Author Topic: In which gear do you reach 60 mph? (Read 5282 times)

aminemed · « **on:** January 21, 2018, 11:07:27 AM »

Trying to figure out if my bike settings are good, can you let me know in which gear do you reach 60 mph? 2nd gear, 3rd? 60 mph seems like the sound barrier to my bike. It does not clearly accelerate with the same torque from 0 to 60 compared to 60 to 80 for instance. Bike is a cb 750k2

Gordon · « **Reply #1 on:** January 21, 2018, 11:28:22 AM »

Depends on how quickly I'm trying to get up to speed. If I'm accelerating to merge onto a 70 mph freeway I might hit 60 in 2nd gear, but if I'm just cruising up to speed I'll be in 4th or 5th by that time.

Don R · « **Reply #2 on:** January 21, 2018, 12:00:15 PM »

Another way to ask might be what is your rpm at 60.

They do like rpm, while accelerating I'm not fond of over revving a 40-50 year old bike but they don't have a lot of torque at low rpm's either.

aminemed · « **Reply #3 on:** January 21, 2018, 12:06:16 PM »

What do you mean by over revving ?

TwoTired · « **Reply #4 on:** January 21, 2018, 12:15:36 PM »

Quote from: aminemed on January 21, 2018, 12:06:16 PM

What do you mean by over revving ?

Operating in the red zone of the tachometer. Anything below that is perfectly normal and not harmful.

Have you noticed rise of tach needle without a corresponding rise of speedometer needle? Like the clutch is slipping?

If not, do a plug chop when you hit your perceived "acceleration wall", and see what the plug deposits tell you (us).

Cheers,

BobbyR · « **Reply #5 on:** January 21, 2018, 12:33:03 PM »

I tend to merge onto the highway in 3rd gear at bringing it up to 70. At that point I just go right into 5th. These bikes have very little below 4K RPM and really start cooking between 5-7K Rpm. You can really feel it come on.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #6 on:** January 21, 2018, 12:40:49 PM »

spotty · « **Reply #7 on:** January 21, 2018, 02:14:42 PM »

in 1st, but that's on the Vmax so its not entirely relevant, i'm just bragging

aminemed · « **Reply #8 on:** January 21, 2018, 02:38:11 PM »

According to the manual 60 mph should be reached in 2nd gear at 7500 rpm that leaves 1500 rpm before red zone to go beyond 60 mph still in 2nd gear. I guess that a bike need to be properly tuned to match these specs

tlbranth · « **Reply #9 on:** January 21, 2018, 05:57:58 PM »

lowriderbud · « **Reply #10 on:** January 21, 2018, 06:50:49 PM »

I cruise at 60 MPH in 5th gear at 4400 RPM - this is on a '78 750 F SuperSport with stock gearing. I can hit 60 in just about all the gears but 1st. After all, this is a 40 year old bike.

Later, Bud...

Stev-o · « **Reply #11 on:** January 21, 2018, 07:33:56 PM »

I wish I had a 350F, then I could hit 85 in 2nd, like JWilde...

Keith · « **Reply #12 on:** January 21, 2018, 07:48:02 PM »

Your K2 should easily reach redline in the first three gears, and should reach redline in fourth with enough distance. At that point, About 115 mph. Fifth gear? Maybe on a long downhill

RAFster122s · « **Reply #13 on:** January 21, 2018, 11:53:44 PM »

Given about 12 seconds dropped down a mine's vertical ventilation shaft I will reach about 122 mph in any gear you want!

122 mph being terminal velocity and 12 seconds typically about how long it takes to reach that speed. You will need at least 1500 feet of free fall for this, else you are not going to reach terminal velocity.

aminemed · « **Reply #14 on:** January 22, 2018, 12:58:08 AM »

12 sec from 0 to 122 or from 60 to 122 ?

RAFster122s · « **Reply #15 on:** January 22, 2018, 01:21:08 AM »

12 seconds starting from zero, dropped in vertical free fall assuming nothing but normal wind resistance/air resistance you will achieve terminal velocity of roughly 122mph. You will have covered 1500 feet in that 12 seconds.

aminemed · « **Reply #16 on:** January 22, 2018, 02:42:25 AM »

Are you sure ? Yamaha R6 is doing the 0 - 120 mph in 12.2 sec, i doubt that the CB 750 is as fast..

FuZZie · « **Reply #17 on:** January 22, 2018, 04:28:11 AM »

Quote from: RAF122S on January 22, 2018, 01:21:08 AM

12 seconds starting from zero, dropped in vertical free fall assuming nothing but normal wind resistance/air resistance you will achieve terminal velocity of roughly 122mph. You will have covered 1500 feet in that 12 seconds.

I think the Yamaha R6 would do exactly the same.

Yamahawk · « **Reply #18 on:** January 22, 2018, 05:22:09 AM »

Quote from: aminemed on January 21, 2018, 11:07:27 AM

Trying to figure out if my bike settings are good, can you let me know in which gear do you reach 60 mph? 2nd gear, 3rd? 60 mph seems like the sound barrier to my bike. It does not clearly accelerate with the same torque from 0 to 60 compared to 60 to 80 for instance. Bike is a cb 750k2

You will find that acceleration is on a curve, and that the higher speeds are not accomplished in the same time period as the lower speeds due to several factors, one being wind resistance. Another is the torque of the engine to the wheels at lower gear selection is higher, the torque multiplication factor being naturally more due to the lower gear ratios. When you get into the upper gear selections, your rate of acceleration will diminish due to these factors.
Acceleration from 0-60 can be accomplished in 4 seconds, for example.. now this is just an example... acceleration from 60-120 (the next 60 mph) is quite a bit slower, and would be in the 9 second range... again, just an example, due to the other factors mentioned.
Hope this makes it more understandable, if I understand your original question.
And, the terminal velocity of a falling object is due to mean 'ol Mr. Gravity lol....
Charlie

Dunk · « **Reply #19 on:** January 22, 2018, 08:11:47 AM »

Quote from: Stev-o on January 21, 2018, 07:33:56 PM

I wish I had a 350F, then I could hit 85 in 2nd, like JWilde...

Beat me to it!

Seriously though, I'd guess 3rd normally? 2nd maybe if really hauling the mail or 4th if leisurely cruising? If your 750 has trouble getting over 60 you need to look at possible clutch slip as mentioned, as well as air restrictions, fuel restrictions, dirty carbs, etc. Also check that your timing advancer is returning to initial timing and advancing to full advance. They can stick, and if not advancing it will really hurt power. A 750 shouldn't really slow down in the acceleration department until well past 60 MPH.

Yamahawk · « **Reply #20 on:** January 22, 2018, 08:28:56 AM »

...and actually, acceleration from 60-80 in a top gear roll on would be around 10 seconds too. Now, if your K2 won't accelerate past 60mph AT ALL you have a more serious problem...

Charlie

MoMo · « **Reply #21 on:** January 22, 2018, 08:44:29 AM »

Quote from: Dunk on January 22, 2018, 08:11:47 AM

Quote from: Stev-o on January 21, 2018, 07:33:56 PM
I wish I had a 350F, then I could hit 85 in 2nd, like JWilde...

Beat me to it!

Seriously though, I'd guess 3rd normally? 2nd maybe if really hauling the mail or 4th if leisurely cruising? If your 750 has trouble getting over 60 you need to look at possible clutch slip as mentioned, as well as air restrictions, fuel restrictions, dirty carbs, etc. Also check that your timing advancer is returning to initial timing and advancing to full advance. They can stick, and if not advancing it will really hurt power. A 750 shouldn't really slow down in the acceleration department until well past 60 MPH.

Beat me too, although like the WildeOne, I hit 85 in second with my Seca 400. Fact verified my Granny

sdefoor · « **Reply #22 on:** January 22, 2018, 10:05:57 AM »

well if we're just all going to start bragging about 1st gear I 103 in 1st on my R1 lol

Yamahawk · « **Reply #23 on:** January 22, 2018, 11:36:15 AM »

....as Walter Brennan said in "The Guns of Will Sonnett", ...
"NOooo brag, just Fact..."
Charlie

Shtonecb500 · « **Reply #24 on:** January 22, 2018, 08:18:19 PM »

on my 500 I'm getting into second gear after 30mph, shifting into third at 50mph.

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Author Topic: In which gear do you reach 60 mph? (Read 5282 times)