2015 US OPEN – ROUND # 1 – DALLAS, TX BULLETIN US OPEN – DALLAS - 1 IMPLEMENTATION: MAY 6th 2015 This bulletin is necessary to authorize a temporary modification from the current 2015 USRMC Technical Regulations for the new Electronic Power Valve used with the 125 MAX and 125 MAX DD2 engines. We have been informed by Rotax that the new Electronic Power Valve may not work properly in some conditions, especially where tracks are located in high altitude. They identified the problem and the will introduce a modification kit shortly to solve the possible problem. Because the modifications kits will not be available for the first round of the US Open, this bulletin will allow three mounting possibilities for the event. 1. As described in the current 2015 USRMC regulations. If your electronic power valve is mounted according to the regulation and works perfectly, you may still use this mounting configuration. 2. “Suction mode”: This mode uses the actual parts of the electronic power valve. The only addition needed is a piece of fuel hose. See image on next page: a) Connect the pulse hose of the fuel pump to the black plastic Y splitter (1). The opposite end of the splitter must be connected to the crankcase with hosing as illustrated. b) The side exit of the Y splitter must be connected to the green check valve (2). The arrow on green check valve must point towards the Y splitter. c) The hose from the green check valve must be connected to TOP of the Control Unit (3). page 1 of 3 BULLETIN US Open Round # 1 – DALLAS – 1 th Edition: May 6 2015 3. “Pressure mode”. This mode uses the actual parts of the electronic power valve minus the existing internal spring. This mode uses the addition of a spring (Rotax part # 239 940) and a piece of fuel hose. See image on next page: a. Connect the pulse hose of the fuel pump to the black plastic Y splitter (1). The opposite end of the splitter must be connected to the crankcase with hosing as illustrated. b. The side exit of the Y splitter must be connected to the green check valve (2). The arrow on green check valve must point towards the Control unit (3). c. The hose from the green check valve must be connected to the underside (steel nipple) of the Control unit.(3) d. In the Electronic power valve, the compression spring (Rotax part # 638 050) located under the exhaust valve piston must be removed. Compression spring (Rotax part # 239940) must be installed on the outer side of the exhaust valve piston (same configuration as the pneumatic power valve). page 2 of 3 BULLETIN US Open Round # 1 – DALLAS – 1 th Edition: May 6 2015 page 3 of 3 BULLETIN US Open Round # 1 – DALLAS – 1 th Edition: May 6 2015
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