Ignition cover. We keep cracking ignition covers horizontally across their face. Originally, we replaced the cracked covers with new ones. This was stupid, because the new ones would crack also. Eventually, we became experts with JB Weld and just patched up the cracks. The oil leak is minor, but frustrating.
Shock linkage. The 2009- 2011 CRF450s stinkbug. Our best solution was to swap out he stock 144mm shock linkage for a Pro Circuit 146mm link. The Pro Circuit link lowers the seat height and stiffens the ini- tial part of the shock’s stroke (but does not affect the end of the stroke). Once you get the rear end lower, you can fiddle with the fork height to find a head angle that suits your track conditions. This is a must-do for anyone serious about taming the Honda’s overly aggressive handling.
Engine/tranny oil. The big plus of Honda’s separate engine oil system is that owners can run a low friction oil in the engine and gearbox oil in the transmission. The downside is that the quantity of engine oil is greatly reduced when compared to Kawasaki, Yamaha, Suzuki or KTM’s shared oil supply. Plus, it requires carrying two different ypes of oil with you. MXA just runs high-quality four-stroke ngine oil in both parts of the CRF450 engine. We don’t get the full benefit of the dual chambers, but we don’t have to worry about which oil we put where. Putting low friction-style oils (with moly) in the tranny would kill the clutch in short order.
Exhaust system. In their desire to meet the AMA’s 94 dB sound level requirement, Honda went all-out. Not only did they increase the muffler canister’s length by over four inches, but they reduced the perf core’s diameter by 10mm. The good news? The 2011 Honda CRF450 is whisper quiet. The bad news? All that restriction kills low-end throttle response. Every aftermarket pipe we tried added horsepower and moved the peak up. Incidentally, every aftermarket pipe was AMA-legal.