do 85 V-Boost tubes is 30mm while 1986 and above is 32mm?

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uri gal

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I heard that VMAX'S of year 85 have V-Boost tubes is 30mm while 1986 and above have 32mm?

This true? What is the meaning of that ? less power? More power?

In this days I am importing a 85VMAX from USA… so if I need to fix something… now is the right time J
 
I heard that VMAX'S of year 85 have V-Boost tubes is 30mm while 1986 and above have 32mm?

This true? What is the meaning of that ? less power? More power?

In this days I am importing a 85VMAX from USA… so if I need to fix something… now is the right time J

It is true- the exhaust was changed after '85 to lower the sound decibles too.
 
what is the effect on the power in the change from 30mm to 32mm

You open her throat a bit more above 5750 RPMs. Im inclined to say that more flow implies more power as long as the exhaust allows for it.
 
The 86 intakes were made larger to offset the quieter/more restrictive exhaust so the Horse Power would remain the same, 145 HP @ the crank.
For the States, this model brought the following changes: The diameter of the V-Boost tubes was increased from 30 mm to 32 mm. The non-DOT approved exhaust canisters are corrected to be compliant.
From here:
http://www.vmaxguru.com/Tech/Gen1/Pages/History/Gen1_History.htm
 
anyone ever measure the stage 7 tubes. that replace the v-boost butterflies ?
are the bigger,smaller or stock size ??
 
My thought is that the Stage 7 tubes are probably fractionally larger than the cast aluminum VBoost butterfly casting. Not enough to make any real discernable difference in everyday use. Remember that a smaller diameter in the intake usually boosts torque, where larger diameters boost HP. Where do you spend 95% of your riding time? Also, what about the diameter of the intake castings which bolt to the head? If they are smaller than the Stage 7 I.D., the increase in the tubing isn't going to help, and may in-fact hinder smooth airflow. Abrupt changes in diameter cause a disruption of airflow along the sides of the passage (laminar flow), and this turbulence can negatively affect the passage of air/fuel.
 
anyone ever measure the stage 7 tubes. that replace the v-boost butterflies ?
are the bigger,smaller or stock size ??

33.25 mm inside. Plus there is no throttle plate/butterfly. The difference is slight, but with a few other tweaks?
It all adds up.I might try the tubes. It' a bit of a hassle to sync.
 
My thought is that the Stage 7 tubes are probably fractionally larger than the cast aluminum VBoost butterfly casting. Not enough to make any real discernable difference in everyday use. Remember that a smaller diameter in the intake usually boosts torque, where larger diameters boost HP. Where do you spend 95% of your riding time? Also, what about the diameter of the intake castings which bolt to the head? If they are smaller than the Stage 7 I.D., the increase in the tubing isn't going to help, and may in-fact hinder smooth airflow. Abrupt changes in diameter cause a disruption of airflow along the sides of the passage (laminar flow), and this turbulence can negatively affect the passage of air/fuel.

now you got me thinking.
so smaller tube increase torque. making for quicker launches. or bigger tubes for HP on the big end?
should the intake castings be polished for smoother flow?
is it worth the time to flow match intake castings and stage 7 tubes ?
should all of the above be as smooth as possible. or rough'n them up to help fuel and air to mix ?
My 250r fourwheeler had carb work. that had smooth areas for air to enter the carb. then got rough to mix fuel and air.

it's the little things .That make big differences
 

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