What engine mods are allowed in ultralight weight endurance? Cams, pistons, gaskets, valve jobs, air box mods,, etc? Purchased a bike and want to make it the best bang for the buck but not illegal. What are the limitations for engine mods? Any other things to look for? Master cylinder? Been out of racing for 10 years.
Superstock trim...so not much you can do re: engine.. n) The OEM air box must be used and an OEM type filter must be properly installed (a K&N style direct replacement filter is an acceptable OEM type). The only modification allowed is the sealing of airbox drains. Filters may be changed. OEM type must be used. If the filter acts as part of the airbox housing the replacement filter must not have a larger opening than stock. o) If the crankcase ventilation hose is relocated from the airbox it must be routed to a catch can and the stock airbox hole must be plugged. p) Spark plugs may be changed to aftermarket parts. q) Clutch may be changed to a slipper clutch. Clutch fiber and metal plates may be changed to aftermarket. Clutch Springs may be changed. r) Cam timing is allowed via the slotting of cam sprockets. Press on cam sprockets may be changed to OEM spec bolt style. Ignition timing may be altered by slotting the ignition trigger mounting plate or by replacing the stock ignition rotor with an aftermarket rotor. s) 1mm Overbores are no longer allowed on any machine manufactured after 1995 (model year 1996 and up) unless offered by the manufacturer as a maintenance item. Aftermarket non-OEM valve seats are not allowed. Head and base gaskets may be replaced with aftermarket parts and do not need to be to stock spec. Aftermarket gaskets may be utilized on engine parts. Multi-angle or radius valve jobs are allowed as normal maintenance as long as machining is confined to the actual valve seat insert and does not extend into the port or combustion chamber. Valve seat to port blending is not allowed. Valves must meet OEM specifications. t) No bead blasting (or blasting using any other medium) is allowed on any internal engine part except gasket surfaces. u) Machining of gasket surfaces of cylinder head(s), cylinders, and engine cases is allowed through 2015 models. 2016 and newer models are allowed surface machining of the cylinder head gasket surface only. All internal and external engine parts must remain stock without modifications, no addition or removal of metal is allowed, except as mentioned in this chapter. No surface treatments are allowed. Engine must remain at stock displacement except as outlined in above. v) The transmission must use the stock OEM parts for that model. Shifter return or detent springs may be replaced with aftermarket springs.
I don’t see why you would want to do cams, pistons or anything to the motor for endurance racing. The goal is endurance, not a sprint. The risk of having a mechanical is extremely high.
