Hi! I have a question. The bike is a 1994 K1100LT.

For a bit of background, last evening I have done a relay upgrade to my headlight, using 18A automotive relays with a 15A automotive fuse (in the relay compartment below the tank), all connected and properly isolated and secured, etc.

Now for the question proper - can I run 100W bulbs in there? As I've read on this forum (and on motobrick), some users say it's completely fine and problem-free. Despite that, I still am not entirely sure about going forward with those higher-wattage bulbs.

My main concern is heat. Will the OEM BMW H4 holding bracket survive the higher temperatures? What about the reflector itself, of the glass up front? I've read horror stories of headlight glass breaking when splashed with water because of the added heat of a 100W bulb.

I'd just like to hear from more experienced K-bike owners regarding the headlight assembly quality and resilience to heat. Thanks in advance.

EDIT: 
Reading up on the subject, and thinking about it, I probably won't put a 100W bulb in my bike - the heat issues and legality of it. Are there any other reliable ways to get a proper quantity of light out of a headlight? Does simply buying quality lightbulbs help significantly?

I've not used the higher wattage bulbs myself, but I recall from past discussions that the headlight assembly is okay with a higher wattage bulb. 

The problem is the plastic connector on the wiring harness.  It is necessary to replace it with a ceramic body connector to prevent the additional heat from melting the plastic.

Point-Seven-five wrote:The problem is the plastic connector on the wiring harness.  It is necessary to replace it with a ceramic body connector to prevent the additional heat from melting the plastic.

I haven't thought of the connector, thanks!

A 100 watt bulb will use 66% more power, most of that extra power will be turned into hear and a little of it into light, it is not worth the risks to the bikes electrics, and it is illegal in most countries.

I've run them before, the headlight will cope fine.  Its the switches that are the problem and as you've added relays they will be fine. Upgrading the wiring plug to a ceramic one and adding a heavier earth wire wouldnt hurt either.

Today a better answer is probably a quality LED H4 bulb.

Al

If you put a bike running a 60watt bulb and a bike running a 100watt bulb side-by-side, you might just notice the difference. It's not worth the effort. The real problem is deterioration of the reflector. Back in the Seventies and Eighties a headlamp reflector lost 60% of its reflectivity after as little as four years.

Yes, we're all riding round with buggered headlights!

AL-58 wrote:Today a better answer is probably a quality LED H4 bulb.

Al

Is here an LED H4 replacement with the proper dispersion pattern available today?  I have been following them for a year or so now, and still haven't seen a good(or legal) LED retrofit yet.

If you want conspicuity in daylight and some additional downrange illumination at night a couple LED driving lights can be a good investment.

I am using these lights on all three of my bricks:

https://www.ebay.com/itm/WEISIJI-Motorcycle-Driving-Lights-10W-2inch-LED-Work-Light-Fog-Lights-for-Harley/162731463111?epid=2151918589&hash=item25e38d11c7:g:c5gAAOSwCMFZ99-3&vxp=mtr

The pattern of the spot light is tight enough so that oncoming drivers don't flash me at night, and they are like having two arc welders going on the front of your bike in the daylight.  Drivers cannot avoid noticing them in the daytime.

AL-58 wrote:AL-58
I've run them before, the headlight will cope fine.  Its the switches that are the problem and as you've added relays they will be fine. Upgrading the wiring plug to a ceramic one and adding a heavier earth wire wouldnt hurt either.

Today a better answer is probably a quality LED H4 bulb.

I don't want a LED bulb mainly because, as far as I know, there is no LED bulb that's to the H4 spec - it'll shine wherever it wants and blind people. And a proper LED conversion kit is most probably not worth the money.

Dai wrote:Dai

If you put a bike running a 60watt bulb and a bike running a 100watt bulb side-by-side, you might just notice the difference. It's not worth the effort. The real problem is deterioration of the reflector. Back in the Seventies and Eighties a headlamp reflector lost 60% of its reflectivity after as little as four years.

Yes, we're all riding round with buggered headlights!  

Good point - in that case, are there any quality aftermarket replacement reflectors for the K bikes? Or should I buy a new-ish OEM one and observe as it fails?

...or maybe I just should not really care about it that much and just leave the reflector as-is 

Point-Seven-five wrote:If you want conspicuity in daylight and some additional downrange illumination at night a couple LED driving lights can be a good investment.

I am using these lights on all three of my bricks:

(link)

The pattern of the spot light is tight enough so that oncoming drivers don't flash me at night, and they are like having two arc welders going on the front of your bike in the daylight.  Drivers cannot avoid noticing them in the daytime.

I probably wouldn't like the look of it, I'm aiming for an as-stock-as-possible look for my bike. But then again, for some reason I have the holes for police lights in the front, which would be a nice and easy location for those lights.




Reading up on the subject, and thinking about it, I probably won't put a 100W bulb in my bike - the heat issues and legality of it. Are there any other reliable ways to get a proper quantity of light out of a headlight? Does simply buying quality lightbulbs help significantly?

Thank you all for answering and helping out!

A few owners have improve their stock headlights by cleaning them internally. Filling with glass cleaner or detergent and water swilling it around. Rinse with water then push rag in and poke it around with a stick. You might have to do it a couple of times.
Regards Martin.

Actually just got this Youtube link in an email from The Retrofit Source.  They are comparing H4 halogen vs. LED vs. HID vs Retrofit projector.  This might answer some of your concerns:

https://www.youtube.com/watch?v=Na5xTO8Vigw

MartinW wrote:A few owners have improve their stock headlights by cleaning them internally. Filling with glass cleaner or detergent and water swilling it around. Rinse with water then push rag in and poke it around with a stick. You might have to do it a couple of times.
Regards Martin.

On a K (RT/RS/LT/K1) its even easier than that.  The glass is held on by four metal clips, just remove them carefully and clean the inside of the lens and the reflector then reassemble.  Its quite easy.

Al

New old stock will have deteriorated just as badly. I did once have a hope-over-knowledge moment and bought a NOS reflector - absolutely no difference in light output or beam dispersal. Whatever you do, DO NOT USE A METAL POLISH ON THE REFLECTOR. It's an extremely thin metal deposit and you'll rub through it on the first touch. Soap, water and a soft cloth only.

In the end, I solved my light problem by fitting a 7" round brand-new Cibie in the fairing (post 78 here: https://www.k100-forum.com/t10428p50-comberjohn-s-ghost). However, that did involve making new brackets and welding them to the fairing spider. The 'faired-in' area around the headlight is 4mm thick plastic card (Plastikard). I didn't have to make any mods to the fairing itself.

AL-58 wrote: On a K (RT/RS/LT/K1) its even easier than that.  The glass is held on by four metal clips, just remove them carefully

Could be useful to have a new gasket at hand, before disassembling.

AL-58 wrote:

MartinW wrote:A few owners have improve their stock headlights by cleaning them internally. Filling with glass cleaner or detergent and water swilling it around. Rinse with water then push rag in and poke it around with a stick. You might have to do it a couple of times.
Regards Martin.

On a K (RT/RS/LT/K1) its even easier than that.  The glass is held on by four metal clips, just remove them carefully and clean the inside of the lens and the reflector then reassemble.  Its quite easy.

Al

Might be a good idea to do that.

Inge K. wrote:Could be useful to have a new gasket at hand, before disassembling.

OEM headlight gaskets are rather cheap, so I'll do that.

Dai wrote:New old stock will have deteriorated just as badly. I did once have a hope-over-knowledge moment and bought a NOS reflector - absolutely no difference in light output or beam dispersal. Whatever you do, DO NOT USE A METAL POLISH ON THE REFLECTOR. It's an extremely thin metal deposit and you'll rub through it on the first touch. Soap, water and a soft cloth only.

In the end, I solved my light problem by fitting a 7" round brand-new Cibie in the fairing (post 78 here: (link)). However, that did involve making new brackets and welding them to the fairing spider. The 'faired-in' area around the headlight is 4mm thick plastic card (Plastikard). I didn't have to make any mods to the fairing itself.

Since buying a reflector probably won't improve the light, I'll clean it out. I'll take off the front glass and carefully clean it, replacing the gasket in the process. 

That round headlight sounds like a good idea light-wise, but I want the bike as stock as possible.

robmack wrote:Actually just got this YouTube link in an email from The Retrofit Source.  They are comparing H4 halogen vs. LED vs. HID vs Retrofit projector.  This might answer some of your concerns.

That retrofit projector gives off such a sharp and beautiful light! It wouldn't work with the K's headlight glass though, unless I found a clear one. 


Thanks for helping out! Right now my plan is to just carefully clean the reflector with soap, and simply buy some quality brand H4 bulbs to see if, by chance, they can improve my light output significantly.

I am not sure if cleaning the reflector is a good idea.  The plating is very sensitive to abrasion, and even a soft microfiber cloth will leave a haze that reduces the reflectivity.  I just tried cleaning one of my headlights and am not pleased with the result.  Best to avoid all contact with the reflector and concentrate on cleaning the inside of the glass lens.

Regarding the LED driving lights, I have them mounted on the "chin" of the fairing under the headlight.  They are fairly inconspicuous there and don't create any glare to effect my night vision.

My experience with fitting a HID bulb and ballast system was less than satisfactory on 2 fronts. If your bulb and/or ballast blows, then it is far more difficult doing an at night on-the-road repair compared to changing a standard H4 bulb. The kit I fitted had a disconcerting problem that when you switched to high beam, there was a 1-2 second period of total darkness before the bulb lit up. It may be that this delay problem has been resolved by more recent HID kits as mine was fitted about 7-8 years ago. The switching delay for me represented a real safety risk.
Ceramic bulb connectors are a great easy upgrade from plastic and are not at all expensive these days.
The loss of reflector efficiency over time is problematic. In the very early days headlight reflectors were made of silver plating on either copper or brass sheet metal and could be cleaned using silver polish. Those days are long gone and any cleaning of modern reflectors risks damaging the reflective coating. Years ago I heard from a Citroen specialist (degraded headlight reflectors was a common problem and new Citroen headlamps were mega expensive) that a reflective powder could be applied using a vacuum process to refurbish the reflector (I wonder if this is not some powder coating process). There must be some specialists out there who can perform high quality reflective recoating. Anyone able to shed some light on this?

A variation on point seven fives lights. There were two types, a flood and a spot I went for the flood as I wanted a day/night running light. The addition of this light has helped greatly with the visibility of the bike. I got it off Ebay for $16.00 Au. There were heaps being sold by one particular vendor, with a low starting price. Most were selling for  around $60.00 + Au.  I just kept on putting $20.00 Au max bids.
Regards Regards Martin.

RedRock, Since most modern lights have plastic bodies, traditional plating methods don't work all that well on them, and that is not to mention the problems of handling the highly toxic plating solutions.

The modern process is vacuum deposition.  The part is put into a chamber where a high vacuum is drawn to get all the air out.  Then an electrode is energized which causes atoms to leave.  With no molecules of air in the chamber, the atoms of the electrode can travel to the part where they attach themselves to the plastic.  Since the process can be rather time consuming, the thinnest coating that works is what they shoot for.  That doesn't leave much material for polishing or cleaning.  Also, my understanding is that these coatings are very soft.

redrockmania wrote:My experience with fitting a HID bulb and ballast system was less than satisfactory on 2 fronts. ... The kit I fitted had a disconcerting problem that when you switched to high beam, there was a 1-2 second period of total darkness before the bulb lit up.

If this was a straight swap H4 bulb for HID bulb, then I can see this being a problem. HIDs take some seconds to ignite and warm up to full intensity so switching them on the fly doesn't work the same as halogen.

The proper method if retrofitting HID to an H4 housing involves installing a projector system. The projector has a lens to focus the light in the correct pattern, as well as having a solenoid operated shutter to flip between low beam (dip beam) and high beam. That means the HID bulb never turns off. It also accounts for the fantastically sharp cutoff pattern one sees in a projector system.

robmack wrote:

redrockmania wrote:My experience with fitting a HID bulb and ballast system was less than satisfactory on 2 fronts. ... The kit I fitted had a disconcerting problem that when you switched to high beam, there was a 1-2 second period of total darkness before the bulb lit up.

If this was a straight swap H4 bulb for HID bulb, then I can see this being a problem.  HIDs take some seconds to ignite and warm up to full intensity so switching them on the fly doesn't work the same as halogen.

The proper method if retrofitting HID to an H4 housing involves installing a projector system.  The projector has a lens to focus the light in the correct pattern, as well as having a solenoid operated shutter to flip between low beam (dip beam) and high beam.  That means the HID bulb never turns off.  It also accounts for the fantastically sharp cutoff pattern one sees in a projector system.

A H4 HID should have no lag going from Low to High Beam etc.  Yes the HID does take time to warm up, but in conventional H4 bulb you have two filaments one for low, one for high.  In a HID with one 'arc' they do this by using a servo to move the 'arc' back and forward changing the position to give you the high/low beam effect.  The arc is not switched off so has no warmup time when switching.

If you had two separate bulbs for low and high I agree the lag while warming up would not be a good thing.

I did have a HID bulb in the sidecar for a while, lit the road up well, did not affect the reflector or the glass at all.  but the beam was not as defined and eventually the high/low servo got lazy or gummed up and you couldn't tell the difference between high or low much at all.

Al

About twenty years ago I tried chrome spray paint and it wasn't very good. But a guy I was talking to raved about the new Chrome paint. As I am not into chrome I didn't get what brand it was. With the debate on what to do with deteriorating reflectors. I did a search and came up with VHT chrome paint, it states in the spiel for tail light reflectors and outdoor lighting. I don't know whether it would take the heat of a headlight. I might be worth a try if someone has a headlight with a stuffed reflector and is willing to have a go. https://www.ebay.com.au/itm/VHT-CHROME-PLATE-SILVER-FINISH-SPRAY-PAINT-11-OZ-CAN-VHT-SP5251/121152482493?hash=item1c35402cbd:g:HUQAAMXQxU9R-M6T
Regards Martin.

The quality of the finished product for chrome paint is very dependent on the skill of the person applying it and less on the quality of the materials (but I'm not saying that they don't matter at all; quite the contrary). I had some parts of my motorcycle painted in chrome and some turned out great, others were a complete disaster. The difference was not the parts or the paint, but the degree of detail paid to the job by the painter.

There are no home application kits available that can achieve the results that a professional with professional equipment and excellent knowledge can achieve.

You are probably right Rob however it might be worth a go. Another question while the RT/LT headlights might not have been used on any others vehicles. Was the one piece K75s headlight common on at cars of the time, I have been trying to research it but have so far come up blank.
Regards Martin.

these seem to work quite well ...for a standard halogen type globe at least
nice bright hot spot right on the road in front
high beam is pretty good too

MartinW wrote:You are probably right Rob however it might be worth a go. Another question while the RT/LT headlights might not have been used on any others vehicles. Was the one piece K75s headlight common on at cars of the time, I have been trying to research it but have so far come up blank.
Regards Martin.

I think you will find that those lights are the same as the Valiant Chargers had and very similar to the Z1300 Kawasaki. They were made by Stanley and are almost impossible to get second hand and new ones just don't exist. They haven't been made for at least 20 years.

MartinW wrote:You are probably right Rob however it might be worth a go. Another question while the RT/LT headlights might not have been used on any others vehicles. Was the one piece K75s headlight common on at cars of the time, I have been trying to research it but have so far come up blank.
Regards Martin.

The K75s headlight is the same as the headlight used in an R100GSPD and some R100GS Paralever models (not the first of them).

Al

Thanks fellas beside the Charger there must have been more cars with them. Possibly Cortinas, and others.
Regards Martin.

One of our US or Canadian inmates might be able to answer whether 1980's onwards Jeep Cherokee  rectangular 7' x 5" headlights would be interchangeable with the K75s. 
Regards Martin.

StefanMajonez wrote:

Point-Seven-five wrote:The problem is the plastic connector on the wiring harness.  It is necessary to replace it with a ceramic body connector to prevent the additional heat from melting the plastic.

I haven't thought of the connector, thanks!

I bought a few of these on eBay and did a test in my 84 K100RT. Plastic bulb holder will melt. Very effective with a 160/130W bulb. BUT you have to have the relay, and ceramic bulb holder and you will have to aim the lights slightly lower and slightly to one side. I have used them in the car and it has passed the MOT check with them in. In our case its only the dip/low beam that's assessed.

Another thing making a big difference is the reflector itself. I did manage to get some brand new old stock and now have them to do both the K100 and the K1100. Also remove the glass and clean the back. There seems to be a difference in earlier and later headlight units too but I seem to have acquired non plastic components so should be ok.

MartinW wrote:One of our US or Canadian inmates might be able to answer whether 1980's onwards Jeep Cherokee  rectangular 7' x 5" headlights would be interchangeable with the K75s. 
Regards Martin.

AFAIK this headlight was special made for BMW by Bosch.
As allready mentioned also used on some GS models.....and also F650.
The Bosch part number is 0 303 750 100.

Thanks Inge I have had a look at one at a mates place and it is held in position with the 3 adjustment screws. I had a look at replacement 7" x 5" headlights on Ebay and none have that feature. Although with a bit of playing around I think you could get one to fit. I looked at a few LED ones and thought about getting one, but they would be illegal here.
Regards Martin.