. I've junked the flasher control unit as it doesn't seem to be doing anything useful and PO had a two pin flasher fitted anyway and the handlebar switch is three wire .
Did you ever feel like ripping it all out and rewiring from scratch ?
I was going to post a pic of the bullet connector nest at the switch but there is too much gratuitously offensive stuff on the net already. This isn't just age it's been got at.

[eddie21]

Everyone is wrong, you're just low on blinker fluid!

[Brendan W]

everyone is wrong, you're just low on blinker fluid!

pmsrofl.

[Brendan W]

Update.
I suspected this would happen. I finally replaced the LH bar switch. The old bean can blinker didn't notice, still kept on blinking a little too fast. The new one, black box two prong, now works ok and will blink at it's 65 cps rate irrespective of engine rpm and electrical load.
I have no idea what's going on.