[beatr911]

redyaris, I see you had planned a warm air mod. Suggest you weld in an O2 bung and plug in a universal O2 sensor to an AFR gauge. You are probably wanting to be close to a stochiometric mixture anyway so a wideband sensor/gauge isn't necessary. The resolution of the inexpensive narrow band sensor/gauge will help you manage the temperature of the air to optimize the mixture. I have one on my Zongshen 200 and it easily detects the mixture difference of the three different exhausts I've tried. You may also see benefit from changing the stock jetting or settings as is.

By cutting the stock windscreen down on the Concours about 4 inches, I recorded a consistent increase of about 2mpg. Seems that in my case the large size of the barn door was good for winter protection but increased drag. Did you see an increase of FE with the larger screen?

To maximize the engine to run at lower speeds due to the taller gearing, investigate advancing the cam timing. This will take some studying of your stock cam lift and timing and comparing it to other slow speed engines, say a Harley or other cruiser. Modification may be as simple as redrilling holes in the cam gear(s) in precise locations by a machinist. The Concours picked up a healthy low and mid range boost by advancing only the exhaust cam by 7 degrees. Mileage was unaffected, but it's overpowered to begin with and turns 4000rpm at 70mph so no advantage was expected.

Recent activity on the Concours forum describes a modification to the airbox inlet where the inlet is restricted to almost half of its original design. I don't claim to understand the resonance benefits but those who try it rave. Search for "2 minute mod" on concours.org. Combined with jetting changes, you may also benefit. Also boosts low and mid range.

This thread is an interesting one on an overlooked bike. Looking forward to more and seeing you compete in Lacey and with Vetter.