This mod has been around for a while and I've known about it for years but, for some reason, only recently decided to play with it when I had the HES cover off to add a temp sensor to my K75. So today I did some poking around on various forums and other places and figured it was worthy of being posted in The Lieberry. Here's a brief summary on the topic.
WHY do owners do this?a - To give your bike a little better throttle response and a liitle more "zip"
b - In some cases it's been reported to have made K100s a little less buzzy
c - Possibility of slightly better meilage
HOW to owners do this?By rotating the Hall Effect sensor
clockwise (when facing the engine from the front.) You can accomplish it either by eyeballing it or using a timing light.
One thing I've discovered after installing a few HESs is that just lining up the notch on the right side of the HES carefully will get you just about spot on with respect to factory timing. After installing three or four of them and then verifying the timing with a timing light I came to the conclusion that all you really have to do to set it to the factory timing is to line up the notch in the large timing cover with the notch in the HES. Like so:
The two 3mm Allen head cap screws in the blue circles are what you loosen in order to rotate the HES. You don't need to remove them completely, just loosen them enough so that you can rotate the HES.
The old IBMWR tech write-up is to advance the timing three degrees but others have done it higher to four degrees or so and reported favorable results. Here's a link to an IBMWR write-up on how to do it by measuring and adding a new timing mark:
http://skylands.ibmwr.org/tom/tech/k75_timing.htmlIf you're using a timing light then connect it to the #1 spark plug lead for a K100 or the #3 lead on a K75. If you have a timing light that's adjustable then just set it for three (or four, whatever) degrees and use the factory timing mark.
The other approach is to try it at different positions and see what seems to work best on your bike using whatever octane fuel you usually use. Make sure to ride it enough to let the engine get up to normal operating temperature and run it through the entire RPM range. If it's "pinging/knocking" under acceleration then you've probably advanced it too much and want to dial it back a bit.
Since I plan to fiddle with this in the near future I made myself a crude graphic for eyeballing it by imposing a section of a protractor on a picture of a K75 HES. It's attached below.
And here's a link to a previous motobrick thread on the topic:
PS: I've never heard of anyone trying this on a 4V K but I may experiment with that a little over the summer.
