Turn signal problem

I'm sure this is simple question for you electrical gurus out there, but I can't figure it out...

On my '76 Z750 B1, my turn signals work fine below 3,500 rpm, but above that they start blinking faster and faster. I'm talking crazy fast, almost to the point where they stay lit (they don't though). My initial thought was that the charging system was generating too much juice, but my multimeter only reads ~12.5 @ 4,000. So it's just barely charging (yet an other issue to deal with). I even replaced the regulator, with a NOS one I bought a while ago.

What would cause this?

Have you tried a new turn signal flasher/relay? (the metal can type)or looked at the related wiring for shorts/rubbing to the frame.

No, but the flasher was a brand new one from Z1E . The old one didn't work at all. I don't have a spare one now (well I could try one from the MkII), but I figured a flasher either works or not. I guess that is a wrong assumption?

Haven't done a very thorough wiring check yet. Wouldn't such a problem be constant though? As in not dependant on engine RPM.

If all the bulbs light, then it can really only be the flasher. They are real simple device, but a real pain sometimes too. I bought a new one at an auto parts store and it didn't work, went to an auto parts store that was a little extra money and it worked fine. If you can find one made for trailer towing applications on a car/truck these are the best bet as they don't rely on load and will always flash the same rate. The ones Z1 sell appear to be Emgo, so probably Chinese so could have got a bad new one easily.

Have you installed any new bulbs lately?
It has been reported that the stock flasher doesn't work right w modern bulbs. One fix, as suggested by RonKZ650, is to get a heavy duty trailer flasher.

No new bulbs. I'll see if I can get a new heavy duty flasher tomorrow. Thanks for all the advise.

kzrider wrote:

I'm sure this is simple question for you electrical gurus out there, but I can't figure it out...

On my '76 Z750 B1, my turn signals work fine below 3,500 rpm, but above that they start blinking faster and faster. I'm talking crazy fast, almost to the point where they stay lit (they don't though). My initial thought was that the charging system was generating too much juice, but my multimeter only reads ~12.5 @ 4,000. So it's just barely charging (yet an other issue to deal with). I even replaced the regulator, with a NOS one I bought a while ago.

What would cause this?

12.5V @ 4k RPM sounds like the alternator is not charging or charging very little. The field winding (stator) may be hosed or the reg/rectifier assembly may not be the right one for the system.

As for the blinker mystery: I would say change the flasher unit and also make sure the bulbs are good. If you blow a bulb thr flasher will blink faster.

kzrider wrote:

No, but the flasher was a brand new one from Z1E . The old one didn't work at all. I don't have a spare one now (well I could try one from the MkII), but I figured a flasher either works or not. I guess that is a wrong assumption?

A regular flasher is a bimetallic strip that curls when it gets hot from the current flowing through it. So, it has to be matched to the load current presented by the bulbs. On a KZ750B, you are supposed to have two 1157 bulbs in parallel that draw about 2A each at 12V. As the 12V changes, the current draw changes a little. Check and make sure you have the right type bulbs and that both are lighting.