? evo engine

[copemech]

Think you need to get the flyweight off, as you said it WAS there?

These seem to be remarkably smooth and tractable bikes, and put into practice, few mere mortals complain. Yet there are mods trhat can perk one up. And at the same time sacrifice other traits.

[steve fracy]

The V-Force reeds are a mandatory addition! What a difference through the entire range! Get a hold of Ron Commo in the US and he will set you up!!

[copemech]

The V-Force reeds are a mandatory addition! What a difference through the entire range! Get a hold of Ron Commo in the US and he will set you up!!

How the hell would you know! Duh!

[dan williams]

V-force reeds are the first mod I do for a new Beta but they don't really "perk it up". They do make it pull much better in the lower RPM like when I'm in the wrong gear because of mid-section brain fart.

[quert]

V-force reeds are the first mod I do for a new Beta but they don't really "perk it up". They do make it pull much better in the lower RPM like when I'm in the wrong gear because of mid-section brain fart.

cheers you guys had it out at weekend after checking out and doing some of the things you said and !!!! Rides like a different bike !!! just me to sort now a few mid section brain farts !!!!

and a few slack dabs and second !!!!!

[vgstef]

The V-Force reeds are a mandatory addition! What a difference through the entire range! Get a hold of Ron Commo in the US and he will set you up!!

What is the main difference with the V-force ? Is it more snappy ?

Thank you

[dan williams]

The V-Force reeds are made out of carbon fiber so they have less mass which means they will open and close faster.

At high engine speeds all reed valves are essentially stuck open as there is constant high velocity airflow through the intake. In this situation the design of the reedcage is the limiting factor as it acts as an obstruction to the airflow. At mid engine speeds the reeds really don't serve much purpose. They will actually pulse without fully closing and this is where the spring tension of the reed comes into play as there is some spring to help them close but too much leaves them partially obstructing the airflow. Reed valves are really all about performance at low RPM. A piston port engine is stuck with fixed port timing. The transfer and intake ports have to be open for an extended part of the crank rotation to not starve the engine for air at high RPM but at low RPM mixture will escape back out the inlet tract. The dreaded "Four Stroking". The reed valve is intended to cure this by replacing the intake port with a pressure sensitive valve that closes when there is back pressure in the intake of the engine which at low RPM happens every stroke. As with any piece of material flapping back and forth its mass is going to determine how much force is required to change its direction. Since the carbon fiber is extremely light weight it will respond to smaller changes in air pressure faster than a comparable fiberglass or steel reed.

OK end of diatribe. In short lighter weight reeds react faster so the bike will have more torque at low RPM. This translates to grunt like an old fashioned trials engine while still maintaining the shoulder ripping burst of a handful of throttle on a new bike. Boyesen multistage reeds accomplish the same thing in fiberglass by having a smaller light weight reed along with a larger heavier reed for big throttle moments. Great for MX but not really enough room or need for that much complexity in a trials engine.

If you put in a set of V-Force you won't immediately go WOW what a difference. But the first time you blow a shift before a tricky uphill and crawl up it in third and the bike just keeps chugging you'll appreciate them no end.

[vgstef]

The V-Force reeds are made out of carbon fiber so they have less mass which means they will open and close faster.

At high engine speeds all reed valves are essentially stuck open as there is constant high velocity airflow through the intake. In this situation the design of the reedcage is the limiting factor as it acts as an obstruction to the airflow. At mid engine speeds the reeds really don't serve much purpose. They will actually pulse without fully closing and this is where the spring tension of the reed comes into play as there is some spring to help them close but too much leaves them partially obstructing the airflow. Reed valves are really all about performance at low RPM. A piston port engine is stuck with fixed port timing. The transfer and intake ports have to be open for an extended part of the crank rotation to not starve the engine for air at high RPM but at low RPM mixture will escape back out the inlet tract. The dreaded "Four Stroking". The reed valve is intended to cure this by replacing the intake port with a pressure sensitive valve that closes when there is back pressure in the intake of the engine which at low RPM happens every stroke. As with any piece of material flapping back and forth its mass is going to determine how much force is required to change its direction. Since the carbon fiber is extremely light weight it will respond to smaller changes in air pressure faster than a comparable fiberglass or steel reed.

Thank you

OK end of diatribe. In short lighter weight reeds react faster so the bike will have more torque at low RPM. This translates to grunt like an old fashioned trials engine while still maintaining the shoulder ripping burst of a handful of throttle on a new bike. Boyesen multistage reeds accomplish the same thing in fiberglass by having a smaller light weight reed along with a larger heavier reed for big throttle moments. Great for MX but not really enough room or need for that much complexity in a trials engine.

If you put in a set of V-Force you won't immediately go WOW what a difference. But the first time you blow a shift before a tricky uphill and crawl up it in third and the bike just keeps chugging you'll appreciate them no end.