Air chamber 2 on DT125r

[Kev]

Hoping someone can satisfy my curiosity, as I cant get an answer off the Dt forum, as to the purpose of the item known as air chamber 2 which is mounted between the air filter and the carb, unlike the yeis chamber which is forward of the carb. Not present on all models but just the last prior to retirement. Hoping to hear about tbe science not just that " its to restrict it" thanks in anticipation.

[jamietzr250r]

An air chamber is normally a  pulsation-damping device.
It reduces the pulsation of a reciprocating pump and contributes to stable liquid flow by utilizing the compressibility of the air in the chamber.
It could be doing the same thing to the air flow through a carburettor (technically it is a pump)....

[Andy Bush]

Hi Kev
I did a fair bit a work on my DTR and after some mods I found that mine ran better without that chamber. Dialed the jetting in and found an improvement at very low, throttle openings without it

[Kev]

Cheers Andy, I can't find anything on the web about this device, dtpedia.dt explain the science behind the snorkel and the yeis bottle but not this restricting bottle. As the older air filter to carb boots become brittle and leaky these boots with extra hole may have to fill in to keep the bikes going.

[AndyYam]

I always thought these were part of the restrictions on the later models. Most people seemed to use a coke bottle lid to plug the whole it left. Or but a 3MB carb to airbox boot that doesn't have it.

My 54 plate RE always had it fitted but this was also restricted by an exhaust full of Cat, switch in the speedo and ofcourse CDI.

[ybk]

The SPR also has a similar add on chamber to the right side airbox's intake area. Always thought it was just to increase the airbox volume but a damping device sounds more plausible...

(stealing Searick's picture  ):