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2009-05-12 Dirty Throttle Bodies

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...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.

Posted 13 May 2009 - 11:42 AM

So you are saying they looked like these?: Clicky HERE and scroll down for TB photo

How did yours compare to my photo?

My guru mechanic, without seeing the photo but based on my description told me it's most likely normal for my high mileage and caused by 'normal 'backwards pulses' of air through the intake.

I also wondered about the crankcase breather hose? Bringing oily vapored air into the airbox from the crankcase?

Edit: Here's just the photos from the link above. My 'gunk' was gooey too.

 

Posted 13 May 2009 - 12:32 PM

QUOTE (SkooterG @ May 13 2009, 11:42 AM) <{POST_SNAPBACK}>

So you are saying they looked like these?: Clicky HERE and scroll down for TB photo

How did yours compare to my photo?

My guru mechanic, without seeing the photo but based on my description told me it's most likely normal for my high mileage and caused by 'normal 'backwards pulses' of air through the intake.

I also wondered about the crankcase breather hose? Bringing oily vapored air into the airbox from the crankcase?

Edit: Here's just the photos from the link above. My 'gunk' was gooey too.

GREAT post, thanks SkooterG! Yeah, that's what mine look like, only mine had no 'brass' showing at all on the bottom halves - they are entirely black and gooey. From your pix, it looks like someone has already 'cleaned' the top half and portions of the lower half as well?

The crankcase breather tube injects dirty air downstream of the air filter, and I consider it suspect too. Take a careful look at the inside of the cc breather tube in your pix - do I see crap in there?

When I get CrZy8 back I'll do a compression check, and maybe get all inspired and put a k&n filter on the cc breather tube, block of the hole in the air box caused by removing the hose, and install a Uni air filter. Of course, it all might just have to wait until after CFR.

Posted 13 May 2009 - 03:22 PM

Ok, here are the pix, taken with a BlackBerry..

The one smudge in the middle pix is where I used my finger to wipe through the goo...

What do ya'll think? Normal or a problem?

Walked away :) Posted ImageIs it really crashing if you don't fall down?--

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