1982 GS300L Headlight

[rurfen]

Howdy all!

A short background: Last fall I bought a mostly pristine 1982 GS300L with only 6800 miles on it, stored for 32 years in a SoCal garage (started right up with new oil, battery, and gas). The GS300L seems a bit like the red-headed stepchild of the GS series as it was only made for a few years, and there doesn't seem to be a whole lot of model-specific information on it.

Should I just treat my bike as a 450 when searching the forum?

The bike still has the original headlamp assembly with a 40W/45W 6.25" sealed beam (approximate measurement). The low beam has burned out, and finding sealed beams in the appropriate size/wattage seems to be nigh impossible. I need to have both low- and high-beam capability, but am unsure of the consequences of simply replacing the headlight assembly with something like this Emgo H4 assembly (7", 12V, 60W/55W).

Would switching to this higher wattage lamp overdraw the electrical system on the 300?


Thanks for your time and opinions, and let me know if I should have posted in another forum.

 

[Grimly]

Get a 7" H4 lamp assembly and use an LED bulb. 20W load won't bother your alternator, even if it's a weeny one. As an '82 bike, it likely has an 18-pole alternator anyway, and probably shares the same parts as its larger brothers, like the 450, 500, 650, etc.
The usual caveats about shunt reg-recs and dirty/corroded connections apply, of course.
http://www.cyclopsadventuresports.com/led-headlight-bulbs.html as a source of trusted lights. You can find cheaper on the 'bay of course.

 

[rurfen]

Thanks Grimly! I'll report back once I've got the new assembly installed

 

[Grimly]

Thanks Grimly! I'll report back once I've got the new assembly installed

Ok, just check your charging voltages as they are right now - do the quick series tests and see what's happening. If it all checks out, you could fit the H4 light and then run it for a while to see how things hold up. I strongly suspect your charging system will cope fine with the standard halogen bulb, even with the standard shunt-type reg/rec. There were plenty of 250s / 300s back in the day that had an H4 lamp fitted as a routine upgrade with no worries.

Otoh; just to clarify - if you do go the LED route, it would definitely be worth your while to fit a series regulator and do away with the shunt type that will be on that bike as standard. You may as well do that once and for all and lay the charging system ghost to rest before it even gets up to haunt you.
The only downside to the LED light is that the reduced load (and better lighting), while a good thing on its own, will put extra strain on the stator windings, because of the way the shunt regulator works - any unused load is shunted back through the windings, adding to the heat within them. A series reg doesn't do that, and the windings seem to last forever (so far, anyway).

 

[Steve]

If you go with the 7" headlight, be sure to get the mounting ears, too. :-k

The bucket for the 7" light will obviously be bigger than what is on there now, which will spread the ears out. You might not think that is much of a problem, but the ends that actually hold the headlight will not be parallel with the bucket and the turn signals will not be pointing straight ahead.

.

 

[rurfen]

Update time! I have the the 7" headlight and mounting arms and set about to replace the assembly yesterday. However, I did not notice until now that the original headlamp mounting arms are welded to the forks instead being being bolted on. If you made this replacement, did you remove the welded on arms? Also, the new headlight mounting brackets don't have a spot to mount the turn signals. I feel like a complete novice (which I apparently am...) for not noticing that earlier.

I'm still in the thinking stage, but I'm thinking I might just drill an appropriately sized hole in the new arms to mount the turn signals, make or find a rubber/plastic grommet to protect the wires from the edge of the hole, and mount the turn signals that way. Does that make sense to do? I'm at the office right now, but when I get back home I'll take some photos and make a quick sketch of what I'm describing here.

 

[Steve]

They are NOT welded on. You will need to remove the front wheel and fender, then loosen the clamps for the fork legs. The headlight mounting ear is trapped between the upper and lower triple clamp and held by the fork leg. Slide one fork leg down, pull the old mount out install the new one. Repeat for other side. Install fender and wheel.

While you have the forks loose, you might consider changing the fork oil.

Since you will have the caps off the fork tubes to change the oil, you might want to consider replacing the springs, too.

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