Very, very sorry to ask a question about...

Can't Skyliner70cc hurry up and move to sea level (where I live) to continue his unbiased research?!?!?

It must be very poor form to try to open another thread about boost bottles, and I apologize....yet I'm still typing!

It seems that they tend to NOT increase top-end performance (which I don't care about) but DO help with low-end performance (which I AM interested in). Starting and idle quality are certainly not a priority. I simply want to "broaden the power band". Any improvement under load or RPMs below it's high-rev sweet spot are longed for. I'm considering a 48t vs the current 44t, but don't want to lose top end either.

I was aghast at the plumbing seen with these kits...thread-in nipples?!?! How can they possibly not inhibit air in-flow with that length of pipe thread sticking down into the airstream?!?!? Has anybody done any welding onto these aluminum (I assume) manifolds? Something along the lines of a plumbing sanitary Y fitting welded on, so there is nothing sticking down into the airflow, nor a sharp 90* bend for "boost gas" to try to flow through, but rather a gradual angle for the "pressurized backwave" to go more readily flow into boost bottle than out the air filter?

Aside from quarkdude and Autocycler (no offense please, I already know your stance) does anybody else have positive comments or real world actual measurements of performance? My mental prowess of logical analysis is siding with Bikeguy Joe, but I want more opinions than the 6 or 7 guys that have previously voiced opinions. Specifically regarding sub-sweet-spot-rpm performance.

Hmmm, no response.

I know people either love 'em or hate 'em. Maybe the low end boost is not what some are looking for and never even realize it's there?

Have you matched the exhaust port/gasket, and cut out some of your baffle? Both help the low end.

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If it ain't broke, and you mess with it long enough, it will be.

I did grind out the manifolds to more smoothly flow, as well as the exhaust gasket. But nothing to the exhaust. Where/how much?

I still have mine on cause it looks cool, and dont want to go thru the trouble of soldering the manifold closed. The vendor sent me the wrong manifold, and rather than wait an additional week I soldered in my own nipple in using 5/16 copper. Mine is not aluminium it is chromed steel. I silver soldered the nipple using propane making sure it did not protrude into intake airflow. I have gone out riding with the bottle and have pinched it off to try to see any benefit and cannot see any. I have matched my intake and exhaust ports and that made such a differnece I had to move needle to full rich inside carby. Next will be exhaust mod and hopefully thats it.
My 2 cents worth.....

Take your muffler/intake off, take a exhaust gasket and put it on engine, then carefully cut out the gasket to match exhaust/ intake port on engine (careful not to get shreds inside engine). When done take the gasket off being careful not to turn it around or turn upside down, then put it against manifold/ muffler and see how much metal needs to be removed. Trace with a marker then just match gasket wit a dremel, which in return matches intake/exhaust. My muffler blocked the exhaust port on the engine by at least 25%, prob 15% blocked on intake...

This is heresay only------------------ A boost bottle helps at high altitude with midrange, and acceleration.
NO improvement at sea level.
I dont use one.
I have enough intake leaks as ir is.
Fifty two feet ftom you know where.
Sealevel.

OOps, I wasn't clear...i already ground out intake/exhaust. Not much change in performance. The where/how much was referring to the muffler baffle.

I have to disagree with the hearsay as I grew up in the early 70s on 2 stroke street and off road MOTORCYCLES and have had excellent improvements with boost bottles, and have always lived at sea level. Now these have been considerably larger displacement from 125cc to 750cc and have been with boost bottles that were made by reputable people, in the racing industry, such as White Brothers. There may be an improvement, but when you are talking about 48cc and you get an improvement how much can it be? As for air leaks installed properly this should not add to any air leaks that you have, and to be honest you shouldnt have any, especially with all the posts available to correct them...

never be sorry for asking questions. it is the reason i started this forum was so we could learn from each other

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I have a boost bottle on my off-road rc truck...it enhances the low end, not top end. I believe I can see a difference - only in acceleration, but I think it works. I would try one...who's selling them?