research

The BMW K75’s headlight is an H4 bulb, like lots of other motorcycles (and most older BMW’s). For example, the Visipath site lists the following BMW models with an H4 bulb:

RT850R, RT850RT, R100, R1100, R1100R, R1100RT, R1100RS, R1100GS, R1150R, R1150GS, R1150RS, R1150RT(2001 & older), R1200C, R1200CL, K75, K100LT, K100RS, K1100LT, K1200RS, F650, F650GS, F650CS, R90/6

I found the following choices for my K75:

1. Kisan P115W-S

The Kisan is highly regarded and at the higher end of the price range, at around $100 street price. There’s a write-up on the installation of this modulator on a K75 here. This appears to be the “safe” choice.

The P115W-S is the “short” version for bikes without a lot of room behind the headlight. My bike has a Pichler fairing with several inches between the fork and the headlight, so I could probably get by with the standard P115W model. Although, as far as I can tell, they’re the same price, in which case I might as well get the shorter model and have more flexibility on how I route the wires.

2. Kriss h44001s

This appears very similar to the Kisan and is about the same price. Like the Kisan, the h44001s is the “short” model. With the Pichler fairing I have, either the h44001s or the h44001 (standard size) should work for my bike. Again, I don’t see a price difference between the two sizes.

3. VisiPath, by comagination

This one is different from the above two, in that it’s significantly less expensive, and appears to have a lot more wire associated with it. So far, all of these choices are “plug-in” modulators, no splicing needed. It looks like the Kisan and Kriss put their electronics inside the H4 bulb connector, so you just sandwich their module in between your headlight and the wire that supplies power to the headlight. The VisiPath’s electronics are in a separate module, with two bundles of wires – one to connect to the headlight, and one to connect to the wire that supplies power to the headlight. It’s quite a bit cheaper, at $59.95 for the 75-watt sS75H4 and $69.95 for the 115-watt sS115H4. My bike has the stock headlight, so the sS75H4 will be sufficient. (I’ve also seen that on Ebay someone has been selling irregularly molded sS75H4’s for about $50, although there aren’t any at the moment.)

This is probably the model I’m going to buy. There is a lot of unused space in the Pichler fairing so I’m not concerned about the extra wire.

4) Splice-in models

I’m ignoring several models of headlight modulator that require splicing, because there are several “plug-in” models available for my bike, and I don’t see any splice-in models that are any cheaper than the VisiPath. Well, except for one, a $25.99 unit from (who else?) JC Whitney. I’m not sure that modulator is even legal, since it has no light sensor to prevent it from operating at night. It looks like it’s about a $5 part marked up to $25.99. No thanks.