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Old 04-22-2010, 08:05 AM
Nougat Nougat is offline
Motorized Bicycle Elite Member
Join Date: Nov 2009
Location: Montgomery, IL
Posts: 1,332
Default Re: What's with the bottle

I think I was the one who said the blowback would take the path of least resistance. After some looking, apparently what's supposed to happen is while the intake draw is going past the boost bottle, it draws some air out of the boost bottle, making a little negative pressure inside the bottle. That negative pressure is relieved by some of the blowback entering the bottle.

Some more digging shows that a lot of stock dirtbikes and snowmobiles have factory boost bottles, which lends to the credence of the idea.

Still, it's one thing for a Yamaha or Kawasaki engineer to design an engine that includes a boost bottle, and quite another for amateurs to add something that looks like a boost bottle to an badly designed engine that didn't have one in the first place.
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