Topic: breaking 100 mph

[HondaMan]

Speed limit in western Wyoming is 85 MPH, and riding at that speed can get you run over in the summer...from behind.
But, Colorado's roads are the worst in the American West, in sharp contrast just one State away. Here, they don't think a 100-foot long, 8"-wide, 6" deep gap in the pavement is anything to worry about repairing (there are many of these around here, been there for years now), but it will take you down if you don't know it is there(!).

This said: I only rode 100+ twice on My 750K1, because it was too hard to hang on sitting up, and [in those days] I could not lay down on the tank and solidly hold the bars at the same time. The Vetter totally changed that: 100 was a happy afternoon's ride on my K2 when I knew no gendarmes lurked. Now that it makes more power than it used to, I have hit the ton a number of times by accident during on-ramp events in suburban traffic around here, to avoid being run over - from behind. This was one of the primary reasons I rebuild my trusty steed in 2013, as I got caught off-guard several times in 2012 by a##holes from behind me ripping around me (much too close) in things like Subaru WRXes or HiPo Mustangs, deciding they wanted to rip around me on these on ramps. Both nearly ran me off the road as I was casually reaching 80 MPH to merge, so it became time to change my MO.

The 750K1-K6 has a tendency to speed wobble when slowing down if your chain and sprockets are not in tip-top condition and the swingarm and steering head (and wheel axles) have solid, tight bearings in them. Actually, this is true of many bikes, but I know this one best...so, make it tip-top and then it will be without surprises.

I don't recommend it, though, unless you AND your bike are well practiced at it and certainly not where wildlife or Statees abound. Both can become painful & expensive! And, it requires familiarity with the pavement, above all, before you attempt it, ESPECIALLY if you live in Colorado...

[MauiK3]

 Back in the day, shortly after I got my K0 750 new, I took my mom for a ride on a little used road in the Jacksonville Florida area. My mom was a pretty game redhead that liked a little fun. I took it up to an indicated 115 albeit leisurely. She loved it. My dad wasn’t pleased.
I had that bike to an indicated 125 which I’m sure wasn’t 125 but it was fun. I would no more do that now than fly. Somehow I just don’t want to risk messing the bike or myself up even though I know the bike could do it. I may blip it up someday with my wife on the back just for the experience but there aren’t many places to do that here on Maui.

[evinrude7]

Have you done 100 mph yet?

Back in early 80's when my K6 was stock I rather often could not stop at my highway exit late evenings/nights since the cooler air was really good for better power which I felt, bike wanted to run! Speedo slowly closing 190kmh.

Today, +30kg rider more but compensated with more cc, bike accelerate very stable passing 190kmh it can hold with ease. No wobble or other issues. It's more about the focus on the road, bumps, animals and other people on the road that make me to reduce.

Curves are thrown into my face way too quick in that speed too!

I can not see any use of a modern bike making 250-300kmh on a normal road.

Most fun on a SOHC CB750 is between 70-150kmh with occasional accelerations to 190kmh for a km or 2

Actually not yet Per. Found curves to be more fun than straightaways. I guess I'm in my fourth year might be fifth of regular riding now. Have hit low 90s on the freeway once in a while.

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[Doobie]

The problems of high-speed motorcycling... 1975 vid explains "weave" and "wobble" (bonus: CB750F at 4:20-ish)

[MauiK3]

Very good video
I've never had much trouble with high speed wobble and I'm 5' 6" and have weighed about 145 lbs for many years. I wonder why. I've been up at high speeds.
The video makes it seem a certainty that this will happen but I'm not sure it's as certain as they say, how about others here? Does it always happen to you?

[evinrude7]

Haven't had it yet Maui. 5'10" 175.

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[PeWe]

The steering damper kit sold back in the days helps to get it stable, especially when having luggage and passenger. Yamiya had that in stock not long ago, probably today too.

On Autobahn I held +100 mph most of the time with passenger and luggage. 836cc and probably closer to 80whp.
 
No wobble at all. From north to south Germany around 1200km. + thru Austria, Italy or Spain another year.

 Same distance back.  French highways even easier to ride fast. I had to stop more frequent to refuel when riding 160-180, sometimes more
I remember a slightly downhill from Austria to Italy when I had to pass a Jaguar XJS.
Speedo showed 210kmh, long nice curve and I start to think if I really tightened the nuts holding the front wheel good enough. that was really max. The driver in that XJS looked worried since we were side by side for a while.

 This with 2 guys and lots of luggage. The frame had nice swinging, bending without wobble.

Not much to brake with....

Tapered roller bearings at front, needle bearings in swingarm and good shocks have been parts of the stability, not only the steering damper which was a must have.

So 100mph is nothing for a stock CB750. I had tried 110mph on my stock K2 just to try the jets last year.

[72 yellow]

Track day only.  I did the ton once back in the 70's on a freeway in Detroit.  Ran through a state police radar trap.  The thought of me in jail and the bike hanging by a chain at the back of a wrecker kept me going.  I got off and on to the service drive and watched him speed by.  Never again.

[my name is nobody]

I always remember that, no matter fast/good you are, someday, for whatever reason, you WILL go down. It's as
certain as dying.  And the highsiders hurt more. ..Don't let speed mesmerize you too much.

[bryanj]

1971 on a 1959 Triumph T110 indicated 110mph middle of day on a UK dual carriageway(has a median divider) scared #$%*less when tried to stop with 7 inch sls drum front brake!!

[Alaxy Galaxy]

Around 2005-2006 I took my 400/4 up to an indicated 110mph. It was probably a bit slower, but it was quick enough for me. I can't bring myself to go much faster than 85mph with this one (got 2 kids now), but the bike wants to go faster. I might bring it to a track day just to see what it can do.

I've never experienced any wobble either, but I'm not a big man (5'4", 120lbs).

[grcamna2]

That's an interesting video.
I'll remember to keep my tire pressures checked,front fender/fork brace tight,front forks maintained and steering bearings properly snug.I would like to see a video of the 'string method' way of checking front/rear wheel alignment.
I think the choice of tires/sizes should be carefully chosen plus wheel alignment.Have any of you been challenged by certain road surfaces/rain grooves?

[andy750]

On Autobahn I held +100 mph most of the time with passenger and luggage. 836cc and probably closer to 80whp.
 
No wobble at all. From north to south Germany around 1200km. + thru Austria, Italy or Spain another year.

 

+1. I have been fortunate to ride both in the US and in German autobahns on the same CB750K2 (stock). On the autobahn rode at 100+mph for hours as we went from the Netherlands to Munich. At that speed (~110mph) we were getting passed easily by all the cars . Bike never had a wobble or any handling issues and stopping wasnt an issue as few exits and most importantly Germans know what lane to be in so no one sits in the outside 2 lanes. Both my CB750 K4 and K2 have been above 100 mph (GPS-recorded) with no issues.

[evinrude7]

That's an interesting video.
I'll remember to keep my tire pressures checked,front fender/fork brace tight,front forks maintained and steering bearings properly snug.I would like to see a video of the 'string method' way of checking front/rear wheel alignment.
I think the choice of tires/sizes should be carefully chosen plus wheel alignment.Have any of you been challenged by certain road surfaces/rain grooves?

sometime between last fall and early spring i posted about an oddity i felt in the front end.  stopped and yanked on the front end and nothing seemed out of place.  i believe it was deemed a longitudinal pavement seam in the road that i went back and found.  we have a freeway here in nashville that had grooved concrete on much of it a few years back.  you feel a little squirrely on it but it doesn't result in disaster. 

[seanbarney41]

that groovey pavement squirm is largely dependent upon front tire design...ribbed type tread such as Avon Speedmaster, Dunlop K100?, and those vintage Continentals that everyone seems to otherwise love, and it seems like you are gonna die!  More modern tread design and its fine...

[Doobie]

+1. I have been fortunate to ride both in the US and in German autobahns on the same CB750K2 (stock). On the autobahn rode at 100+mph for hours as we went from the Netherlands to Munich. At that speed (~110mph) we were getting passed easily by all the cars.

I will never forget doing 100+ mph on a Triumph Bonneville on a trip from Paris to Stuttgart and getting blown off the autobahn by Porsche 911s like it was nothing. Although I lived in Germany for many years off and on, it was the only time I was on the autobahn on a motorcycle (the Triumph wasn't mine sadly).


I've taken my K6 up to 100 mph. There was still plenty more in it but after 90 mph these old bikes get too hairy for me. I just put my CB750F on the road and I'll probably take it up to 100 once or twice to see what it feels like but that will be it.

[Redline it]

i was driving, well roading a GI water truck across town, one morning, near a busy high school (the one i went to,) i was about 18, the last thing the superintendent said to me was to go slow and take it easy. he didn't tell me why. after about 8 miles and i could see the job, i was going just slightly downhill, not steep. these things didn't have seat belts. there was about a half tank of water, truck was about 4000 or 6000 gal. and there's traffic going the opposite way 50+ mph. i'm going about 15 or 20mph. all of a sudden the steering wheel started going from lock to lock, hitting the brakes only stopped it before the next high speed wobble shockwave would knock me back off in the other direction. felt like the cab was falling off. dirt and dust filled the cab, the truck was all over the road barely missing head on cars.  the superintendent would of made a excellent member on this forum site. he didn't have much to say in terms of details. i walked a dozer kamatsu d-65e  the size of d7 caterpillar, not real big, straight off an inverted vertical rock face, onto to light loads of dry topsoil, that i just pushed off, on solid rock. the truck was probably 2nd to that. other than water all over the truck and highway nothing happened to it, the dozer was totaled. landed on its top square and sprung itself back over onto its tracks, i wasn't wearing the seatbelt. good times.