Boost bottle facts?

[Greasemeup]

Was looking up YEIS which was on a Japaneese RD product brocure, came up, surprisingly, with this-

https://au.answers.yahoo.com/question/i ... 317AAdCQ7B

Ya learn something new eh!

[hybrid]

Yeah I'm not convinced.
I have one on my LC, but I don't think it's any better than the balance pipe was.
Why would the resonating pulse go into the boost bottle instead of just going straight past it and out the filters, or back to the airbox etc.

Maybe someone needs to make a clear one and film it in slow motion with the engine running to see if it actually does anything.

[JonW]

Ive had YEIS on a DT200R and I think it was fine on that motor, but.... if you read that response you can see why just making up any old bottle and bolting it on an LC/RZ and hoping it will work, as most of the aftermarket manufacturers seem to have done, will not give you the results Yamaha got when they did it with science. It needs to be the right size for the engine, and it needs to not be shared across the cylinders

From that link:
Best Answer: 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.

What I see is an issue with these is that we dont know how big they need to be to work at the right revs (ie those you want to improve - usually the 5-6k stutter, or torque low down), and even then will the over charge be used up on the next intake or just be left in the bottle, if it is, then within a few revs youre no better off.

The other thing I always thought would help is to have the bottle on the inside the reed cage, that would add some much needed CCV for a 350 and seem more likely to be the first port of call for the provision of more fuel/air for the next stroke, but I am no expert.... (cue someone to say 'obviously...' LOL)

One thing Ive always wondered is why people didnt take 2 DT yeis bottles and plumb them to an LC/RZ, always seemed an obvious easy test to see what happened...

[mboddy]

Sorry Jon but I don't think more crankcase volume is the answer.

What Yamaha did on the R1-Z (1990-1993) was fit a T between the inlet manifolds which connected via one short tube to the boost bottle.

[JonW]

I was only thinking adding CCV would be useful for the 350+ motors as Ive read that tuners find the engine lacking in that dept since it was designed with 250 in mind. Im not suggesting that a boost bottle is for that job, just wondering if it could help if plumbed right. From what Ive seen over the years most modern tuners have issues with some of the fundamentals of the RD/RZ motors from a modern standpoint with things like the exhaust being too big and ports not really being where they would do it today if starting from scratch. The price of progress etc. Of course that means that some of the banshee aftermarket units have benefited from that research.

The R1-Z setup goes against what is written in that text GMU found... hmm, more 'proof' perhaps that that this is a subject that few seem to understand it seems. I am defo one of them LOL!

[hybrid]

My understanding is that most tuners are trying to reduce CCV to get more of the gasses into the cylinder instead of staying in the crankcase.
Transfer volume is one of the biggest issues with the older engines, not so much CCV.

[twinrock]

An interesting note..I built an rdlc but the motor I had was missing the aluminium balance pipe..that motor went very hard..best lc I had..was at a mates place and he had a spare pipe sitting on the bench..he said I could have it..so I removed the plugs and installed it..I also was keen for him to have a go as I was so impressed with performane we swaped lcs and when asked what did he think..he wasnt all that impressed..I rode home and was thinkin..man whats wrong with my bike..performancec way down..I pulled over pulled out the balance pipe and put back in the plugs...BANG..!!!back to the fire breathing lc it was before..man never got to ride it but hybrid you bought that engine from me..I remember how impressed u were with it also..now there were other factors with the motor, pipes porting..not sure what carbs were on it.kr1 I think...and I guess jetting was done with out pipe..but it was a dramatic difference with out it..

[BRG1200]

Interesting.
I think the point about science, or loads and loads of testing, is the point. Not many amateur mechanics will have the time, expertise, resources to do it the way a factory or race team would. Nearest I've heard directly is Gibson/Allspeed in Kent, who have had a dyno for the last ten or so years. They did experiment, and if I recall correctly seemed (this was years ago) to think a certain boost bottle arrangement was beneficial. That said, don't know how scientific that testing was, and they wouldn't have had the monitoring and measuring tech of a factory, or the man hours.

Didn't Kawasaki have two separate bottles on the KR1 or KR1S? I feel I've heard that but don't know Kawasakis.

[BRG1200]

Jon, can you put up a pic of the DT boost bottle unit you mention?

I was thinking of putting a balance pipe on my (basket case) RD400, not that its anywhere near running, mostly because I want to change the old rubbers anyway. Not sure its worth doing now!

If a boost bottle arrangement were made in a pair, in a vertical cylinder form like a pair of carb bodies, then a top could be made which could screw up or down to vary the volume. Just a thought.

[JonW]

First hit in google images, I cant sustatiate if its the same as the one I had, I dont have the 200R anymore... sadly... it was a superb bike.

http://mlb-s2-p.mlstatic.com/camara-yei ... 2014-F.jpg

the problem is knowing what is the right size and shape perhaps? ...you could also run a bladder in it/them and put an amount of air in to change the volume perhaps? A lot of work for nowt perhaps.

Im interested to hear Justin's story, I would think that might have been more about the other factors and the engine not needing the balancing for some reason, I doubt very much that all engines benefit from removal...

[James P]

Didn't Kawasaki have two separate bottles on the KR1 or KR1S? I feel I've heard that but don't know Kawasakis.

There is no intake interconnection at all on the KR-1/1S, although the KR250A (tandem twin, rotary & reed intake) did have a balance pipe similar to RD/RZ etc.

If a boost bottle arrangement were made in a pair, in a vertical cylinder form like a pair of carb bodies, then a top could be made which could screw up or down to vary the volume. Just a thought.

One of the Italian aftermarket tuning firms (probably Malossi or Polini) did make an adjustable boost bottle in the late '80s and/or early '90s, but I only ever saw pictures of it - it looked like some sort of bellows arrangement. I'm not sure whether it was self-adjusting or whether it could be adjusted manually. I daresay that something along the lines of an old gasholder (but much much smaller ) would do the job.

It has been said that the volume of the boost bottle should be somewhere around the same as that of the cylinder, but it may be more complicated than that (i.e. the required volume may depend on the effect you are trying to create) .

Regards,
James

[twinrock]

Well I took the boost bottle off the dt200r today...and it did make a difference..way too rich..would not idle and would not rev cleanly through..which means..2 things ..1. on my lc i had it tuned well with no ballance pipe..when installed became too lean giving a flat feeling and loss of power..2 it would seem that u would indeed need to rejet if u installed one.. now weather the bike will run better with out it or not would require more messin about with jetting..could I be bothered..for the sake of this forum just maybe..now I agree that yamaha have far better testing resources and time and money we can only dream of..however..u also have to take into consideration their motivation for the directions they take with an engine eg a dt200 is designed to be a quiet, low polution and fuel friendly polite smooth reliable trail bike ..as they do to a lesser extent with other factory yam 2 strokes but thats not what we the public always want so against yams better judgement we take to modifying..pipes carbs porting blah blah and as a whole prob end up with a better performi g result..apart from fuel noise lol..I have also read thet boost bottles improve fuel economy,,even tho it takes bigger jets, more fuel to make it run? One of the last tzrs 2mas had a boost bottle..it was smaller to the dt and slits and feeds 2 cylinders..

[BRG1200]

good point, they make for slightly different purposes to us.