VintageVmax.com

Well we got 6-8 inches of snow here and I took the vmax out for a short ride as I did not get to ride it last year at all, after rideing for a shot time I noticed that the headlight would drop out at low speed,I run a digitron on it and it gets its tach pulse from the lighting circuit and it would go blank when the headlight went out,my question is could a faulty voltage regulator cause this? it did come back on and start working again so all is well but I need to figure it out,thanks.

What sled? May not have enough output on the lighting coil to run both at low rpm. Added handle bar warmers to early 540's caused some issues like that. Your Digitron may require more juice than what's available. Later 540's (85? and up) had an extra coil just for warmers (yellow/black). Yellow and Yellow/Black stripe out of the stator as opposed to just yellow on earlier ones.

opsled

Yes mine is a 1986 so it has the extra coil for the handwarmers, the weird thing is it worked for awile and then stopped working and the started working again.

Been a very long time since we used Digitron stuff, but thought it was self powered ( battery). Sounds like a short to me, had the tail light wire wear through on my SRV under the seat which caused pretty much the same problem. Might also be simply a dirty connection in one of the plugs. I take a look there first

Even the newer with the seperate coil have limited total wattage output from the stator especially at low rpm. Tyler (Tyler440) uses a remote rechargeable battery to power his digital EGT gauges.

viewtopic.php?f=2&t=1529
-Head light dims when braking
Use a Red LED taillight bulb http://www.bluhmenterprises.com/product ... gory_id=29

I have 4 sleds with MyChrons on them including e boxes, all run on the 6 internal AAA batteries all season.I don't ride alot but even in karts they go most of the season on the small batteries. In the early 90's we ran tripple display Digitrons and they ran forever on internal batteries The big EVO4 system on the race sled does use a 12v motorcycle battery but its not very big and also powers a total loss ign system.
I'm still bettin short or lose conection

actually my EGT's are powered by the battery because withOUT the headlight on (lit) they cut out just above idle and dont come back on until it idles back down. almost like they are getting too much voltage. the OP hasn't commented since bob pointed out that the digitron gauges are most likely battery powered. im guessing his are battery powered to.

i think the real problem here is with signal and not power, but i still dont know the answer.

when looking for weird light related issue the first place i got is under the seat. i have spent many hours trying to find a loose wire in a headlight, only to have to ride back home in the dark.

My digitron is a dt53s and does not use batterys, I have never had a yamaha voltage regulator go bad so I dont know what the symptems are, I have seen other makes go bad and the lights all but go out, I am taped in right at the magneto so it is not the headlight switch unless it is shorting out and that I may need to look at,thanks to all.

ok so its getting both signal and power from the headlight.

definitely check the wire under the seat, its almost certainly your problem