boost bottles: yay or nay?

Discussion in 'Performance Mods' started by nickbk, Apr 16, 2008.

  1. nickbk

    nickbk New Member

    hey all,

    since i've started browsing through MBc, ive noticed in the odd photo that some of you out there have mounted "boost bottles". intrigued, i googled said bottle. what i found was a range of articles, stating that its "the best/cheapest mod you can get for your engine" to websites saying they don't give your engine any noticable improvements whatsoever.

    So i put it to you guys. do they work? i'm interested in getting one if they do. i only have a 48cc engine, and the only thing i've to it is install a hotter spark plug.

    any comments would be greatly appreciated, as it would save me time and money if they ARE bogus.

  2. sparky

    sparky Active Member

  3. I can run my bike at 2 mph then roar away at a twist of the throttle thanks to my boost bottle.No bogging whatsoever. Just smooth delivery. Remember to O ring your carb when you do this. Now go look at that thread.
    Last edited by a moderator: Apr 16, 2008
  4. nickbk

    nickbk New Member

    ok, so ive received and installed my boost bottle. the result? it has successfully robbed my engine of half its torque/topspeed. its acting as a governor on the engine! not to mention that as soon as i pull on the clutch, it either stalls, or idles incredibly high. THEN stalls. before you state the obvious, yes i have tinkered with the idle screw. but there doesnt seem to be anything to choose from except idling-like-crazy or just stalling.

    So i assume i have to tune the carby somehow? how do i go about this?
  5. Demosthenese

    Demosthenese Guest

    it sounds like an air leak. Are you sure that all your gaskets and seal are good? When i installed my boost bottle i had to use silicone gasket maker to seal up the hole in the intake manifold that i drilled for the boost bottle. If you have it on idle and then full choke, it should die, if it doesn't there could be an air leak.
    I found when i installed mine that low end torque was less, but acceleration was faster, so you get through that low end really quickly. My engine also gained a ton of RPM in the higher range.
    The O-ring carb thing that large mentioned seems to be important, you should try that too.
  6. nickbk

    nickbk New Member

    whats "O ring my carb" mean? and i bought a pre-drilled manifold with the intake already installed, so im assuming that its airtight. perhaps i'll run a bead of sealant around it just to make sure.
  7. Alaskavan

    Alaskavan Guest

    You can check for an air leak a couple of ways: The engine should die when the choke is applied after the engine is warm. Spraying a little starting fluid around the intake manifold (not the air filter) should have no effect on how the engine runs (if there's an air leak, the engine wil rev). Spraying brake cleaner around the intake manifold should have no effect on how the engine runs (if there's an air leak, the engine will die down).
  8. nickbk

    nickbk New Member

    yeah that makes sense. i tried the choke trick, it didnt kill the engine. the engine just kept on idling at top speed. but if it IS an airleak, why does the engine die on its own after 15 secs? i'll go seal the intake manifiold now, i'll post my results in an hour or so.
  9. Alaskavan

    Alaskavan Guest

    It's probably getting too much air, and not enough fuel. The air going in from the air cleaner sort of sucks the fuel into the engine. If there's air getting in after the carb, the suction could be inadequate.
  10. Well I went and ordered my boost bottle kit from Boost Bottle Industries, and when it finally came 6 days later ($14.95 shipping), It was shipped with the wrong manifold that was listed in the "auction". I contacted the seller and retuened the wrong manifold,and not wanting to wait 2 more weeks, I went to the Depot for fittings and tap. Got it installed and it is VERY hard to start, runs smooth at low rpm, but very poorly at mid and high. I have moved needle, checked for leaks, all is good because it runs fine without it. I have run boost bottles on most of my 2 stokes from 125cc up to 750cc and have notice considerable improvement. My next step is to remove it and measure the volume with marked containers that I use to measure proper amounts of fork oil. Since I got the wrong manifold (which is VERY obvious) maybe I also got the wrong bottle. I will keep ya all posted....
  11. Egor

    Egor Guest

    According to what I read, the boost bottle was designed to be installed on a reed valve engine only. It was short lived on real motorcycles and never was listed as making an engine idle or any mid range improvements. It had a very narrow band of hp improvement if at all. It needs to be installed as close to the intake as possible within an inch, also was intended for a twin cylinder engine. Have fun, Dave
  12. That has been my experience on Yamaha and Kawasaki two strokes. The bottles we used to use were White Brothers, they had special manifolds where the nipples on the boost bottle actually connected to rubber manifolds between the carb and reed cage.
  13. nickbk

    nickbk New Member

    have you checked out qurakdude's youtube post? his engine sounds incredible, and all it looks like he's done to it is install a decent air filter and a boost bottle. so there is proof that they do work correctly... i'm just not sure how. i've applied aerospace grade sealant to pretty much the entire intake manifold/carby/boost bottle area, it'll be dry by tomorrow so i guess i'll have to wait til then to see if it works or not.
  14. nickbk

    nickbk New Member

  15. nickbk

    nickbk New Member

    cool, my boost bottle works. it WAS an airleak, but i couldnt tell you where, since i sealed everything. i think it does help the engine, and i can detect a certain amount of acceleration improvement in the mid-revs, but other than that, i got more performance out of installing a hotter spark plug. still, it looks cool. im happy with it.
  16. Egor

    Egor Guest

    There is no sense in belaying the point. But there is a reason the expansion chamber works and a reason the a Boost Bottle works. None of the criteria has been met on the little Chinese engine. If there is any improvement in the running with or without the bottle it is probably a quincedence. I have been tuning high powered motorcycles all my life, I saw the boost bottle come and go. There was never enough improvement to warrant its use. There is info on the web that enplanes how it was to work, one of the important details was never allow it to trap fuel, all the ones I have seen would hold a full pint. Oh well there still selling them. Have fun, Dave
    PS: I wish you could hear my engine run, with all the porting and carb mods, I think you would like the sound. But it is not about the sound, how well does it pull the bike? Up Signal Hill with no pedal. Quark's bike is nice but it still revs slow.
  17. Egor

    Egor Guest

    Good to hear Nick. I wish I could get you one of my cylinders so you could have a go with it. A two stroke is all in the port and the pipe. The pipe uses a shock wave created from sound, so they have to be tuned to a certain speed to use the shock to move fuel. The distance from the port and the second cone in the pipe is critical, you don't look for sound, its performance but the sound will be there. The boost Bottle uses a shock wave from the reeds slamming shut, the pulse is timed to the next intake, and assists the movement of charge air. On a Dino the increase was so small we left them off. Have fun, Dave
  18. graucho

    graucho Active Member

    I waited to post here until a friend could get access to a radar gun for testing. Tests were run using my silver beast. I weigh 212. Runs were shorter because I didnt want to blow the cheap ebay "boy go fast" engine up. Tests were best at low-end. Diminished at hi-end.

    Test 1. Steep hill 22deg. incline. 200 ft from a dead stop.
    ________________________ No boost______With boost bottle
    _________________________16 mph________18 mph

    Test 2. Flat grade no wind. From a dead stop.
    ________________________ No boost______With boost bottle

    ________________50 ft______11 mph_______13 mph

    ________________100ft _____17 mph_______18 mph

    ________________150ft_____ 21 mph_______ 20 mph

    ________________200ft_____24 mph_______ 23 mph

    Test 3. Flat grade no wind
    slowest speed without the
    ________________________ No boost______With boost bottle

    Test 4. Bike at Idle.
    ________________________ No boost______With boost

    Test 5. Flat grade no wind.
    Hydrogen/oxygen Boosted-
    from onboard hydrogen fuel cell
    Injected through the
    boost bottle intake port.
    (Along with the throttled gasoline oil mixed @ 20-1)
    ____________________________ No boost bottle.
    _____________________________200 ft 30 mph wow! 6 mph faster than above. Hydrogen/oxygen supercharged the fuel.
    Backed-off before I blew her up.

    Attached Files:

    Last edited: Apr 29, 2008
  19. nickbk

    nickbk New Member

    i would concur with your results, graucho. i feel like my bike responds better in the low and mids, but it lacks more than it used to up high. ergh, anyway, im just happy it works at all, and i didnt waste my money on it. now im off to tinker with my new project. will keep you guys posted (i have to teach myself how to weld before i can start it, lol).
  20. croniebones

    croniebones New Member

    Residual fuel in the intake/carb/crankcase. Once it's used up, the engine leans waaay out and dies, a very unhealthy thing for two strokes.