Air Intake Discovery

tdragger

Living Legend
Joined
Jul 8, 2007
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Fredericksburg, VA
Last year I bought my wife a '97 Yamaha Virago 750 as a beater bike for her to gain some experience on. It's been great, however, this winter has taken it's toll and the front cylinder is not firing. My guess is the ethanol crap that they put in the gas has sat long enough to gum up the carb.

I started the teardown last night by pulling the airbox off the front right side. If you have never seen a Virago intake system you'd be amazed. The airbox on the right side contains the filter, of course. Upon leaving the airbox, the intake connects to the frame where a built-in airway exists to transport the air down the frame until it reaches outlets to feed each carb. Absolutely bizarre.

When the airbox came off, I noticed a rattling sound like it had pebbles in it. I shook it again and sure enough the muffled rattling happened again. Being curious, I went ahead and tore down the airbox and discovered that a mouse had apparently been using the airbox as a storage box. The problem was that the mouse had been storing rat poison pellets as well as sunflower and various other seeds. It is amazing the amount of rat poison that it was able to store before obviously succumbing to the poison.

Now another more mechanically related question. I also removed the intake hose that connected the airbox to the frame and noticed some sort of goop puddled in the hose. It's seems to be petroleum based and almost like parrifin (sp?) or something. See the attached picture. Note, you can see where I stuck my finger into it. What could be causing this?
 

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Funny! (NOT!)
As far as the goop you found, most of the bikes I've worked on have "plumbing" to pull unburnt gases from the crankcase back into the airbox to be burnt again. These unburnt gases consist of oil, moisture, gasoline, and other combustion byproducts. Perhaps with such a convoluted intake system, some of this mixture has dropped out of suspension and settled where you found it.
On my Thunderbird triple, this started happening when I drilled my airbox to allow more air in, thus reducing the vaccuum available to pull the gases back into the intake.
Hope this helps!
 
Thanks, Bobby. That makes sense. So in other words, it's somewhat normal and don't worry about it.

Now to get that **** carb off and cleaned up...
 
On the good news side, just imagine if you weren't a wrench, how much would the bill be for the repair? And you would be paying for them to laugh at you for killing a mouse! LOL

What a bizarre air delivery system ... combination of design and mechanical engineering to save money and still look like an American V-twin? Question is, does it work any better than just slapping a small round filter on each T.B.?
 
LeAnns's "Big Red" had a mouse set up camp in her underseat filter box,
inside the filter.
cleaned it all out, got her a new filter cause the mouse had chewed the one up
making a 'bed".
put some wire mesh over the hole he'd chewed to get in there through the plastic top.
No mice lately.
 
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