07-12-2022, 07:29 AM
(07-12-2022, 06:55 AM)The ferret_imp Wrote: Do rpms hurt motorcycles? Ridden within reason NO.
Each engine component has only so many cycles in it (bearings, rings, valves, cam chains, cylinders etc). You can use the cycles up fast or you can use them up slowly.
The average MotoGP race where motorcycles are run at maximum rpms for most of their life is 70 miles long. They run 18 of these races a season plus practice and qualifying. That computes to 1260 miles of racing plus maybe another let's say 4,000 miles in practice and qualifying or approx 5,000 miles total. They are allotted 7 engines to last the season. If high rpms didn't wear out engines, why would they need 7 engines to go 5,000 miles?
I've ridden 68,000 miles on my CB1100 and it still starts and runs great. Is it because it is made with more durable materials? Assembled with more care? Or is it because it has been stressed less and run at fewer rpms? Say 4,000 rpms max vs 18,000 rpm max. I dunno ......
I like to think of engines as hearts. The Chinese used to say that a mouse and an elephant get the same number of heart beats in their lifetime. A mouse at 600 beats per minute uses his up very quickly, while the elephant at 30 beats per minute uses his up very slowly.
Something to think about
A lot of wisdom in your post.
If I recall correctly, 5000 RPMS on the 6 speed was about 100 MPH.
3500 RPMs about 70 MPH.
With HP (86 or 88?) rated at 7500 RPMs, no need to take it to 8500 redline unless a dire situation arises...such as pulling out in front of a truck.
I think redline, if it had a tach, is about 7000 RPMs on my 942 cc Bolt.
If I shift at or before 35, 45, 55 and 70, I will not exceed 6000 RPMs.
The other day I took it to 40 MPH (~6300) in first to evaluate a new K&N air filter. No difference. I took it to ~6200 RPMs once in 5th to learn top speed.
I think it was very rare for me to hit even 6,000 RPMs on the CB.
It just was not necessary. Rolling at 70 MPH in 6th, a roll-on without down shifting would result in 105 MPH from passing a couple big rigs on a remote desert 2 lane.
On the Bolt, cruising at 80 MPH is 4300 RPMs I rarely exceed 5000 RPMs
Bottom line, using quality oil, changing it per recommendation or earlier, I would expect over 100,000 miles on the CB motor, regularly cruised 2500 - 3500/4000 RPMs and rarely exceeding ~6500 RPMs (~75% of redline).