VFR Air Fork Equalization

My '86 VFR750F has forks that you can pressurize with air (between 6-11 lbs.) to help dampen them. Of course, it is imperative to get the pressure equal between the two for optimum safety and performance, such as it is.

I remember hearing about (and I think seeing) a simple device that was basically an air-crossover that equalized the pressure between the two tubes. It was a small semi-rigid plastic hose that attaches to two metal pieces that screwed on the existing valve stems on top of the fork tubes, one side of which also had a standard air valve allowing you to add air to both tubes at the same time in an equal amount.

Does anyone know where I could find such a beast? I'm sure they are out there, and if not as a kit perhaps as just parts? Anyone?

And yes, I know a lot of people with a similar setup on their bikes run with 0 psi in their forks. That wasn't the question...so while I appreciate your willingness to help, please don't use that as an answer. Thanks!

 

I know my old zuki had that type of set up,

Not to be a smart aleck but how about a tire guage? that way you can tell what the PSI is thats what I do. but a cross over would be helpfull..... must try and engineer one......

while I'm thinking about it take a steel braided line 8 inches of so have a valve installed at the half way point and get 2 valve stems for either end....voila' a cross over


BTW nice ride...

 

Look into the dual tire pressure guages used for dually trucks. They can fill two tires at once to the same pressure.

 

This link may help

Dual-Guard

Or this to fill it

Tire Pressure Gauge Equalizer, from Equal-Air Inc.

Also contact Imperial Supplies LLC they can probably provide you with the parts to build your own

 

Personally I would go find 2 cheap air pumps you like the ends on cut the hoses and splice them together with air tight fittings.

 

Lockhart Phillips used to make a fork air pressure crossover kit for the '86VFR forks. I couldn't get one myself,but I saw one once,it was simple enough so I just made it. I took the fork air crossover system off my '86 before I sold it,unfortunately I dropped the air pressure guage and broke it. All I have left now are the fork caps. I'm surprised they were still in my aluminum scrap box. I gave the stock fork caps to my buddy Steve for reference,and had him machine the custom fork caps that you see here. I arranged them in the picture the way that they used to mount in the fork tubes. A small low pressure air guage screwed into the upper hole of the left fork cap. An air filler valve screwed into the upper hole of the right fork cap. A small air fitting screwed into each of the lower holes on the fork caps. A plastic hose slid onto a steel tube that protruded from each of the small air fittings. A brass ferrel and a steel nut secured the plastic hose to the air fittings. That's exactly how the Lockhart Phillips system worked,simple as that. I sourced the air guage,fittings,and plastic hose from a pneumatics supply store. The air guage had a bleeder valve so you could pump a little more air pressure than you needed into the forks and slowly bleed down to the exact pressure that you wanted to run. I used to run 10psi. I always set the fork tube air pressure with the front end off the ground and unweighted on a triple clamp lifting style bike stand. The readout on the fork mounted air guage would always read higher than my 10psi setting once the bike was lowered to the ground. The nice thing about having the fork mounted air guage was that at a glance you could tell if you were losing any air pressure in your forks. Sorry I don't have any pictures of the kit mounted on the bike JohnnyM,I never took any. Hopefully you get the idea of how it worked from my description.

 

My VF500F was the same deal. It's more important that they're close than perfect, I actually tried one fork tube a half a PSI off. I felt no difference. But yeah, when I had my VF500F I was a part of the 0 PSI club most of the time. The rear shock is the one that needs to actually have pressure, however balance is easy there's only one.

I would pick up a cheap digital pressure gauge from walmart. They're about 8 dollars and accurate to .1 psi (I have one, works like a champ).

Plus, I would think leaving the hose attached would cause the problem of fork oil switching from one fork to the other (even though the pressures on compression would be equal, where the fork oil is is not). Plus if you detach it you'll probably lose more air in one fork than the other which may offset it more than the inaccuracy of a gauge, unless you had a means of releasing the shrader valve needle before you detached the hose.

Ride more, worry less!

 

BOOM! Found exactly what I was looking for, and it cost about the same as buying the parts and making it from scratch would:

Progressive Suspension Air Fork Balance Kit

 

Score!!!

Yep,that's the stuff JohnnyM. That kit uses the exact same concept as the set-up I used on my '86. Good Luck with that.