facebook1 youtube1 twitter1 instagram google plus linkedin1 pinterest1

logosmallNOTICE:  If you are not a free registered member of the site, you will not see the photos in the forum, and you won't be able to access our premium member content. Please consider joining our community!

Welcome, Guest
Username: Password: Remember me
  • Page:
  • 1

TOPIC: Testing the headlight

Testing the headlight 07 Apr 2018 09:03 #1

  • 75SDDT400
  • 75SDDT400's Avatar Topic Author
  • Offline
  • Mini Enduro
  • Mini Enduro
  • Posts: 11
  • Likes received: 5
Hello all. So I have a quick question regarding the headlight on my 75 DT400. I'm in the process of bringing this bike back from the dead. I noticed today that my headlight is blown ( can see pieces of the filament inside).

Anyways, I have a new one on the way, but wanted to know if there's a way to test the headlight out of the bike, i.e directly from a battery. I know the headlight is run off of a/c voltage when installed on the bike, so I'm assuming the only true way to test it is installed with the bike running.

Can anyone confirm this?

Thank you.

Please Log in or Create an account to join the conversation.

Testing the headlight 07 Apr 2018 09:32 #2

  • MarkT
  • MarkT's Avatar
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 4615
  • Likes received: 2100
Old fashioned incandescent (glowing filament) bulbs do not care one bit if they are run on AC or DC power. The 6 volt battery on the bike can be used to test.

You might consider installing a 6VAC voltage regulator... original Yamaha (came standard in 1976) or the one DEET recommends.

Here's a link to the "how to" for the Yamaha type:

yamaha-enduros.com/index.php/workshop/se...e-voltage-regulators

Please Log in or Create an account to join the conversation.

1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250

Testing the headlight 07 Apr 2018 09:44 #3

  • Makotosun
  • Makotosun's Avatar
  • Offline
  • Site Administrator
  • Site Administrator
  • Admin is in the House!
  • Posts: 6497
  • Likes received: 2347
+1 on a regulator.. the OEM bulbs are getting hard to find or are very expensive. You can aonvert to a 5 3/4” H4 conversion shell, then user 6 volt H4 bulbs which seem more available and are less expensive,

Please Log in or Create an account to join the conversation.

No Good Story ever started with a Salad . . .

Testing the headlight 15 Apr 2018 16:54 #4

  • 75SDDT400
  • 75SDDT400's Avatar Topic Author
  • Offline
  • Mini Enduro
  • Mini Enduro
  • Posts: 11
  • Likes received: 5
Thank you for the reply guys. I was able to find a new headlight through Napa of all places, so I will be trying it shortly.
Every bulb on this bike is blown so I'm certainly going to look into a regulator. Hopefully I can find an inexpensive OE Yamaha one, as they seem to be the best option.

Please Log in or Create an account to join the conversation.

Testing the headlight 16 Apr 2018 19:25 #5

  • MarkT
  • MarkT's Avatar
  • Offline
  • Site Contributor
  • Site Contributor
  • Posts: 4615
  • Likes received: 2100
price on this one isn't too bad

Please Log in or Create an account to join the conversation.

1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
  • Page:
  • 1
Moderators: VinnieDEETyamadminDmanEnduronutMakotosunDevinJames Hart