Shorty intake

Josh_wilcoxx

Member
Joined
Jun 4, 2019
Messages
70
I put a shorty intake on my bike yesterday, and man I did not expect such a big difference. Previously I had one of the shorter offset intakes on in hopes to be able to fit my air filter, but still wouldn't fit. Still ran that filter for a while, you can see parts of the frame where the paint was completely taken off. But, I switched to the short intake, and oh boy, my powerband is much more usable now. Noticed more torque, and higher speeds. And on top of that, freshly and thoroughly cleaned carb inside and out, and a fresh filter. It looks good, and works great.
 

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Mark 1971

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Joined
May 30, 2021
Messages
38
Nice! I recently read a 171 page article about 2strokes. The shorter the intake the better the powerband. I am considering a shorty myself.
 

Street Ryderz

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Joined
Oct 14, 2016
Messages
3,956
When running with a muffler rather than a tuned pipe you may notice improvements in power within the rpm range but there is no powerband, intake length due to the pulses can be tuned somewhat to the intake timing but has no real effect on the powerband as the powerband 2 stroke engine builders refer to comes from a tuned pipe over filling the cylinder within a certain area of the rpm range. A short intake is actually better suited to higher rpm engines.
 

YetiWoodz

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Joined
Dec 19, 2019
Messages
1,097
A short intake is actually better suited to higher rpm engines.
Does it make the intake pulse enter the cylinder when the port is fully open so it doesn't create a choke point?

Thus making these true....?

A shorty at low rpms would make the fuel come in when the port isn't yet opened all the way.

A long intake at high rpms would make the fuel come in when the port is already partially closing.
 

Street Ryderz

Well-Known Member
Joined
Oct 14, 2016
Messages
3,956
Does it make the intake pulse enter the cylinder when the port is fully open so it doesn't create a choke point?

Thus making these true....?

A shorty at low rpms would make the fuel come in when the port isn't yet opened all the way.

A long intake at high rpms would make the fuel come in when the port is already partially closing.
as with anything with pressure changes the vac pressure is highest when the port first open's, but max velocity is just shortly after then starts to revert as the piston finishes the up stroke and comes back down. This reversion pushes a/f charge out of the case back towards the carb and on a short intake has enough flow to pull fuel again from carb and saturate the air filter, where with a longer or tuned intake this reversion can be trapped in the intake adding to the next charge somewhat.
 
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