White Valves and Top Caps

[rkjjeep]

Some of you know I've been messing with the vacuum plumbing and the white vacuum valves on the top caps of my 2006 F.  Summing up what we know so far:  The engine control unit takes throttle position, RPM, and maybe gear position into account and decides whether to command the vacuum valve on the bottom of the right carb to supply vacuum to the white valves.  When that vacuum is supplied, the white valves allow a bit of air at atmospheric pressure into the cavity on TOP of the slide diaphragm.  This has the effect of LOWERING the slides a bit.

I really like the way my bike is running with pilot mixtures screws set at 3 turns and one shim under slide needles.  Stock exhaust and intake.  Today I disabled the white valve system to see how it would run.  To disable the system remove the vacuum supply line to the valve on the bottom of the RH carb and plug it with the right size screw.  It is the OUTBOARD vac hose on the solenoid.

It is not dramatic but the bike rides better without the system being active.  Most noticeable is improved response in top gears at mid RPM's.  For example, with the bike in 5th gear at 50MPH response to light throttle is MUCH better.  It also takes a little less throttle to maintain speed in 5th and 6th.

This is very easy to try - if you don't like it take the screw out and plug the hose back on to the valve under the RH carb.  Both hose removal and re-connection can be done from the rt side of the bike without removing anything.

Before anybody gets all bent out of shape about the emissions - remember that these systems are engineered and installed so the bike can pass the EPA driving cycle test.  The bike is set up on a dyno and the exhaust gases are run thru an analyzer.  The tech rides the bike and follows a trace on a computer screen.  Some starts and stops and lots of light throttle accels.

I don't have the time or equipment to confirm this but I'll bet the fuel economy is as good as or better and the real world total emissions are probably no worse.  To get the same response you'll be messing with the throttle a LOT less.  I will check a couple tanks for mileage.

Has no effect on idle and seems to have no effect on WOT - just the mid throttle light throttle application stuff.

So now I'm looking for a couple plain no valve carb tops to see if they fit.

Peace!

[twinrat]

thats great keep us all informed so we can all make improvements . my experiment for the weekend was to fit blanks on the pair valve inlets and removed pair valve completly ,fitted another vacuem canister in its place  now i have 2 vac tanks [ results ] bike feels stronger in low to mid range .have ridden it over 36 miles and feels stronger .others should try this and get there opinions onto here.i will try white valves coming weekend.


do it yourself be sure its done right

[rkjjeep]

I don't think anyone ever figured out if the vac reservoir was required for the vac petcock to avoid fuel starvation or if it was added so that there would be enough vacuum available to run the slide lift valves (the white valves).   

The PAIR valve removal is a piece of cake.  Do ebay search for pair valve block off plates for OLDER Hayabusa.  Look at the pair fittings on front of head - you'll recognize the correct block off plates.  Then you just remove everything, install the block off plates, and cap the vacuum that was running the valve.

My objective is to simplify the bike as much as possible.  Less chance for vac leak, less clutter, less waste, less intervention by an emission control system that was designed to pass a test completely unrepresentative of how most people ride. 

[rkjjeep]

Rode the bike around tonight in a more controlled situation, with and without the "lift valve" vacuum hooked up.  It's a subtle difference but the bike is more responsive to light throttle application and requires a little less throttle to maintain speed in 3-6 gear at mid RPM.  Suzuki must not have needed to drop the slides much to meet the regs.  If you know electronic systems this is known as an open loop system.  Data from sensors is considered, a map is "consulted", and the slides are dropped a bit (or not). 
I'll be removing the whole shebang from my bike in a few weeks - more info then. 

[rkjjeep]

OK - finally got it done.

I replaced the aluminum diaphragm covers with the white valves with plain old black plastic ones part number 13502-07F00.  I did order and install the small o-ring under the covers even though it appears to do nothing.

I removed the vacuum solenoid from the bottom of the right carb and tied the short lead from the bike harness back so it would not hang down.

Most of the vacuum hoses went away.  I have a vacuum hose going from the vac port on the right carb to the petcock and I teed the vac reservoir into that.  Probably don't need the reservoir but as long as it doesn't leak it can't hurt.

I installed a 20 pilot jet and shimmed the slide needles with one shim.  Remember that I had previously tried the bike with and without the white valves being actuated and found that it ran better.  The mixture screws are set at two turns with the 20 pilots. 

The bike runs perfectly.  More responsive, stronger mid range, pulls 3, 4, 5, 6 gear better.
After playing with the mixture screws it's looking like the bike did not need the 20 pilot - I'll put the stock ones back next spring.

Bottom line - You CAN get rid of all the crap, clutter and potential vac leaks on top of the carbs.

A cheaper way would be to just remove the solenoid and all the plumbing and cap everything off.  I wanted the cleaner look of the plastic caps.