Author Topic: rpm question  (Read 1373 times)

0 Members and 2 Guests are viewing this topic.

Gittfiddler

  • Guest
rpm question
« on: July 22, 2008, 02:41:05 PM »
I finally remembered to ask this, as I think about it as I ride and forget immediately once off the bike.  so, I'm new to motorcycles and my last air-cooled experiences where with Volkswagen's 15 years ago.  On VWs, you want to keep rpms moderately high to keep air flowing for cooling and never lug in a higher gear.  What is the best rpm range for around town riding as that is majority of the riding I get?  When is the most heat being developed and what range is the least stressful on the engine?  I hope this makes sense and I'm posting in the right spot.  thanks

Offline TwoTired

  • Really Old Timer ...
  • *******
  • Posts: 21,805
Re: rpm question
« Reply #1 on: July 22, 2008, 02:58:59 PM »
You have to wind the 350's pretty tight for them to make power.  They like it.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline MJL

  • Don't listen to me, I'm no
  • Expert
  • ****
  • Posts: 1,162
  • Oh hell, what's one more bike?
Re: rpm question
« Reply #2 on: July 22, 2008, 05:03:33 PM »
My 650 I stay over 3000, preferably over 4000. It seems to like that for both acceleration and compression braking. My 750 I usually run a little lower, over 2000.  It's nice to keep the rpms low but still have power to get up and move without downshifting.
« Last Edit: July 22, 2008, 05:05:22 PM by MJL »
No matter how fast or how far I rode, I couldn't leave her memory behind.

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: rpm question
« Reply #3 on: July 22, 2008, 05:10:00 PM »
I finally remembered to ask this, as I think about it as I ride and forget immediately once off the bike.  so, I'm new to motorcycles and my last air-cooled experiences where with Volkswagen's 15 years ago.  On VWs, you want to keep rpms moderately high to keep air flowing for cooling and never lug in a higher gear.  What is the best rpm range for around town riding as that is majority of the riding I get?  When is the most heat being developed and what range is the least stressful on the engine?  I hope this makes sense and I'm posting in the right spot.  thanks
I think the issue with the VW was to keep rpms high enough that the engine driven fan would make a difference to the engine heat, without going too fast or too much load and heating more than the fan could handle? (Did it have an engine driven fan?)

If so its not a sideways comparo to our bikes which have no fan. You just want to run them appropriately for the load and weather. All things in moderation as the Greeks would say. Not too much you can do really but keep moving forward at moderate plus engine speed. Buts if youse gots to go, youse gots to go!   ;D
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Gittfiddler

  • Guest
Re: rpm question
« Reply #4 on: July 22, 2008, 05:38:43 PM »
engine driven fan was what I meant so the comparison isn't quite parallel but that is my experience with air-cooled.  ultimately with my stop & go riding, what is best for my engine (750)?  Is heat the enemy, and am I creating more chugging a little or at higher rpms?

Offline MJL

  • Don't listen to me, I'm no
  • Expert
  • ****
  • Posts: 1,162
  • Oh hell, what's one more bike?
Re: rpm question
« Reply #5 on: July 22, 2008, 06:07:07 PM »
I think a better question is how do you know if you are overheating?

If you think about it, 4000 rpms is burning twice as much fuel as running at 2000 rpms. More fuel = more heat...   But I wouldn't lug it.
No matter how fast or how far I rode, I couldn't leave her memory behind.

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: rpm question
« Reply #6 on: July 22, 2008, 06:21:40 PM »
engine driven fan was what I meant so the comparison isn't quite parallel but that is my experience with air-cooled.  ultimately with my stop & go riding, what is best for my engine (750)?  Is heat the enemy, and am I creating more chugging a little or at higher rpms?

To me, the average operating range is 3500 to 6000. Below that is lugging, above is not necessary unless you're trying to prove something.

On a really hot day, keep to the lower rpms without lugging if you can't keep the forward motion up (stop and go traffic). If you're moving along consistently rev it up more.

Engineers try to design for all contingencies. But a really hot day (90+ Faren) in stop and go, may call for a pullover once in a while. But I remember once in AZ going N to Phoenix at 105+ Faren, at speed the side wind blowing through the engine heated my leg past comfort. Not much one can do in the extreme, pulling over wasn't any cooler than keeping moving, at least for me.

A lot of hi temp stop and go would call for more frequent oil changes. I think.
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Gittfiddler

  • Guest
Re: rpm question
« Reply #7 on: July 22, 2008, 07:22:21 PM »
I try to keep a range of 3000-5000 and I don't want to prove anything other than cutting across parking lots to avoid ligthts ;)  the uncomfortable heat off the engine is a common occurance but my commute it less than 3 miles to my shop.  i just want to treat her right.  yes, the better question is when and in what range do I run the risk of overheating.

Offline MCRider

  • Such is the life of a
  • Really Old Timer ...
  • *******
  • Posts: 14,376
  • Today's Lesson: One good turn deserves another.
Re: rpm question
« Reply #8 on: July 22, 2008, 07:35:31 PM »
I try to keep a range of 3000-5000 and I don't want to prove anything other than cutting across parking lots to avoid ligthts ;)  the uncomfortable heat off the engine is a common occurance but my commute it less than 3 miles to my shop.  i just want to treat her right.  yes, the better question is when and in what range do I run the risk of overheating.

With a 3 mile commute, you've got a bigger worry in rusting out your exhaust pipe from condensation than overheating.   :D
Ride Safe:
Ron
1988 NT650 HawkGT;  1978 CB400 Hawk;  1975 CB750F -Free Bird; 1968 CB77 Super Hawk -Ticker;  Phaedrus 1972 CB750K2- Build Thread
"Sometimes the light's all shining on me, other times I can barely see, lately it appears to me, what a long, strange trip its been."

Offline Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: rpm question
« Reply #9 on: July 23, 2008, 05:51:46 AM »

If you think about it, 4000 rpms is burning twice as much fuel as running at 2000 rpms.


That's not really true.  At 4000 rpm the engine is creating a lot more torque so you don't need to have the throttle open as much as you do at 2000 rpm and the same speed.