Anyone ever try the boost bottle idea of having an external extra combustion chamber after the carbureator? Iv seem it in the dirt bike world just didn't know if anyone had played w this.

It works, my Crown Reserve works wonders. I give me a shot right in the carb intake adn it hits the combustion chamber really quick. Don't help my shootin though.

Just had to do it sorry man. If there is enough venturi vacuum to support the needed charge it could and probably would work. Its main purpose is to give a better on throttle response and low end torque/hp. Probably won't see more than 10 hp out of the addition though.

Curl

That's what I was thinking, have u seen anyone put a divider in the carbureator to direct the flow, separate the top and bottom where the air circles

I have on a few high performance 2 clcle engines. I think the fact that they spin up so quickly, they draw more intake volume. Not sure the big 4 stroke Briggs can do that without some sort of supercharger set up. Ne t gain is not worth the effot to me. Once we have modded with cam, timing, carb, air flow, exhaust back pressure, etc, not much else other than velocity stacks or NO2 will be worth the effort.

Curl

I doubt they will hold the addiitonal cylinder pressures.

Yea i see. I was thinking of the boost bottle theory for my motor it would be something I could do myself really wo altering much

I misunderstood your original post. The boost bottle is to keep the air/fuel mixture in a a 2 stroke engine cylinder and to stop it from exiting the reed and going back into the carb then back into the cylinder. THis richens the fuel too much. I really dont see a benefit on a 4 stroke when you have valves that control when fuel enters and exits the cylinder.

I see the rich part bt the stored gases would give a quicker shot of compressed to the cylinder giving more response on the jump

I honestly don't think it makes THAT much of a difference. If it was really cruicial it would be alot more common.

Pretty common in the two stroke and 4 stroke dirt bike business

Not much for the more hp it's more abt the throttle response. Engines are engines

A little read i found.
http://www.raptorforum.com/forums/showt ... hp?t=57937

There's no doubt it works on 4 strokes. Here at my machine shop te guy installed one on his 4 stroke and it woke it up coming out of a turn after throttling down, he explains it as when he gets back on it seems to turn up rpms quicker. Guessing the stored mixture is closer to the piston giving u quicker injection

It basically gives you a larger intake volume without the side effects of having a longer/lower velocity intake tract.

huntingsmith, I built several different versions of bore dividers for the mikuni and I didn't notice a damn thing. I made them with varying lengths and placed them higher and lower in the bore of the carb btwn the carb and intake. IMO you have to have a much faster flow to notice their effects. Something like a 2 or 4 stroke dirt bike. Alot of mods are definitely specific to a given motor or application. You''ll see that when you start experimenting with various mods. What works for one motor doesn't do squat for the next.

Yippee, that's a lot of what we talkd abt at the shop w the air flow being much faster on 2-4stroke dirt bikes compared to v-twin. Just wanted to see if guys had tried this b4 and what the results have been

Look up( scary fast) they make.a.divider for Harley bikes useing the 45 mm
mikuni. Helps bottom end and smooth idle. Don t know if they make them for 42 mm carbs


JD