a vacuum can?

[carnut14]

So yesterday I purchased my first bike. Its sort of a project put it was/is? a runner. The fellow I purchased it from had multiple bikes for sale and all (natch except the one I chose) had a small juice sized can that was attached to the carb manifold via a small vinyl tube. The can typically had a screw on lid that sealed with an o-ring. Any one know what this thing is and/or why it would be required?

New to the forums, apologies if this is posed in the wrong place.
Carnut14

 

[FOG]

Sounds like a boost bottle and not required. The idea is to set up some kinda resonance in the intake tract to widen the powerband on a 2 stroke motor. The volume of the "bottle" is normally somewhere near the displacement of the motor itself.

There are people whose opinions I respect that claim they are useful on smaller 2 strokes ... and I may try one myself someday.

I hope that's the correct answer to your question. Best guess anyway.

 

[Greg58]

Snake oil! I haven't tried one but the builders here that do this every day say they do nothing.

 

[Greg58]

I’m with Allen, the only way to prove the boost bottle is to try it myself. I have one bike that I’ve been using to test several pipes on that I will try it on, I’m not buying a kit I’ll make it myself.