Topic: Black Powder?

[DHolbrook]

I usually ride (stock 750 k6) about 5 miles on city roads to work and back day to day.  Last night I rode it at about 75mph on the freeway for about 20 minutes.  When I got home I noticed some black powder like residue on my left pant leg from my knee to my ankle.  This stuff wasn't wet, and about 50% of it brushed off when I rubbed it.  It didn't have any particular smell.  What could this be?  Something from my #1 exhaust flange?  Something from the road?  I haven't made any changes to my bike except a few basic tune up items.

Thanks

[754]

If it is exiting your exhaust, it should leave a trail....

[DHolbrook]

Ok, maybe my #1 exhaust.  Is this a problem?  Can I just install some new exhaust gaskets and it will be fixed?

[andy750]

Ok, maybe my #1 exhaust.  Is this a problem?  Can I just install some new exhaust gaskets and it will be fixed?

Not a problem per se unless there is an air leak (you might here a tapping sound). But to fix, get a new copper gasket and reseal. Or first try to tighten up the 12 mm bolt and see if that helps.

You may also be running rich and riding to work 5 miles may be causing excess carbon build up in that area. Perhaps the 75 mph speed was good for cleaning it out. I also ride 5 miles to work each day on my K4 and have not noticed any excess carbon in that area...I run Denso spark plugs (good fat spark) and running a tad rich but nothing too bad.

good luck
Andy