VTEC Starter Valve Synchronization
K&N filter Install
Airbox snorkel modification
Preparation
Remove the tank screws and prop up the tank. Unscrew the 7 screws on the top of the airbox, remove the tube to the flapper.
Remove the airfilter and unscrew the 8 screws on the velocity stacks, lift the airbox out of the way. I had to remove the wire to the flapper solenoid to accomplish this but I did not have to remove any other tubes or wires to lift the airbox up out of the way.
Remove the velocity stacks notice that the stacks are different sizes, they are offset so that the short ones are on the inside and the tall ones are outside. Front tall on the left short on right, back short on the left tall on the right.
Disconnect the hoses to the PAIR Valves front and back
Back
If you have a rubber cap plug up the open ends of the PAIR valve tubes, we did not so we stuffed in a plastic bag.
There are 4 starter valves connected to a 5 way tube connector, they take air from the airbox and bypass it into the intake manifold in place of a choke. They must be balanced by equalizing the vacuum pressure so they run evenly and run smoothly.
Here is a clear view of the 5 way connector
another view
Remove the 4 tubes from the 5 way connector and connect them to your a 4 way vacuum tester, I use a motion pro mercury tool
They are difficult to reach and if you lose them you have to fish them out
make note of the tubes in relation to the starter valve location as they are related. connect the tubes to the number on the vacuum tool
Here they all are connected
Connect an electronic Tachometer
I have a multi use tool that has a built in tachometer
The ECM computer has a tach lead wire that gives off pulses that an electronic tachometer can read, I just shoved the lead in behind the connector, it is the yellow and green wire on the gray connector, and set the tool to 4 cyclinder.
Ground the tool anywhere on the frame
Start up the bike and warm it it up to operating temp. Then set the idle speed to 1200 rpm, Craig's bike was only at 1050 when first measured. The idle adjustment is on the right side
Begin balancing the valves, They are numbered #1 left rear, #2 left front, #3 right rear, and a non adjustable #4 valve at the right front side. turn the valves one at a time to get them all even with #4 and adjust the idle to 1200 until they are all even, clockwise to lower and counter to increase the vacuum pressure.
Remove the tools and reconnect the 5 way connector, replace the airbox and reinstall the velocity stacks.
K&N filter install
Remove the rubber gaskets in the groves of the top and bottom of the airfilter
The K&N has a built in gasket just set it into the groove.
Snorkel Modification
I also have a K&N on my VFR, I was cleaning it last month and found that the filter was dirty only on one side so I cut away a portion of the snorkel to get a more even distribution of air and still get the laminar flow.
I cut the rubber at the first ridge and left the top of the snorkel material, cutting at an angle.
The modification increased my normal tank mileage by 20 miles to a tank of gas extra. But I did not notice a loss of torque at low rpm and a slight increase in power.