jcstokes wrote on 08/06/15 at 13:41:15:The consensus around here seems to be that it's difficult to over rev the engine and that a tach isn't necessary.
A tach helps to establish a proper idle speed, and it does give you an indication of what rpm you are traveling when cruising - but beyond providing that information the tach really isn't a necessity. After a bit you learn to shift by ear and by the seat of your pants.....you can feel when the bike is running out of "juice" and needs to be shifted into the next gear.
You are not likely to hurt the engine by revving it up in each gear and then shifting it to the next.....you can feel the engine "top out" and stop pulling at high rpm - and it is time to shift. Don't hang out at that high rpm for a sustained period.....shift to the next lower gear!
I do believe that you can potentially thermally overload the engine by sustained idling in traffic. Sitting in heavy traffic in hot conditions doesn't get any airflow to the engine, and the oil will become thin and the oil pump cannot pump the thin oil well. At idle with the thin oil a lot of the oil will go to the bottom end, and little will be pumped to the cam bearings or be splashed up on the piston. The cam bearings or piston skirt will most likely be the first parts damaged.
During sustained high speed running the engine tends to get hot, and the piston expands and may overheat and score the piston or cylinder. The engine also tends to lose a lot of oil during high rpm cruising. There have been several members that have ruined a piston/cylinder while cruising down the interstate at 80-90 mph for sustained periods. At least one was a result of running the engine oil too low during the ride. I don't think anyone has reported problems when cruising at 70 mph or less.
Pages: 
