DT125R ARCHIVE

DTR_NW · DTR Senior Member

what do these bottles do

MDK · DTR Legend

the expansion type bottle.s some have one between carn and head ond others have two 1 each side of carb ???

I my self have never realy understood what these do and how or why ???? anyone explain in understandble terms ?

DTR_NW · DTR Senior Member

i was reading another post on here but people where all jumbled up

there are 2 bottles

one is on the reed block right after the carb

one is before the carb attached to the air box rubber to the carb

apparently one is a restrictor one isnt

can anyone clarify this for us

when i purchased mine it had a bottle cap in the air box one i removed this ran 100% better for me alot quicker more responsive

( but my air fuel needle is jammed ) so could be that the hole does need covering and my fuel air mixture needs altering so any advice is greatly apreciated

NEV · Guru

The one on your reed block is the boost bottle, whereas the other one was a restriction in later model DT's

MDK · DTR Legend

NEV wrote:
The one on your reed block is the boost bottle, whereas the other one was a restriction in later model DT's

so would you advice the restrictor bottle [small one on left bolted to frame between air box and carb] should be removed and the hole sealed ? maybe with a cork or rubber bung ?

DTR_NW · DTR Senior Member

a coke bottle cap fits in the perfectly doesnt move but like i said if i cover it bike runs slower

eG x LoGiKzZ · Guru

i dont see the point of the 'boost bottle' on the inlet manifold, haven't ever seen another bike with one so can't see that it would make any increase in power or throttle response, ive never tried blocking it off tho

DTR_NW · DTR Senior Member

i dont understand the advantage of it either

Energized · DTR Legend

Apparently it's a pointless restriction, the one on the side of the bike. Where as the one inbetween the reed valve and carb is a boost bottle, meant to store mixture for a little *boost*. I've took the restrictor off the side, bottle cap in with some sealent, happy days.

DTR_NW · DTR Senior Member

again so how come my bike runs slower when i put a bottle cap in there ?

Energized · DTR Legend

No idea, maybe it's fooked the amount of air your getting etc.

the only way is YAMAHA DTR · Guru

YAMAHA ENERGY INDUCTION SYSTEM aka Yeis

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DTR_NW · DTR Senior Member

suppose god knows lol need to sort ma carb out

NEV · Guru

MDK wrote:
NEV wrote:
The one on your reed block is the boost bottle, whereas the other one was a restriction in later model DT's
so would you advice the restrictor bottle [small one on left bolted to frame between air box and carb] should be removed and the hole sealed ? maybe with a cork or rubber bung ?

From what I've read aye it seems to work, when removed, but to be fair you'd need to find someone with a later DT , as mines the earlier one, and as ya know we don't have one, maybe that speaks volumes in itself.

DTR_NW · DTR Senior Member

yea once i sorted my power valve and carb out i block the hole off with a bottle cap (perfect fit) now runs like a dreammmmm

-- Edited by NEV on Wednesday 11th of July 2012 01:26:15 PM

AndyYam · Guru

The Boost bottle or YEIS ( Yamaha Energy Induction System) is not a restriction. This is the bottle that fits into the top of the inlet manifold. My RD350 just has a balance pipe joining the two inlets but people ave produced a boost bottle in the right shape and size to kill of flat spots around 4krpm. I copied and pasted the following rather than typing out..

"YAMAHA ENERGY INDUCTION SYSTEM (Y.E.I.S, "Boostbottle")
Y.E.I.S is a very efficient invention. A small bottle ,often called "boostbottle", is installed between the carb and the intake port connected with a branch pipe to get the engine to respond quickly from bottom end without flat spots.
It saves 10-15% in gas consumption and makes the engine wake up at lower rpm.
Like many of Yamahas inventions. When it first came out there were many doubters. Just as they doubted the wisdom of a separate oil pump and the 7th port. Or Torque Induction. But if done properly this does work.
many people have since copied this modifacation.. The most common mistake people make is not placing the boost bottle above the cylinder, not getting the size right and using a common bottle for two cylinders and failing to make sure that the bottle drains back without collecting fuel.

Since Carburators can carburate both in and out, when the charge is out of
phase with the engine it creates a double dipping intake charge (passing the
jets twice). This kills the engines ability to make Torq due to this RICH
condition, thus creating the Torq\HP DIP just before the engine starts to
take in the charge and use it all. This Power dip can be seen in both 2 and
4 stroke engines. The ~BOOST~ Bottle will help cure the problem by providing
a storage tank, of the required volume and distance to resonate at this RPM.
It stores the charge that once reversed back through the carb and returned
as a DOUBLE RICH condition."

NEV · Guru

Aye Andy, its been established the Y.E.I.S. or boost bottle isn't a restriction, it's the other bottle on the air box that was put on later models, thats the queery here, I woulda thought that with the earlier DT's not having one, that maybe this was some kind of restriction.

AndyYam · Guru

NEV wrote:
Aye Andy, its been established the Y.E.I.S. or boost bottle isn't a restriction, it's the other bottle on the air box that was put on later models, thats the queery here, I woulda thought that with the earlier DT's not having one, that maybe this was some kind of restriction.

Like wise. With the engine sucking air in through the airbox, the bottle on the side is going to grab a load of that air and restrict the amount that actually goes through.

When it is removed and not blocked it'll be sucking loads of dirty air in from outside as it's bypassing the air filter which yeah may make your bike run faster but for how long? Your mixture will be too lean and you run the risk of running way too hot etc etc.

Just like people who drill holes in the airbox on cars.

Block it off and it's going to perform just as the earlier one. Even better, replace with an earlier hose.

Thats my theory anyway.

NEV · Guru

DTR_NW wrote:
yea once i sorted my power valve and carb out i block the hole off with a bottle cap (perfect fit) now runs like a dreammmmm

Just as a matter of caution, ride a dozen miles or so and whip the plug out and check its colour, just incase it was richened up on the carb to compensate the fact that there was no bottle there, drawing air in and possibly making it run a tad leaner than it should have been doing.

DTR_NW · DTR Senior Member

no mate there was a bottle when i got it but my power valve was setup weird so i took the bottle off got a tad more speed but then when sorting the power valve out just blocked the hole up so is all running fine will clean the plug then take bike to work tomorrow check again

the only way is YAMAHA DTR · Guru

why would they restrict it there, there are so many different ways to restrict a bike, i have blocked it off and never noticed a difference,

now i remember reading somewhere, the wr200 had them fitted(i know this for sure,) that its to store a volume of air for a low down pull away punch,

why would they restrict a mx bike?

NEV · Guru

NEV wrote:
DTR_NW wrote:
yea once i sorted my power valve and carb out i block the hole off with a bottle cap (perfect fit) now runs like a dreammmmm

How about trying it with that bottle back on, now that you've sorted out the P/V? and can compare it to not having the bottle on?

AndyYam · Guru

the only way is YAMAHA DTR wrote:
why would they restrict it there, there are so many different ways to restrict a bike, i have blocked it off and never noticed a difference,
now i remember reading somewhere, the wr200 had them fitted(i know this for sure,) that its to store a volume of air for a low down pull away punch,
why would they restrict a mx bike?

Thats my DT200WR. It doesnt have a bottle like the DTR.

AndyYam · Guru

Say that, the manual I have for a wr200rd shows a bottle like that as can be seen below. Interesting...

AndyYam · Guru

Come to think of it, maybe mine does have a that bottle, ill check soon.

the only way is YAMAHA DTR · Guru

ye its in a different place than the 125

DTRDavey · DTR Newbie

I understand what the bottle on the inlet manifold is for, I can make sense of that, but the one on the carb intake makes no sense whatsoever to me.

Have a look at this link, apparently the 4DJB and 3MRL models dont use that bottle, are those models de-restricted?

http://www.yamahamotorcyclespares.co.uk/spares/epc2.asp?modelID=9134&PageiD=6&m=YAMAHA+DT125R+++2002+INTAKE&uID=0

Also have a look at this exhaust (from the same model), there is what seems to be a bolted joint near where the restrictor plate should be...

http://www.yamahamotorcyclespares.co.uk/spares/epc2.asp?modelID=9134&PageiD=9&m=YAMAHA+DT125R+++2002+EXHAUST+2&uID=0

I think its criminal how they have restricted these bikes!

PS. Regarding the WR250 with similar bottle, are 250's not restricted to below 33 bhp nowadays?

AndyYam · Guru

I don't think that bottle can be a restriction. I don't see why they would restrict a competition bike like the wr200 which has a similar bottle on.

Davey, thats interesting. I've never seen an exhaust like that. Their numbers are wrong based on their key as its labelled as a stud lol.

NorDt · Guru

its a vacuum bottle, Its supposed to make ur bike faster, More throttle response or something, Im not quiet shure how it works. But fuel/air is sucked up inside it when you release the throttle. And goes back into ignition when you give throttle. i think xD

AndyYam · Guru

Your talking about the YEIS again.