Reason for speedometer bulbs burning out?

[oochaDog]

Hey Big Brains I'm looking for direction.

I'm working on a 94 Wombat, added new Speedometer and high beam socket harness and new bulbs. When the bike is not running bulbs work fine. I then started up the bike and bulbs were working fine while warming up the bike. I rev'd the bike a couple times then shut it down. Shortly after shutdown I noticed both bulbs were burnt out. I do have a 15A/35W fuse on the positive wire off the battery.

Before I burn out more bulbs diagnosing this issue I'd like to get some pointers on what to look for.

Thanks so much!
Jay

[thrownchain]

Do you have a battery in the system ?

[olddogs]

The 94 did not come with a voltage regulator. Later models did. When the amperage increases with engine rpms, it burns out the bulbs filament. The small bulbs go first, then the headlight and taillight eventually burn out. You can see this happening if you watch the headlight get brighter as the engine revs. There are a couple previous posts on this site about wiring in a voltage regulator. I would do it before you fry the headlight, they are getting harder to find.

[oochaDog]

@thrownchain - Yep have battery in system.

[oochaDog]

@olddogs - I'll have a look for voltage regulator. Thanks.

[viclioce]

I may have a spare voltage regulator for you! Let me know if you’re interested. It’s from a Road Toad but should work for you. All you would need to do is wire it in correctly. Can’t advise you on that, as I’m not familiar with the Model 94/94A wiring. But I’m sure someone here can advise you! Victor

[oochaDog]

Victor thank you so much for the offer but earlier today I picked one up on Ebay.

[rlkarren]

The VR is attached to the green wire from the key switch, you may have to change one of the connectors to a male type.

The green wire from the key switch travels all the way to the emergency switch inside the headlight bucket. You can attach the VR anywhere along this wire. Then. make sure you ground the white wire and the aluminum tang to the bike.

I made this diagram a few years ago from the Model94A diagram. I removed all the turn signal wiring so it was more specific to the Model 94. You can see how I added the VR in the lower right.

$0.02

Roger

PS I have a bigger version, I'll see if I can find it.

[oochaDog]

Thanks Roger!