Idle Air Bleed Screws Carbon Build-up

[HaulinAshe]

Or AIS spooge.....

+1

I totally disagree with the mechanic's diagnosis of carbon buildup. IMO what he saw was what many of us have seen many times before...

... Substantial buildup on/in the throttle bodies from regurgitating PAIR system, crankcase relief system, fuel vapor return (CA models), and all the other hosts of systems designed to return the less-than-desireable elements back to the engine for consumption.

Clean the throttle bodies thoroughly, cap the PAIR system and move on.

 

[wa2fst]

Maybe we should also consider the crankcase breather...it could also be a source of "oil fumes" that get sucked into the TBs and onward into the combustion chanbers. I know that at 40,000 kms my throttle bodies were very badly grunged and my pair system was very clean when I inspected it at the same service.

Just my 2 cents worth. :lol:

 

[RadioHowie]

Maybe we should also consider the crankcase breather...it could also be a source of "oil fumes" that get sucked into the TBs and onward into the combustion chanbers. I know that at 40,000 kms my throttle bodies were very badly grunged and my pair system was very clean when I inspected it at the same service.

Just my 2 cents worth. :lol:

I see your 2 cents and raise you a spotlessly clean, grunge-free airbox at 46,000 MILES (not those ghey kilometer things)

with throttle bodies that look like this

The sludge was NOT from the PCV/Crankcase Breather. Trust me.

 

[carlson_mn]

This is actually kind of a good thread.

 

[RadioHowie]

This is actually kind of a good thread.

Sorta like "Andy **** is actually kind of a good comedian"???? :lol:

 

[SkooterG]

with throttle bodies that look like this

The sludge was NOT from the PCV/Crankcase Breather. Trust me.

So WHAT was it from? I know we have had this discussion before with no definite consensus as to root cause. Mine looked like those with 160k, Carver's looked like those. I have had a few others PM me saying theirs looked like that. WTF causes it? While my TB butterfly valves looked terrible like that, the intake passages of the head were spotless. WTF? Static cling?

I ran a K&N filter for about 30-40k miles at one point. Perhaps filter oil? I know of well-respected FJR owner that thinks running a K&N and the filter oil had a detrimental effect on his throttlebodies. Any other of you run the K&N?

Unlike you RH, I also can get some of that dark nasty spooge in my airbox. Especially at the intake 'horns' or tubes.

Odd. Just plain odd.

 

[RadioHowie]

So WHAT was it from? I know we have had this discussion before with no definite consensus as to root cause. Mine looked like those with 160k, Carver's looked like those. I have had a few others PM me saying theirs looked like that. WTF causes it? While my TB butterfly valves looked terrible like that, the intake passages of the head were spotless. WTF? Static cling?

I am convinced it was deposits from the air injection system. The "tee" from the crankcase breather at the top/center of the airbox picture was clean and dry, but the AIS return port, which you can't see in the pic, was sticky/dirty. And the intake passages of MY bike looked as bad as the TB plates.

Unlike you RH, I also can get some of that dark nasty spooge in my airbox. Especially at the intake 'horns' or tubes.
Odd. Just plain odd.

Funny thing is, the interior of the box, including the "horns" was clean, but the upstream side of the throttle plates looked like ***. Gummy, sticky mess.

I probably should open the box up again and take a look at the throttle bodies, 20k miles after yanking the AIS system and cleaning the TBs, to see what's up....but I'm nowhere near, in my maintenance cycle, to needing to yank the airbox anytime soon.

 

[dcarver]

I ran a K&N filter for about 30-40k miles at one point. Perhaps filter oil? I know of well-respected FJR owner that thinks running a K&N and the filter oil had a detrimental effect on his throttlebodies. Any other of you run the K&N?

Running one now, but not before or during my dirty throttle bodies. I too have removed PAIR but not since looked.