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View Full Version : Liquid R reed stuffer...to mod or not to mod?



DixiePlowboy
04-13-2010, 12:49 AM
(Stock cages and Boyesen Power reeds on both machines I mention)

I noticed that my son's '85 R had the plastic reed stuffer opened up so that when looking in the intake tract from the carb side, there was no plastic protrusion. It had been smoothed to match the rubber intake boot diameter.

Mine has a serious amount of plastic sticking out into the airway.

I understand volumetric efficiency and the whole volume vs. velocity thing, that's why I am not completely removing the plastic "stuffer", but, I wonder if there's any good to be had from essentially....port-matching the intake boot and the stuffer.


And no....I can't swap out with my boy to see if there's a difference(that would make it too easy...:))

TeamGeek6
04-13-2010, 03:54 PM
I took it out (86 R). Your talking about fine tuning/mods that require a flow bench to verify. The change is small. Volume versus flow. Its about optimizing both, not just one or the other.
Compared to the volume of the crankcase and under the piston crown, its a tiny change as far as volume.

If that piece is ground out to match the tube, its not of much consequence, flow is mainy in the center and into the reed petals. Flow is not good on the surface of a pipe due to turbulence.

"Mine has a serious amount of plastic sticking out into the airway."

Them Japs knew how to design hot engines, and there are other ways a lot more effective to get big power gains than that plastic gimmick. I found it, and now on a stock
bore and stroke cant use 1st - 3rd gears. The power just blows the rear wheels off.

Yamahondaman
04-13-2010, 08:47 PM
HA HA ................. back in the 80's i had like 15-30 of them thing's on a string that i took out along with them Roost Boost Gimmick's.....
ALL ATV-ATC'S like BIG Volume... trim and radius the boot as nice as you can without making it too thin...try it and check it out

DixiePlowboy
04-14-2010, 04:25 AM
HA HA ................. back in the 80's i had like 15-30 of them thing's on a string that i took out along with them Roost Boost Gimmick's.....
ALL ATV-ATC'S like BIG Volume... trim and radius the boot as nice as you can without making it too thin...try it and check it out

Remove the stuffer or port match it to flow with the boot -to-cage? I reading your comment as "ditch it". I know it's a small difference either way, but us po folks gotta get a half-horse where we can...lol:)

Bryan Raffa
04-14-2010, 08:03 AM
I say ditch the stuffer... every polaris 400 I touch.. I pull the stuffer out...makes em Rip!

Yamahondaman
04-14-2010, 10:13 AM
Take it out and hang it on the wall ... don't throw it away... spare thing's are hard to find

DixiePlowboy
04-14-2010, 04:41 PM
Good deal. Thanks ya'll.