2009-05-12 Dirty Throttle Bodies

...really dirty... 

Posted 12 May 2009 - 02:32 PM

~65k 2006, in for wiring harness replacement. Service manager says 'you got to come see this'. "RuhRoh Rollie", it starts, I think.

The airfilter box has been removed, so can directly eyeball the butterfly valves of each intake.

And they are nasty. Each of the 4 are covered with a gooey layer of splooge that looks like oil and fine dirt/dust. Took a finger and 'wiped' it clean. Thickness of the goo was about like 3 or 4 sheets of 20 bond paper, maybe .003" or so? Opend the butterflies and looked down the intakes, and they too are covered, but much less than the backside of the butterflies.

I don't get it, and the SM/Tech say they haven't seen this on other FJR's they worked on.

For the record:

1. I've run only OEM air filters, changed out about every 6,000 miles or so
2. I do live at the end of a dusty dirt road, 6 miles daily, but normally I'm not behind someone e.g. eating their dust
3. I do NOT take an air compressor set at 120 psi to blow the dirt out - tap filter on concrete to remove dust
4. There are no visible signs of leakage past the filter - the air box is tight, the clamps looked good, and all 4 intakes look similary dirty.
5. CrZy8 still seems to run good, gas mileage hasn't dropped, does not burn any oil between changes (3k normal change, 5k max)

Questions -

1. I seem to recall someone mentioned that the clean air system could possible breathe 'dirty' air into the airbox under decel or something? I tried searching but didn't find the thread.
2. I wonder how good the stock air paper filter is.. Maybe a Uni is in order?
3. Could the crankcase breather be the culprit?
4. Has anyone else seen similar intake grunge when you've lifted the airbox?

Hope to have pix later, SM is calling Yamaha.