Re: bad gas mileage

["Steve Makohin" <wateredg@xxxxxxxxxxxx>]

Hey guys,

From: "Clive Liddell" <cliddell@xxxxxxxxxx>

> Bill, you wrote:
> "BTW: What plugs did you use. The original Bosch are a poor choice and
> the recommendations of the list are mostly anecdotal; BMW switched to
> NGK and that is what I use. In fact, I have been using them since NGK
> made them available since they were specifically designed for the R11
> and R1150."
> =======================
> I only know of NGK plugs being specified for the R1100S bikes.   The 
> switch
> to NGK by BMW that you mention could be a BMWNA thing?
>
> I am still merrily (and with no trouble) using Bosch.  They stay in till 
> the
> electrodes are worn to > 1mm, usually 35000km.

According to John Parker, skilled engine tuner and lead technician at Budds 
BMW, he says that preferences for spark plug brand is like a religion: 
People swear by it because they allege it makes their life better, but they 
don't know how it works. Autolite plugs are a famous case in point for their 
alleged ability to reduce or eliminate surging in Oilheads.

My R1100S surged, and John Parker fixed it. And he knows why his fix worked.

According to Parker, a single spark plug in the center of a large cylinder 
is theoretically efficient. But in practice, slight physical differences can 
make large changes in the rider's experience. He experimented with a number 
of solutions to address the surging, and ended up settling on using the NGK 
BKR6EK sparkplugs with a more projected tip and a slightly different heat 
range as compared to the factory part. Parker says that having the ignition 
source just a little deeper in the cylinder may make a substantial 
difference. It did in my case.

Coincidentally, the famous Autolites that are said to cure surging also have 
a projected tip. The first person who discovered this probably had a Ford 
vehicle and a spare set of plugs, and just decided to try them on a surging 
Oilhead.

Note: Parker warned me that before I "shoot off my mouth on the Internet" 
(he used slightly nicer words), make sure I mention that his experience 
indicates that the plugs he installed for me aren't a magic bullet. They may 
not do the trick on another Oilhead, nor even another R1100S. I guess that's 
where having a skilled engine tuner helps.

- -Steve Makohin
 '01 R1100S/ABS
 Oakville, Ontario, Canada 

------------------------------