Author Topic: sustained rpm (Read 5943 times)

kpier883 · « **on:** October 09, 2007, 06:39:07 PM »

I am planning a 700 mile (each way) ride on the '74 CB750 starting next Sunday. I think that 75 mph is about 5800 - 5900 rpm. 80 is around 6000. I am trying to make the trip each way in one day - Birmingham to Dallas, then back a few days later.

With gas stops every 120 miles or so, this would be a pretty long day at 65 mph.

Do you think that I should slow it down, or are these motors okay with 10 hours at almost 6k rpm?

Right now I have 15w40 Chevron Delo. It is not the LE or low emission oil, so it has the higher zinc content.

I am not trying to start an oil thread, so I only mention the oil so that it can be factored into your responses to the rpm question.

By the way, I can't confirm the actual mileage on the engine, but the odometer shows almost 17,000 miles.

Kirk

Bodain · « **Reply #1 on:** October 09, 2007, 06:43:27 PM »

Go back in time. The year 1969... The CB 750 was introduced... I recall a motorcycle magazine doing a write up on it. Naturally the front cover had a pic of the CB 750 on it. The headline attached to the pic reads " At 100mph it's not even breathing hard!"
Well it is beathing a bit at 100 mph, but it was a great line at the time.

736cc · « **Reply #2 on:** October 09, 2007, 07:05:31 PM »

80 mph all day no problem

Jonesy · « **Reply #3 on:** October 09, 2007, 07:13:32 PM »

In keeping with the bike mag theme, I recall one referring to 5,800 RPM as "loafing"...

kpier883 · « **Reply #4 on:** October 09, 2007, 07:21:02 PM »

Thats what I was hoping to hear.

I will hope that the better oils available today will make up for the extra 30 years, and that 80 mph will still be "loafing".

I did three 500+ mile days this summer mostly going 75 to 80, but was just thinking that maybe I was pushing it a bit.

Thanks for the feedback.

paulages · « **Reply #5 on:** October 09, 2007, 07:51:52 PM »

honda also did 24 hour tests at redline, if i'm recalling correctly, with no failure.

Steve F · « **Reply #6 on:** October 10, 2007, 05:35:19 AM »

It should be fine......remember, a good quality oil is most important. Something that won't break down easily in the sustained heat.

andy750 · « **Reply #7 on:** October 10, 2007, 05:49:49 AM »

Ive done a few long distance trips with sustained high rpm riding for many days/months continuously and my CB750K4 has always performed. One example is a USA cross-country trip - 16 days, 5400 miles - mixed riding - deserts, mountains, highway. Or European Alpine tour - lots of mountains - 6000 miles/16 days. As others have said no problem. If your doing 700 miles in one day with no windshield (as I do) then it will take around 11 -12 hours so plan accordingly. And you will be very tired as well

Good luck,
Andy

MRieck · « **Reply #8 on:** October 10, 2007, 06:19:52 AM »

Quote from: andy750 on October 10, 2007, 05:49:49 AM

Ive done a few long distance trips with sustained high rpm riding for many days/months continuously and my CB750K4 has always performed. One example is a USA cross-country trip - 16 days, 5400 miles - mixed riding - deserts, mountains, highway. Or European Alpine tour - lots of mountains - 6000 miles/16 days. As others have said no problem. If your doing 700 miles in one day with no windshield (as I do) then it will take around 11 -12 hours so plan accordingly. And you will be very tired as well

Good luck,
Andy

You are freak'n crazy.

andy750 · « **Reply #9 on:** October 10, 2007, 06:24:34 AM »

See you on Saturday for the Fall Ride (unless the Nor`easter really is coming!

)

cheers
Andy

Tower · « **Reply #10 on:** October 10, 2007, 09:10:44 AM »

It isn't the bike not holding out for ten solid hours, that I'd be worried about, it would be finding a good chiropractor afterwards.

kpier883 · « **Reply #11 on:** October 10, 2007, 09:20:12 AM »

Quote from: MRieck on October 10, 2007, 06:19:52 AM

Quote from: andy750 on October 10, 2007, 05:49:49 AM
Ive done a few long distance trips with sustained high rpm riding for many days/months continuously and my CB750K4 has always performed. One example is a USA cross-country trip - 16 days, 5400 miles - mixed riding - deserts, mountains, highway. Or European Alpine tour - lots of mountains - 6000 miles/16 days. As others have said no problem. If your doing 700 miles in one day with no windshield (as I do) then it will take around 11 -12 hours so plan accordingly. And you will be very tired as well

Good luck,
Andy

You are freak'n crazy.

Andy - Yes it is without a windshield. I will plan for 11 - 12 hours - thanks.

Current plan is to leave around 5:00 AM and arrive 5:00 PM. Sunday traffic at 5:00 PM in Dallas should not be a problem.

On the 500 mile days I have noticed that noise is a contributor to fatigue. I have not found comfortable ear plugs. Typicall I just wad up some bathroom tissue and stick it in my ears. I am very "high tech" in matters such as these

.

kpier883 · « **Reply #12 on:** October 10, 2007, 09:29:11 AM »

Quote from: Tower on October 10, 2007, 09:10:44 AM

It isn't the bike not holding out for ten solid hours, that I'd be worried about, it would be finding a good chiropractor afterwards.

Prior to hitting the road for my first long trip on this bike, I was mostly worried about the bike making the trip.

40 miles into that trip I remember being very worried - but mostly about me being able to hold out. I think being nervous was causing my back to cramp up. Also, the grips were not very comfortable and my gloves had a seam that was bothering my hands.

After the first tank of fuel was burned and we stopped for a refill I kind of relaxed and the next 300 miles were fine. However, I never did really get comfortable with the gloves and had to switch hands from time to time to let my right hand relax. In the 80's I rode a lot using my left hand on the throttle, but I got out of the habit and now it makes me kind of nervous. The front brake master cylinder makes a nice place to rest the right hand and adds some feeling of being in control when working the throttle left handed.

6adan · « **Reply #13 on:** October 10, 2007, 09:47:48 AM »

When I got out of the Navy in 1970 I rode from San Diego to Alabama in four days.In Arizona and New Mexico I would just turn the throttle to the stop and hold it there till I had to stop for gas,no problem. I knew next to nothing about bikes at the time,I did not even oil the chan but the bike did have that automatic oiler. Dannie

kpier883 · « **Reply #14 on:** October 10, 2007, 11:11:15 AM »

Quote from: 6adan on October 10, 2007, 09:47:48 AM

When I got out of the Navy in 1970 I rode from San Diego to Alabama in four days.In Arizona and New Mexico I would just turn the throttle to the stop and hold it there till I had to stop for gas,no problem. I knew next to nothing about bikes at the time,I did not even oil the chan but the bike did have that automatic oiler. Dannie

Now THATS a good story.

tsp37 · « **Reply #15 on:** October 10, 2007, 05:56:01 PM »

I know a girl who drove a VW Jetta from Tennessee to Phoenix in 24 hours. She put a whip to that pony. She is a few years older and a mom now, and her driving has slowed considerably.

andy750 · « **Reply #16 on:** October 11, 2007, 05:35:20 AM »

Driving a car and riding an unfaired bike are completely different experiences. After riding the bike, driving a car is like a walk in the park

\

cheers
Andy

paulages · « **Reply #17 on:** October 11, 2007, 02:21:54 PM »

Quote from: tsp37 on October 10, 2007, 05:56:01 PM

I know a girl who drove a VW Jetta from Tennessee to Phoenix in 24 hours. She put a whip to that pony. She is a few years older and a mom now, and her driving has slowed considerably.

i've done drives like that dozens of times on tour. definitely not the same as being on an unfaired bike. (but still brutal.

)

kpier883 · « **Reply #18 on:** October 11, 2007, 05:34:55 PM »

Ok. While riding today I checked my earlier statements about rpm. Actually, 75 mph was closer to 5200 rpm. 80 mph looked to be about 5500 - 5600 rpm, so 6000 rpm would have been more like maybe 90 mph.

jevfro · « **Reply #19 on:** October 11, 2007, 06:17:31 PM »

Quote from: kpier883 on October 09, 2007, 06:39:07 PM

Right now I have 15w40 Chevron Delo. It is not the LE or low emission oil, so it has the higher zinc content.

Just a word of warning... It is my understanding that chevron changed their Delo formulation a year or two ago, and in doing so adding a fair amount of Moly. Molybdenum can cause problem w/ wet clutches like ours.

I'm not starting an oil thread I promiss!

Oh yea I switched to Shell rotella T 15w45 (still cheap but no moly)

Bob Wessner · « **Reply #20 on:** October 11, 2007, 06:39:41 PM »

OK, I'm not trying to encourage an oil thread, but I have noticed in the past a number of members running other than the originally suggested 10w40 weight oil. Now I can see in hotter climates someone using 10w50 weight, but why would one use an oil with a higher winter rate (i.e., going to 15wXX rather than staying with 10wXX)? It would seem that a lower viscosity would be helpful in getting oil pumped around faster at lower, cooler temps during start-up.

Bob Wessner · « **Reply #21 on:** October 12, 2007, 10:24:42 AM »

No takers, eh?

Seriously, not trying to discuss mineral vs synthetic, or brand, it was intended as a viscosity question, specifically the low temp end.

750essess · « **Reply #22 on:** October 12, 2007, 10:40:45 AM »

I run 20w-50 in my 836, cause when it gets hot the oil pressure drops to about 5 psi at idle. Runs about 10 with the heavier stuff. I dont ride in the cold anyways.

kpier883 · « **Reply #23 on:** October 12, 2007, 10:47:04 AM »

I'v been told the 750 motors run forever no matter what oil is used

. I have an auto oiler for the chain. I mainly use the 15w because it sticks to the chain much better than 10w.

dusterdude · « **Reply #24 on:** October 12, 2007, 10:50:42 AM »

bob,in order to run diesel oil to get no moly,you have to use 15w40.i dont think there is a no moly 10w40 out there.

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Author Topic: sustained rpm (Read 5943 times)