Dirty Throttle Bodies

Fred W · May 13, 2009

I still say that whatever it is, it came from the outside, not backward through the manifold. It is very curious that you could collect that much crapola on the throttle plates. Makes you wonder how much got through into the engine? But it still may be "normal"

PA1195 · May 13, 2009

dcarver said:
What do ya'll think? Normal or a problem?

Dirt = better filter, Carbon = normal backflow. Maybe we could gen up a pool, winner gets a treat. Damned if I know where it's coming from. I gave it my best guess above for the fun of it.

What exhaust system do you have, and is your exhaust air induction system still connected?

How do the intake valves look? Same goobers?

Is the airbox and connecting tubes full of a similar mixture? It should be if the source is intake dirt imbedded in oil fumes.

Gary in Fairbanks

wa2fst · May 13, 2009

I had to clean mine during a recent tune up this past winter...they were very dirty too. Based on information from this forum, I checked the airbox, found it dirty (streaked inside as in other posts), and decided to remove the airbox and check further...WOW was I glad that I did. I found the dirt to be a very hard, "baked on" type of goo. I took my time cleaning it with a toothbrush, WD40, and a little brake cleaner as a final wipe clean at the end. With only 41K Kms on it...I was surprised how dirty they were.

https://i656.photobucket.com/albums/uu286/w...0554845x634.jpg

Can't thank the forum members enough for all the info and help on here! I carefully read the threads for several weeks before I started my tuneup...and almost everything posted here about the PAIRS, airbox dirt, air filter issues, etc...was true for me. I took my time and attended to all the things that I discovered and it now runs much better.

Sorry about the photo post...my first effort!

wfooshee · May 13, 2009

Mine were not as bad as either Skooter's or dcarver's pictures, so maybe the original owner had done some cleaning previously. Except for the graininess in Skooter's, it looks like normal oily sludge buildup from crankcase ventilation. The crankcase breather brings hot oil fumes which condense in the intake surfaces on closed or light throttle. higher loads they go through and burn in the cylinder.

Like I said before, I've NEVER seen a throttle plate on ANYTHING with miles that didn't have some of that on it.

Gary · May 13, 2009

I seem to remember years ago, people would replace the crankcase breather tube with a threaded filter, so the intake wasn't inhaling crankcase blow-by.