Homemade ram air intake=WOWPOWER!

Darkwolf

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Oct 16, 2018
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So after dealing with the annoying higher rpm four stroking capping my 80cc China girl rpm range I got creative. I know it's caused by rich conditions of the stock main carb jet, i had already done some backyard tweaks by shaving the head, swapping a bosch platinum 2 plug from my old impreza which intrudes into the combustion chamber upping compression and allowing for better spark, and deleted the baffle in the muffler, and being a mechanic I know there's 2 ways to fix a rich burn... decrease fuel or increase air! Well after about 20 minutes I made this abomination... and holy hell what a difference! I gained way more rpm and eliminated the four stroking problem! I kid you not I was passing cars in a 35mph zone where people drive 40 or higher regularly!

Feeling creative and experimental? Try it!
20181016_153742.jpg
 


NOLA Rider

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Feb 8, 2014
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How well does it work? I did something similar to mine and made a huge difference. I would recommend using a CNS carb so you can adjust the air mix from your handle bar as you ride.
 

Street Ryderz

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Oct 14, 2016
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How well does it work? I did something similar to mine and made a huge difference. I would recommend using a CNS carb so you can adjust the air mix from your handle bar as you ride.
There is no ram air for a 2 stroke,it's an open venturi that allows better flow from not having the restricted filter housing.The CNS carb's second cable and thumb lever on the bars is an enrichment valve used as a choke but instead of restricting air to increase the amount of fuel entering it pulls fuel directly from the bowl and put's it in the air stream after the metered flow through main body.There is no change in air delivery as you add fuel with this valve.
 

Darkwolf

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Joined
Oct 16, 2018
Messages
17
How well does it work? I did something similar to mine and made a huge difference. I would recommend using a CNS carb so you can adjust the air mix from your handle bar as you ride.
It works amazingly well! Took it for a 40 mile ride today and rode past one of those radar signs that says "your speed is ____" on a slight incline and was clocked at 36mph which is way better than before... if hit 35 on a decent downhill descent.
 

NOLA Rider

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Feb 8, 2014
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Almost everything I've read says that ram-air doesn't have much affect, if any. Guys that know their engines inside and out explain why it doesn't work. But can anyone tell me why it could theoretically work? There has to be something to it because multiple people (myself included) trying it say they have had a noticeable difference. I'm genuinely asking for an explanation other than "it forces air into the carb". Anyone?
 

Street Ryderz

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Joined
Oct 14, 2016
Messages
3,007
Almost everything I've read says that ram-air doesn't have much affect, if any. Guys that know their engines inside and out explain why it doesn't work. But can anyone tell me why it could theoretically work? There has to be something to it because multiple people (myself included) trying it say they have had a noticeable difference. I'm genuinely asking for an explanation other than "it forces air into the carb". Anyone?
Ram air doesn't work for a 2 stroke because the intake pulse is actually a vacuum and it's timmed duration is a function of the piston and the port.The improvement noticed is due to the now open venturi witch helps with velocity due to no restriction that the air filter housing creates.No ram air is affective until a certain velocity is meet,that velocity is attained at speeds from 60+ so in reality ram air doesn't work at slow speeds anyway,And because a 4 stroke use's a full down stroke with the intake valve open for intake it allows the ram air to increase that velocity being drawn in.The 2 strokes intake pulse is short and fast,as the vacuum created by the up stroke(below the piston) meets atmospheric pressure it creates velocity through the carb body and the open venturi just allows the max available air to be used in that short burst.
 
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