Many BMW Twins from the 80's and 90's have a great deal of tubing and plumbing underneath the fuel tank. This starter cover makes it possible to tidy things up, reduce weight and complexity. Before performing any of the modifications described below, check with your local and State authorities to determine if you are legally permitted to remove emission related equipment from your bike. This cover will essentially allow you to convert your bike to German specifications of that era.
There are up to three systems housed in the air filter housing and starter cover:
To stay in line with US exhaust emissions regulations, BMW developed the secondary air system (SLS). This system has vacuum operated pumps inside the air filter housing that inject filtered air into the exhaust ports causing after burning in the headers, which incinerates the unburned fuel vapors. This system accounts for the steel tubes that run between the heads and the air filter housing and also the vacuum tubes that attach to the carburetors. This system drastically increases the exhaust temperature and accelerates wear of the exhaust valves and guides.
The other system that is attached to the starter cover is an electronic fuel shut-off valve. This is in place so that the flow of fuel is stopped when the ignition is turned off, so in theory, you don't need to turn your fuel petcocks off when stopped or, if you forget, there is an added measure of safety. The downside with this system is that fuel flow is reduced and the fuel has to follow a more complex path. The result is evident when you run low on gas and you switch to reserve, it takes a long time for enough fuel to reach the carburetors and that can be dangerous in traffic! By eliminating this system, the fuel flow is vastly improved and the carbs are quickly filled when switching to reserve.
The Third system relates to fuel tank venting and it initially only affected California spec bikes. The system consists of a solenoid valve that is shut when the ignition is turned off. Fuel vapors are then trapped in the fuel tank and crankcase with this system and not allowed to escape into the atmosphere when the bike is parked. Once the bike is started again, the valve allows the fuel vapors to flow into the intake system, where they are burned by combustion and then once more by the SLS system. The negative side of this system is that the fuel vapors being stored in the crankcase lead to premature break down and contamination of the engine oil.
In summary; although these systems were designed with good intentions for the environment, each of them in their own way have a negative impact on the longevity and / or safe operation of the bike. The weight savings is also considerable.
Now we'll get to the point: if the above mentioned systems are disabled and the valves and other components removed, the original starter cover resembles Swiss cheese with all those holes and our starter cover gives your bike a clean uncluttered and original appearance. We sourced a number of nice, undrilled used starter covers in Europe and brought them home. These have been stripped and powder coated black. Then the raised "BMW" was meticulously ground, giving a matte finish, just like factory. These reconditioned starter cover may have some slight imperfections where the cables rubbed on them, etc. but they are very, very nice and a great improvement if your bike has one of the aforementioned starter covers. This part is no longer available from BMW
Additionally, you will need the following parts:
** For the ultimate and perfect conversion, we also offer reconditioned used lower airbox housings that were never drilled in the first place! These were also imported from Europe and reconditioned. If you want your bike really sanitary and as close to perfect as possible, then in addition to this starter cover, you'll also want the lower airbox housing.