October 31, 2013
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WHAT IS IT? Splitstream’s Uni Valve is a crossover tube system for the Kayaba PSF air forks found on the 2013-2014 Honda CRF450 and 2013-2014 Kawasaki KX450F.

WHAT’S IT COST? $89.95.

CONTACT? or (503) 830-6433.

WHAT STANDS OUT? Here’s a list of things that stand out with the Splitstream Uni Valve air-fork system.

(1) Theory. The Uni Valve is a classic crossover air system that combines both fork legs into one sealed air spring. Crossover tubes were commonly used on motocross bikes in the 1970s and have been used on production street bikes since then. With the Uni Valve, you only have to put air into one Schrader valve, and that valve is conveniently located right over the triple clamps for easier access.

(2) Design. Splitstream’s Uni Valve kit comes with a main regulator valve (mounted on a bracket that fits under the steering stem nut), two crossover tubes (with threaded fittings), and two block-off valves that seal the fork caps for maintenance when the red crossover tubes are disconnected.

(3) Quick release. Installing the Uni Valve is a five-step process. First, remove the stock Schrader valves from the PSF forks (with the front wheel off the ground). Second, mount the regulator under the steering nut. Third, disconnect the red crossover tubes from the regulator by pushing in on the special, black release sleeves. Disconnecting the crossover tubes allows them to be threaded into the empty Schrader-valve holes in the CRF450 fork caps. Fourth, take one of the stock Schrader valves that you removed from the fork caps and thread it into the main regulator. Fifth, insert the red crossover tubes back in the quick-release fittings on each side of the regulator.

(4) Air pressure. During testing, riders asked if they had to use 66 psi instead of 33 psi because both fork legs were connected. The answer is no. The recommended air pressure isn’t doubled. It remains the same.

(5) Performance. The big advantage of the Splitstream Uni Valve is that it makes the daily chore of checking air pressure easier. With one centrally located Schrader valve, there is no need to wrestle with the number-plate strap or fork caps. Just fill and go. With the Uni Valve installed the CRF450 handlebars can be rotated forward. Plus, with the Uni-valve we could run oversize bars and move them forward if we wanted. 

WHAT’S THE SQUAWK? Risk. With separate air chambers, you will always have air pressure in one fork leg if something goes wrong. Once you cross them over, you have all your eggs in one basket.

Oh, don’t get us wrong; we give the Uni Valve five stars for ease of use, and every MXA test rider elected to install the Uni Valve on his race bike. We just don’t want to assume you’re willing to take the same risks we are.


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