CB1100 assymetrical cam timing, lift, and duration.

[LakeWylieJoe_imp]

I think the service manual indicates the intake lobes on cylinders 1 and 2 open the valves 10 degrees after cylinders 3 and 4. I can verify this if you'd like. They also vary the fuel and ignition timing some as well. Let me know if you want the link to the Honda development story page. The idea was to give the engine "rumble" at 3,000rpm, which roughly translates to the national speed limit in Japan in top gear (100k/h). It's not meant to alter the balance of the piston/conn-rods/crankshaft, just to make it feel a little more like the unrefined air-cooled 70's in-lines... It bugs me a bit--wish they would have just left the timing the same on all cylinders. The rumble seems to go away when you really get cooking. Same thing for low speeds.

Shoot me an e-mail if you want the shop manual specs or the link to the CB1100 development page that talks about the design goals and details: josephnorris0106@yahoo.com