KDXRIDER.NET

I was checking out an old IT 490 the other day and noticed that Yamaha put on a neat system called YEIS (Yamaha energy induction system). I found that several bikes in the early 1980's from Yammi had them, I would imagine to help boost bottom end power as those bikes didn't have powervalves. Is this a way of "tuning" the intake, like the car manufacturers say "tuned port" or tuned runners? Is it like adding a longer intake manifold without the lenght for more torque?

Now, for entertainment, what would a boost system such as this do for our KDX's? (besides add 1lb of weight.... ) I would guess that the volume of the chamber would have to be experimented with as well as poking a hole in your intake manifold.

I know that the Banshee has the YPVS system and uses the boost bottles in their intake track. I also have seen other boost bottles for the Banshee that claim more bottom, and better equalization between carbs, etc. CC where are you???

Now that I think about it, why in the world would a 490 need more bottom end anyway?? Anyone want to sacrifice a rubber intake manifold for the sake of experimentation? BTW, CC , pm me your address so I can send back your #6 slide.

Boost bottles are like snake oil and witch craft, smoke and mirrors....., I do have a famous bridge to sell cheep

Banshees do not come stock with boost bottles (they are a $30.0 do nothing if you buy one), but they do have a cross over tube, not the same idea.

IMO they do not do any thing and as you know, more people took them off there YZ's to get back a chrisp throttle response.

It likely depends somewhat on the original design deficiencies in the intake manifold, dead air space and carburetor selection relative to the engine's porting and exhaust pipe design - whether or not boost bottles will help an engine compensate for a design shortcoming. i.e. 700 Polaris snow machine engines with Kehin carburetors

I also agree with RBD that a cross-over tube is not the same as a boost bottle but it seems like most boost bottles that I have seen (both that I have used (2)) had this feature which may have been the primary advantage to the 'boost bottle' addition.

I think they would be a waste of money and time on a KDX.

They were used with success on the IT200 so I don't see why they wouldn't on the KDX200.
I'm just now studying the subject and am going to experiment with boost bottles on my 100cc street bike (with reeds and expansion chamber).
For all my info on it and to download my boost bottle resonant RPM calculator go to http://www.dragonfly75.com/moto/YEIS.html

A boost bottle is designed to improve the low end of the Rev range giving an increase in torque & throttle response on engines pre power valve ....as the kdx has KIPS & a resonator chamber I doubt a bottle would work .