MKL's 2004 BMW R1150RT
Kisan P115W-H7 Headlight Modulator Test
The Kisan P115W-H7 Modulator and modified RT Bulb Assembly Cover (8/06)
Background: Kisan Technologies is well known to conspicuity-conscious BMW riders as a company which produces excellent modulators, and for the late model Oilhead RT, they offered a modulator Model P115W-H3, which worked by modulating the H3 High Beam bulb. Having just gone through the torturous task of replacing all of the OEM bulbs in the headlight assembly last week, I was not about to do anything that involved getting to that H3, nor was I interested in any wire cutting and splicing, as required to install the P115W-H3. Having used the Kisan P115W-S90 on my Harley Sportster for years, I wanted something similar to that device - a plug-and-play module that was extremely easy to install, required no wiring changes or splicing, and would operate reliably. The answer came in the form of the P115W-H7, a more generic modulator aimed at motorcycles with H7 beams. Granted, it's the high beams that are typically modulated - but why not try to modulate the H7 low beam on the RT? On this bike, the high beam operates independently of the low beam and thus can be turned on or off in conjunction with the modulating low beam. My theory was that by choosing to modulate the low beam, I could install this plug-and-play device with (by far) the most easily accessible bulb in the RT's assembly, the low-beam H7.
Installation: The picture above shows the basic components of the modulator. Essentially, you have the brain, which is mounted external to the plastic bulb assembly cover using supplied velcro. Leading into the bulb assembly, you have the wiring harness. In short, the female side of the Kisan harness lead plugs onto the H7 bulb, and the RT's bulb socket plugs over the male side of the Kisan harness lead. Literally as simple as changing the low beam H7 bulb. Getting the harness through the RT bulb assembly's plastic cover is where you can get creative.
As shown in the picture above, I decided to use a simple rubber grommet. I found one at the local hardware store for 5 cents, drilled the requisite 3/8" hole in the plastic cover, and routed the Kisan harness through. Cheap and quick. For good measure, I added a tiny amount of RTV where the wires go through the grommet, just to make sure it is water tight, and it is. Once everything is hooked up, you simply reinstall the RT's plastic cover over the bulb assembly as usual (everything fits fine) and find a place to mount the photocell daylight sensor.
This tiny sensor, which plugs into the brain, serves in this application to stop low beam modulation whenever darkness is detected (entering a tunnel, night riding, etc.) You can adjust light sensitivity as well, though the default setting is quite good. Some riders have elaborate solutions to the photocell mounting dilemma, but I simply ran the photocell wire along the power wires running up the handlebars, and zip-tied it just out of sight (but where it would get direct sunlight) next to the left side switch cluster. Crude, but effective and most of all... easy.
The Modulator's Tiny Brass Colored Photocell Mounted on Left Handlebar via Zip-Tie (8/06)
Operation & Conclusion: Everything works as expected. We all know how modulators work, so I'll skip the basics, and say that going this route on a late-model RT is definitely a less painful install than the P115W-H3, since the H7 low beam is so much easier to access than the H3 high beam. Also, this is plug and play - no splicing. With a decent low beam bulb, such as my Philips VisionPlus H7, the modulator is quite effective, even though it's "only" the low beam that is pulsing. For extra conspicuity when you need it, turn the high beam on as well. And, as a bonus, ancient fossils in cages creeping along at 50% below the speed limit in front of you often mistake you for a LEO, and pull over obediently so you can pass. Life is sweet! As such, those late model RT owners who want to install a modulator with a minimum of fuss should consider this option most worthwhile.
The Finished Installation of the Modulator (8/06)
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