Do Boost Bottles Work?!

I'm going to put a b-bottle on my Tanaka33 today. I got some Instant Epoxy (one of those syringe types that mixes it in the needle. I am going to cut sections of bic pen outer plastic tube for the fittings (no threads!) and drill a nice hole in the riser block, at a little bit of an angle for venturi effect and clearance. I'm making a bottle from a small medical bottle and another ink pen tube section. I will upload pics or video later this week.

Right now it is facing a bit upward and it's 66cc and I forget how many ounces the bottle is but it's equivalent to about 68cc's. And I've got about 7-8 Inches of hose. And yes it did feel it need to be rejeted, I felt yesterday like it just wasn't getting fuel. So I'll try again sometime this week.

So much for this week, I DID IT TODAY! So I rejeted from a #68 to a #70 and it changed quite abit, plus I relocated the boost bottle so it faces downward. The results weren't too bad. I got good low and mid power but my top speed still isn't what it used to be, it's better but not the same. With no wind I could hit 33-34 and with a tail wind 36MPH. So I'm still short 3MPH but I guess it's not to bad atleast I've got a little better torque I can't complain much.

I've got the holes drilled, 1 in the carb spacer, and 1 in the bottle I'm using, for the plastic tubes. That carb spacer is made of wood! I guess it's treated or laquered, but still surprised that it's WOOD. I think it might be some kind of resin with wood particles. The intake air channel starts as a rectangular hole and funnels into a small round hole.

It is best to drill small holes and step up to the next few sizes, to avoid "chunking" (when the hole cuts poorly or the bit takes a big bite and chunks the part at you, then you chunk it in the garbage and sulk while parts ship).
Or worse, taking a chunk out of your fingers. Careful! Use a bench vise!

The pieces are assembled, waiting overnight for the parts to set (used Loctite instant mix epoxy syringe. Be careful with that stuff! whoo!).

Here's hoping this works! I accidentally tore the factory gasket (carb-to-spacer), so I have to cut one (fel pro synthetic material). This Tanaka thing is not the easiest to get stuff for, already found that out.

I wouldn't give $300-400 for this motor (asking price on lots of scooter sites), but for $100 its smashing! (amazon find)

I have built the boost bottle, from a Tea Tree Oil bottle from the pharmacy. It is a very thick glass. I drilled the lid carefully, with several bits, up to a 5/16" bit. The pen tube fit in very tightly. I put epoxy in the cap, so it would seal the pen to the lid, and the lid to the bottle. Then I wrapped it in a few wraps of electrical tape. I expect to mount it to a rubber radiator hose which acts as the air intake tube. (1.75" wide velocity stack). If that doesn't look well, I'll make rubber straps with a "pocket" for the bottle, which wrap around the gas tank. Then it will be safely away from the hot parts, and the pull cord.

The carb spacer came out very well, with the hole angled nicely , and the pen tube syringe cut and mated flush with the inside air tunnel hole walls. The inside edges of the pen tube were beveled with a pocketknife before installation.

I am waiting now to finish with the carb spacer gasket, then I will be able to test run the bike and make a video. Photos to upload later when I find my USB cable.

If the engine is very new, you may be able to carefully separate the pieces, and re-use the original gaskets. I tore the engine-to-spacer gasket and have to cut one now. UGH. (ordered from O-reillys. Cutting gasket will be a PITA)

I finished with the boost bottle installation. The bike ran fine. It idled a little high, till I backed off the idle stop screw 1/2 turn. The bike started easily and ran smoothly, idled fine, even to a much lower RPM, smoked less at idle, and pulled hard at RPM it's usually not useful for. I didn't have to pedal much with it, even towing my baby trailer. The bottle is about 60-70cc, glass with plastic lid epoxied on with tube epoxied in 1/4", and with a 1/4" hose the minimal length needed to ziptied the bottle above the pull start cover, on the shroud vents (6" approximately).

http://motorbicycling.com/picture.php?albumid=531&pictureid=3570


I improved upon this by using a rubber 26x2.1 bicycle tube section instead of electrical tape for wrap, and adding mini-zipties to the hose connections for extra security (they were on tight but for a few ct. , of mind).

I learned this from r/c boat builders.

Sweet looking setup Happy!

Na,,
Just something else to vibrate loose...if you want boost,,a port,polish,and proper tune would be much better IMO.

My vacuum bottle works great. It pulls hard up hills and really smooths out the engine especially at low RPM.

The glass bottle was discarded in favor of a steel can (see my user pics).