This is why every SR/TT/XT500 needs a Twin Feed Oil Line:

The KEDO Twin Feed Oil Line provides oil supply to both rocker arm axles, rocker arms, the camshaft and valves directly via the hollow bore of the respective axle, thus reducing wear and improving cooling of the entire valve train. Depending on the year of manufacture, the original oil line only supplies the input or output rocker arm axle directly with fresh oil, the other side is supplied indirectly by the oil in the cylinder head cover. By reducing the operating temperature, a lower valve clearance (0.08/0.13mm instead of 0.1/0.15mm) is possible, resulting in quieter engine running. Extended valve adjustment intervals are possible. The original rigid oil line is susceptible to vibration damage - with all our Twin Feed Oil Line Kits we use high-temperature resistant, flexible oil lines with adjustable connections. The KEDO Twin Feed Oil Line is available in three types in several designs and is suitable for all SR400/500, TT500 and XT500: "Raceline"=without aluminium distributor block, "Classic"=with aluminium distributor block, concentrically connected oil line, "Vintage"= aluminium distributor with cooling fins, oil line connected on the side.