Topic: 550K3 top speed

[Tim2005]

550K3 owners.. what's your top speed? I was reading an old Bike magazine (UK mag)  that tested it against a GS550, the report has the 550K3s top speed (rider prone) as 113.21 mph actual,  with the speedo optimistic by 8%, so that's an indicated top end over 120. These figures seem rather higher than my 550 ever felt capable of...

[phil71]

that seems super optimistic. On the bright side, how often do you need sustained speeds over 100mph?

[davidtime]

I thought I read it was 80 something.

[Old Scrambler]

Every time I get west of the Mississippi I see sustained high-speed as a necessity.

A well tuned 550 is capable of about 110 if your under 165 lbs. and glued to the tank.  Sustained speed in the 90s is OK if you pack light and want to stop more often for fuel.

[Tews19]

Plus 1 for Old Scrambler. I think the top speed on my 550F was 95.  But speedo error who knows. One thing cool bout these old bikes is 80 feels like 100! On a modern bike 80 feels like 50.

[davidtime]

102 From Wikipedia, the free encyclopedia haha

[LesterPiglet]

I had 115 regularly on the clock. Clocks lie!

Oh sorry mines an F. That's another 10mph straight away.

[Muckinfuss]

Peak torque is at 8500 rpm...anything above that is just burning gas for the hell of it (rapidly I might add).  Especially as we get older (heavier!  I haven't seen 165lbs since 1979)

[Duanob]

If you increase the size of your front tire your speedo won't read accurately anymore. I think mine is easily 5MPH off at 70. If I'm doing 70 with traffic my speedo is bouncing between 75 - 80.

My front tire is 100/90-19 instead of the stock size. I think it looks better and handles better than stock.

[mono]

If you increase the size of your front tire your speedo won't read accurately anymore. I think mine is easily 5MPH off at 70. If I'm doing 70 with traffic my speedo is bouncing between 75 - 80.

My front tire is 100/90-19 instead of the stock size. I think it looks better and handles better than stock.

well, that answers why i'm always missing traffic lights that i have timed perfectly in my cage.  hooray!  now i can go faster without worrying about tickets.

[strynboen]

mine k3 1978 runs  easy 170...kmt..but spedo shoves 10 +..so 160 kmt..is it 100 miles..think it can run175 kmt om longer roads

[Lostboy Steve]

I've personally had mine to 80+ on the interstate at about 8k. My buddy on a new gsxr was clocking it and apparently my faded speedo is damn near perfect for accuracy. I don't know how much faster I can go at this moment because my rim has a slight dimple on it that I missed so it gets a vibration after 70. I could see 100-110 screaming.

[hymodyne]

With a Mike Rieck mild head port/polish, velocity stacks, 4-1 header, 110 jets, and a 650 camshaft, I can get up to and maintian 100-105 without maxing out rpms.

james

[crazypj]

I thought I read it was 80 something.

 That's the cruising speed but, as mentioned. it uses a LOT more gas
You pretty much have to red line it through the gears to get max speed before running out of road
 Larger front tyre makes speedo run slow, may actually make it more accurate?
My F1 was a bit modified and would easily cruise at 110mph with around 130 top speed but never read more than 120 with 4.10x19 tyre (usually K81 TT100)

[totty]

Mine will reach an indicated 100mph with relative ease sat up right, above that it feels a bit stressed and I've never held it pinned to see what it'll reach. I suspect that if laid on the tank it might reach the the reported 113mph.

I agree with the feeling of speed, 50mph on it feels like 130 did on my VFR, that's one of the reasons I sold the VFR.

[crazypj]

I agree with the feeling of speed, 50mph on it feels like 130 did on my VFR, that's one of the reasons I sold the VFR.

 ................and why I ride a CB360 most of the time, although even that will do almost 120 (it's a bit modified)

[Bailgang]

I agree with the feeling of speed, 50mph on it feels like 130 did on my VFR, that's one of the reasons I sold the VFR.

My youngest used to have a 1st gen VF500F and the way it's wind screen was designed it basically directed the air straight to your helmet and you'd have to lay on the tank to avoid it. My kid remembered that when he got his CBR and promptly replaced it's wind screen with an aftermarket one called a double bubble design I think it's called which directs the air farther away from your helmet.

[bwaller]

The 550 I built to 592 with a Web street cam, tight squish, and mild porting, tuned on a dyno, ran 115mph. This on a straight stretch of quiet road followed by my son checking speed in his WRX.  I have a hard time understanding a stock 550 running more than 100 but good on you if they do, at least the speedo does!

[johno]

mmmmmmmm lookin back at the good ol days

Myself and two mates were having the great debate about top speed and went out the road with a Torana XU1    behind to check the speed.
I was two up on my stock cb 750, mate had a stock cb 500 ( we both used for proddy racin)
and another mate had a BMW 600   spread side by side all of us peaked and held at 110 mph 

Bwaller takes a lot to get a bit hey !    funny thing you mentioned your speed at 115mph .... I ended up doing very similiar engine mods and few frame mods on my mates 500, guess what , same speed as yours ............at best, slight head wind or uphill etc and bam no torque, no guts slowed like a dog.

Ah grasshopper ......upset me at the time.

Just for interest boys any other 500 guys with modified engines with hp and top speed numbers ?
johno

[Romhog]

I have 75' 550F  and I feel like it's a good day when I can hit about 95mph. After 88mph I start hearing Doc Brown yelling  ...and time travel starts to feel possible. 

[Lostboy Steve]

I thought I read it was 80 something.

 That's the cruising speed but, as mentioned. it uses a LOT more gas
You pretty much have to red line it through the gears to get max speed before running out of road
 Larger front tyre makes speedo run slow, may actually make it more accurate?
My F1 was a bit modified and would easily cruise at 110mph with around 130 top speed but never read more than 120 with 4.10x19 tyre (usually K81 TT100)

This might explain why mine is dead on.

[Lostboy Steve]

The 550 I built to 592 with a Web street cam, tight squish, and mild porting, tuned on a dyno, ran 115mph. This on a straight stretch of quiet road followed by my son checking speed in his WRX.  I have a hard time understanding a stock 550 running more than 100 but good on you if they do, at least the speedo does!

Well, Going back to my highly modified moped days, speed isn't going to change unless gearing is changed or rev limit is raised. Your bike probably would blow the doors off of a mildly ported and tunes stock 550, but on the salt flats they are still going to pretty much top out the same. I learned all of this early on when my puch maxi would wheelie down the street but still only do about 35 tops. So after some sprocket changes acceleration stayed about stock (no more wheelies) but I could grab 70mph.

[Lostboy Steve]

I have 75' 550F  and I feel like it's a good day when I can hit about 95mph. After 88mph I start hearing Doc Brown yelling  ...and time travel starts to feel possible. 

My thoughts exactly!

[crazypj]

I do know a Wack-a-zaki 350 triple would blow the doors off it and CB550 top speed was about 105-110 MPH under ideal conditions with mine when new.

rt

 only to about 85~90mph, then they run out of puff
On a decent trip (50+ miles, 350 or 400 kwac would drop way behind (looking for a gas station)
1977 CB550F1 was road tested at 112mph, with 12.76 standing quarter forget which mag though