boost bottles: yay or nay?

[nickbk]

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.

 

[sparky]

http://www.motoredbikes.com/showthread.php?t=6603

That thread should give you a better idea. I haven't done it yet, but I can't say that I've read anything bad about it.

 

[Large Filipino]

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.

 

[nickbk]

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?

 

[Demosthenese]

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.

 

[nickbk]

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.

 

[Alaskavan]

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).

 

[nickbk]

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.

 

[Alaskavan]

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.

 

[misteright1_99]

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....