Some time before the move I ordered up an Exhaust Plumbiing Alternative (EPA) Kit from Bob’s BMW and promptly tossed the kit in Strix’s tank bag and forgot about it. On the way back from the BMW MOA rally in Springfield, MO I felt like the bike ran poorly and the fuel economy was worse than I was used to with Otus. When I got home I tucked the bike into the shop and went about recuperating from the heat. A few days later I was unpacking the bike and rediscovered the EPA kit in the tank bag. It was time to get to work!
The “pollution control” stuff installed at the factory consisted of pipes that connect the cylinder heads to the airbox. Removing these pipes and installing the kit itself was easy enough but to get everything cleaned up I had to get into the airbox to remove and plug some vacuum hoses. Once I was inside the airbox I realized that the fuel delivery plumbing was also overly-complicated so I decided to simplify that as well. Under the starter cover there were two “solenoids” of some kind that the fuel passed through. These were connected to the fuel tank and carburetors through a maze of fuel hose. With the starter cover off I was able to remove the solenoids and sinmplify the top of the fuel delivery plumbing. The most challenging part of the reconfiguration though was adding a crossover fuel line like on Otus. To get the crossover fuel line added I had to remove the airbox entirely. This proved to be a challenge until I figure out how to get crankcase vent tube. With that, and the associated pieces out of the way I was able to remove the airbox, add the crossover fuel line, and button everything back up. I even used the appropriate Airhead braided fuel line when re-plumbing the entire setup! Now it looks like a proper Airhead. A turn of the key and a press of the starter button and Strix came alive, and sounded much better!
While I was able to execute this project to near completion with the parts I had on-hand (the EPA kit, Airhead fuel line, and fuel tees) the EPA kit provided screws to plug the vacuum ports on the carburetors. Unfortunately the vacuum ports on Strix’s carburetors were not threaded so I had to order up a vacuum plug kit from my friends at Amazon to complete the project.
As the saying goes, pictures or it didn’t happen. Unfortunately I’m a bit rusty and I didn’t get any before picture. I do, however, have a couple of after pictures that show what got removed and the neat and clean fuel line plumbing that makes Strix look like a proper Airhead!