Boost Bottle in Operation

[happycheapskate]

http://motorbicycling.com/picture.php?albumid=531&pictureid=7057

My bike fell over a couple times, and the first time nothing happened but mashed my bottle. I "popped" it back out by inflating it slowly with a bicycle floor pump. The 2nd time, the bottle was ok, but the plastic engine cover and heat shield were a little damaged. Still works ok though. Tanaka parts are expensive.

Are you using a friction drive system, too? I located the steel bottle on the engine cover by rubberizing the bottle and zip-tying it to the vents. That worked, but it gets in the way of the starter handle a little. You can locate it on the top of the drive channel, but don't make the hose too long. You could also use flat-stock to make a bracket or 2 to go between the stock tank and engine bolt bosses, to extend for a place to hose-clamp the bottle to.

Whatever you use for a bottle, be sure that it can withstand high heat (summer heat, engine heat, sun exposure), and can be trusted not to leak. (fuel spray leak is dangerous, air leak will kill the engine or make impossible to start. That is why engine manufacturers don't design with them included. More liability for them)

 

[16v4nrbrgr]

I was thinking an empty Ronson butane bottle.

 

[happycheapskate]

You can do that. That's where I got the idea for mine (the axe fragrance can).

Buy this: http://ecx.images-amazon.com/images/I/31i42mEq9kL._SL500_AA300_.jpg

1/4 hose inside diameter double ended brass barb coupler. ($2 at Home Depot or Lowes)

and this:

http://www.overstockdrugstore.com/product_images/h/079340815018.jpg
Loctite Quick Set 3200 PSI Epoxy syringe.

and this:
http://2.bp.blogspot.com/_aLVdG3xTpZY/ScAaJ0S0pmI/AAAAAAAABBs/NhiKYHll3S0/s320/shaving+cream.jpg

cheap shaving cream can

Use the foam for something fun, like letting your kid spray it like silly string. hahhaha.
Yank out the plastic tube under the spray button, and drill it through with a small bit, then a larger bit just slightly bigger than the barb. A rat tail file also works. Wash out the can and dry it in the oven to make sure its absolutely dry.

Put a cotton ball or paper inside the brass barb. Now epoxy the heck out of that thing, to glue it into the can. Try to get it straight as you can. With the barb plugged, you can hold the can upside down and press the barb in until it sets. (don't glue your finger!)

Remove the paper with a drill bit or coat hanger. If you have to, drill through, carefully. You can expand the hole slightly but don't over-do it or it will crumple and twist up on the running drill bit or the bit will seize.

The ronson can can work, but be careful as the can is sold containing a flammable liquid and residue obviously.

You can also use a soup broth can. You will have to waste the broth because you don't want to eat drill shavings.

 

[happycheapskate]

Here's one from Ronson can, done with soldering iron, solder, and brass tube.

http://www.youtube.com/watch?v=lHBeYe8jg48

There are similar Ronson and other brand injector refill cans (pressurized aerosol lighter fluid), of sizes around 30cc.

 

[biknut]

I've read discussions on moped boards where the common belief is that little 50 and 65 cc motors are too small to benefit from a boost bottle.

 

[scotto-]

I think the main question about a boost bottle that's never been adequately answered is, does it suck, or does it blow?

Gravity sucks and wind blows........this we know for sure!

 

[happycheapskate]

Gone over the same thing a bunch. Little engines have a lot to benefit from a vacuum bottle. They don't blow anything. They contain a vacuum pulse which smooths out the engine cycle.

 

[16v4nrbrgr]

Yeah basically give the intake air a place to go for a millisecond while the port is blocked by the piston so the fuel stays atomized and the bottle adds a "boost" to the next cycle versus the air just stopping and reversing, with the atomized fuel redepositing inside the port and on the side of the piston.

 

[scotto-]

Gone over the same thing a bunch. Little engines have a lot to benefit from a vacuum bottle. They don't blow anything. They contain a vacuum pulse which smooths out the engine cycle.

Here's one for you, see if you can figure this out.

I've been playing with and making boost bottles for several of my Tanaka 2-strokes over the years. One of my Tanaka 47R's had a bb on it that was made for about that size engine 47cc. The engine ran exceptional with the bb installed and ran fine as well with out one. Here's the puzzle; with the engine sitting still idling, you could pinch the tubing that connects the bb to the intake manifold and it would kill the engine. The tubing was silicone surgical type. Why would this stop an idling engine?

 

[happycheapskate]

Could be couple things. If you adjusted the idle throttle position or idle mixture after installing the cannister and modified mani, it will die because the system mod helped it idle lower/ at different A/F mixture.

If you didn't adjust the carb, it is likely because movement or pinching of the line caused an air leak at one of the barbs.

 

[scotto-]

After installing a bb, the first thing to do is lower the idle speed and fatten the mixture just a hair. There was no air leaking from anywhere when I pinched the tubing closed. I have also found that using longer and fatter surgical tubing gave better performance as it would pulse itself and really smooth the engines running. Better throttle response as well.

 

[happycheapskate]

I used rubber fuel hose and worm clamps on mine. The vinyl hose tended to dry out and not seal well on the barbs. I use it for makeshift fuel line sometimes on mowers, and it never lasts. It turns hard and yellows.

If you mean the latex rubber "slingshot band" type surgical tubing, then I don't have experience with that. Seems too fragile to use for fuel lines. (vacuum cannisters use a fuel line in a sense, bc. air and fuel move through it.)

I dug up my Boost Bottle (TM) from my happytime bike project I dissassembled. It is much smaller in volume than my Axe can bottle. I will try it sometime and see what if any difference it makes.

 

[scotto-]

I used rubber fuel hose and worm clamps on mine. The vinyl hose tended to dry out and not seal well on the barbs. I use it for makeshift fuel line sometimes on mowers, and it never lasts. It turns hard and yellows.

If you mean the latex rubber "slingshot band" type surgical tubing, then I don't have experience with that. Seems too fragile to use for fuel lines. (vacuum cannisters use a fuel line in a sense, bc. air and fuel move through it.)

I dug up my Boost Bottle (TM) from my happytime bike project I dissassembled. It is much smaller in volume than my Axe can bottle. I will try it sometime and see what if any difference it makes.

I had the best results with dozens of boost bottle applications using pure silicon tubing. It swells like macaroni when left immersed in gasoline, but works great when attached to a bb.

Also, an air leak won't kill an idling engine if it's not too excessive, It would lean the mixture and make it idle much higher if anything. I honestly can't say why pinching the tubing causes the engine to die, I just found it very interesting that it did. Not many types of tubing would allow you to pinch completely shut by squeezing between your thumb and forefinger only.

 

[happycheapskate]

I'm guessing that at idle, the pinched line disrupts the pulse that draws on the fuel jet, so on the stroke that doesn't get enough fuel, it just dies.

I'm going to start calling them pulse bottles. Vacuum is just not as attractive to say. hahaha, and they don't "boost" anything like NOS or something that little kids mistake it for.

 

[scotto-]

I'm guessing that at idle, the pinched line disrupts the pulse that draws on the fuel jet, so on the stroke that doesn't get enough fuel, it just dies.

I'm going to start calling them pulse bottles. Vacuum is just not as attractive to say. hahaha, and they don't "boost" anything like NOS or something that little kids mistake it for.

Yes it really is all about the pulse and lessening the effect of negative or reverse resonance. When done right however, you will notice a substantial increase in performance and a slight hp gain. Nothing mind boggling as some people claim. That's all I got, never tried one on a 4-stroke......no need