As I understand it, running an intake tube of some sort forces the air to reach a higher velocity as it enters the carb and intake. The momentum of the mass of air aid's in the scavenging effect and sort of precharges the intake for the next intake cycle. You are indeed getting more air in the cylinder with the same ammount of fuel. But then again, I really don't know what the hell I'm talking about! lol.

 

Let me guess. You stayed at a Holiday Inn Express last night. [img]i/expressions/face-icon-small-happy.gif[/img]

 

got back from a ride yesterday and that tube had me all worked up 150 wasn't enough and all i had was a 160 after that. that thing makes a hugh difference.

 

I run the TM45 with the tube,like stated above I have a 150 main jet.[img]i/expressions/face-icon-small-happy.gif[/img]

 

when i first jetted for the intake tube and open airbox i was making full throttle runs at 80mph on my road, and the forced air through the front snorkel holes seemed to cause me to be leaner at full throttle than I was at trail speeds. whether this was forcing more air into the intake, or decreasing vacuum acting on the main jet, I do not know and it doesnt matter, cause I was definitely leaner at full speed than I was low speed full throttle riding. it was winter, 20 degrees outside, and the main I needed for this arrangment was 162.5 - but this proved a bit rich for trails at low speed, resulting in excess soot.

After installing two 90 degree pvc elbows on the snorkel holes, mounted in the factory rubbers, this elliminated the forced air at high speed, and also makes washing more convenient. the main jet moved down to 157.5, and jetting was good everywhere regardless of speed, gear, or rpm.

Now that spring is here and the temp is back up, I'm down to 152.5
this is all at sea level.

 

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