1974 GT380 HEADLIGHT

[bondspyguy]

Hi Guys
I blew the sealed beam headlight on my 74 gt380 and am having a job finding a replacement...Does anyone know what other models will fit??....thanks to anyone that can help

cheers stu

[jabcb]

You can upgrade to a H4 halogen headlight from a GS-L series bike.

The headlight is NLA but is often available at a reasonable price via eBay.
Will also need the GS-L series headlight rim + misc parts.

For more info see:
viewtopic.php?f=2&t=9972&hilit=gt380+headlight&start=12
That topic includes pics of the conversion on my T500.

[Coyote]

You will never find an OEM replacement lamp Believe me, I checked all over the earth for one about 4 years ago. No one could supply it in this country or any other country on the planet. I bought several used ones off ebay and they were all junk. Peeling off reflector material inside the lamp. I think I bought about 7 before I found one that was acceptable.
If you find one om ebay, be sure to ask about the integrity of the reflector before you buy. Best bet (and for your own sanity) is to do the conversion mentioned in the previous post. Forget the lamp. There aren't any.

[Barry S.]

A 380 doesn't make enough juice to run a halogen bulb. I used to have one with a Bosch headlight lens that took a replaceable bulb and I put a halogen bulb in it and it would draw so much power the bike would foul a plug.

[jabcb]

The GT380 has the same alternator as the GT550.
They have Nippon Denso or Kokusan alternators.
The alternator performance curves are here: http://www.ozebook.com/compendium/suzi/suzidata1.htm

Alternators of that era don't produce much output at low rpm. A lot of bikes didn't start charging the battery till something like 2k rpm.

Stock, the GT550 has a brighter headlight & a larger battery.
The GT550's larger battery is more capable of dealing with low rpm alternator performance.

How well the GT380 handles a brighter headlight depends on your situation.
Which alternator you have. (Nippon Denso provides a lot more low rpm output than the Kokusan.)
How much time you spend at low rpm.
What shape your alternator is in.
The condition & type of battery.

H4 halogens are available in lower wattages: 45/45W & 35/35W.

The T500 has a pretty meager alternator & a small battery.
They also tend to not run well with a weak battery.
I have a 45/45W H4 in my T500 & have not had problems.

An H4 halogen headlight is brighter that the stock GT380 headlight when the bulb wattages are the same.
You just need to pick a bulb wattage that works for you.

[Barry S.]

My 380 had the Kokusan and according to the chart made 15 amps while the Denso made close to 30. Mine didn't work.

[jabcb]

I made two changes to my T500 that I didn't think of mentioning.
Upgraded to a modern rectifier/regulator & switched to an AGM battery.
Modern rectifier/regulators are more efficient & an AGM battery discharges between rides much more slowly.

Late GT380s had a 40/30W headlight. The GT550/GT750 had a 50/40W headlight.

If you upgraded to a 55/60W H4 headlight & kept the stock conventional battery, then I can see that you might have problems depending on what riding you do.

A 35/35W H4 would be a pretty safe bet for the GT380 since the wattage is nearly the same as a stock headlight.

[bondspyguy]

will any of the other gt models fit or are they bigger in size ?? there are gt550 250 and 750 for sale on ebay also a t500 just an thought i have asked the sellers but had no reply....thanks for the help guys.i have totally restored this thing and at a stop now just because the lamp blew lol

cheers stu

[jabcb]

Your 74 GT380 came with a 35/25W headlight with part # 35121-36160
For later model year, the headlight was increased to 40/30W with part # 35121-33630

The headlight was also used on the GT185, GT250 & T500.

[bondspyguy]

Thanks for your great help jabcb ....there is a gt185 for sale i will get that one

[Coyote]

35121-36160 is the correct part, but that is the one that is extinct. I did a lot of research back then and that PN is not to be had ---- anywhere. I believe it to be the the only lamp with the goofy 3 hole mount top and bottom. Only 2 are used. Never could figure out why there were 6. Other lamps will not fit the bucket - even though the others are the same diameter.
And yes, the 550 and 750 lamps are larger than the 380.

[bondspyguy]

well guys i must be the luckiest SOB GOING i found a nos headlight at FS-WORLDWIDE http://www.fs-worldwide.com" onclick="window.open(this.href);return false;
instead of looking for gt380 model i looked for Koito headlights paid $55 inc shipping a bargain for a brand new one
i am amazed as i have no luck.....IF I FELL IN A BARREL OF TITS I WOULD COME OUT SUCKING MY THUMB ......


CHEERS STU

[Weirdbeard1000]

IF I FELL IN A BARREL OF TITS I WOULD COME OUT SUCKING MY THUMB ......

Effing hysterical!

[Coyote]

Let us know when you get it. I hope it has the correct mounting ears. Did you see a pic?

[bondspyguy]

i got the lamp and yes it was the correct one worked great

stu