Topic: Is A '71 CB500 highway safe

[projectile]

Hey guys,
I have heard some rumors about the safety of the early honda motor cycles.
1) they are not stable at high speeds on the highway and should not be driven above 50mph
2) if you hit Rail Road tracks at a certain angle on an early Honda the bike will just fall over

Is this true?

Thanks,
Jonathan

[Harry]

Nope.

Poor tyres/ old tyres will make your Honda (and all othe bikes) do these things though.

[Einyodeler]

 
Let me guess,you heard these rumors from HD riders ,huh? My `72 CB500 takes me to work into the city every day 100+ miles roundtrip and around here if you`re not doin` 75 - 80 mph then you`re gonna get run over.Slash that rumor.And I always try to cross the RR tracks at a crossing,haven`t fallen over yet.Now if I were to stop on the tracks and forget to put my feet down,yeah then I could see it happening.Slash that rumor too.

[Chrisboden]

The suitability of a given bike for highway travel is dependent on the particular bike. First off, not all models are even legal (much less safe) for highway use. In Michigan the bike has to be over a certain displacement (I think it's 125 or 250cc) and maintain a certain minimum speed (45 or more Mph). But regardless of that, you can line up a dozen 75-cb550-k's and half of them may be safe, half of them may not. It depends on the particular condition of the bike itself, and your ability as a driver.

As far as tracks, standard railroad tracks are about 6" tall and are 4' 8 1/2" between centers, if you can hit those at any speed and not fall over you're a better driver then I am.

So let's assume you meant at a crossing, shall we?

Now, railroad cars and locomotives may ride on top of the rail, but their steering control is done by a flange on the inner wheel rim that rubs the inside of the rail heads. Because this flange extends below the top of the railhead there has to be a grove for it to ride in where tracks cross over a street.

And that's your problem.

When you cross a set of tracks at 90-degrees (a right angle, or perpendicular to the direction of the tracks) you're fine. But not all crossings are at 90*. If it's a more acute angle, then you have to make a little swerve across the road to cross over the tracks at a right angle. If your crossing angle is to acute, you can easily catch your front tire in the flange groove and lose control of the bike. The result would most likely be the front of the bike pulling sharply to one side, laying you down, but in a worst case scenario you may wedge the wheel into the flangeway and the bike comes to a sudden and fierce stop.

Of course....hitting a train would ruin your whole weekend as well. In a Honda-Vs-Anything fight Honda almost always loses, and in Honda-Vs-GP40 it would be particularly bad.

Chris "Motorcyclist Ferroequinologist" Boden

[Bob Wessner]

Ferroequinologist, ha. I just had to go look that one up. 

[Chrisboden]

And there's your nickel word for the day

Could apply to motorcycles in a way too

For those that don't look it up, Ferro=Iron, Equine=Horse, Ologist=One who studies. It's usually used in the context of Trains.

[Warlock]

Greets,
I have been riding my '71 CB500k for over 30 years at highway speeds without incident. When I purchased the bike in '71, the national highway speed limit was still 70mph. Needless to say, the 500 was able to cruise at that speed (and beyond, at times)  with no problems. Insofar as the RR track issue, I have crossed tracks at oblique and acute angles over the years without incident. Although at the time, it was considered safe riding procedure for all riders to cross tracks at right angles. This was to avoid the possibility of a narrow profile tire (common at the time) from falling into and following the space between the rail and the road surface. This would ,in effect, cause the forks to violently skew at speed and cause loss of control. Present day RR crossings have much narrower gaps between the rail and road surfaces and are not as problematic. That being said, the fact I am still alive today, with all body parts intact, should be proof enough....

[dusterdude]

yea,but you`re a warlock,i dont think you`re ever supposed to die.

[Harry]

As far as tracks, standard railroad tracks are about 6" tall and are 4' 8 1/2" between centers, if you can hit those at any speed and not fall over you're a better driver then I am.

Chris "Motorcyclist Ferroequinologist" Boden

Ferroequinologist, eh? Oooooh! Then as you know, the rather strange 4 feet 8 ½ inches gauge is used because it's the way railway lines were built in Britain and it became the standard in many parts of the world during the time of the British Empire and were laid by British engineers. The British built them like that because the first railway lines were constructed by the same people who built the pre-railway tramways, and that was the gauge trams used. Why did trams use that obscure gauge then? Because the people who built the tramways used the same jigs and tools that were used for building wagons, which used that wheel spacing. And why did the wagons have that particular odd wheel spacing? Because if they tried to use any other spacing, the wagon wheels would have broken on the old long distance roads in England - because that was the distance between the ruts in the roads.

So who built those old rutted roads? Imperial Rome built the first long distance roads in Europe (and England) for their legions and the roads have been used ever since. And where did the ruts in the roads come from? Roman war chariots formed them initially and then everyone else had to follow suit for fear of destroying their wagon wheels. Since the chariots were made for (or by) Imperial Rome, they all had the same wheel spacing.

And so the international standard railway gauge of 4 feet 8 ½ inches comes from the specification for an Imperial Roman war chariot, which were made just wide enough to accommodate the back ends of two war-horses.

And this is why all motorcycles excepting Italian motorcycles should be driven with caution over railway crossings.

[Warlock]

Not true...I was a hockey puck in a previous life.....

[dusterdude]

i aint touching that

[Geeto67]

Here are a couple of issues not yet mentioned in considering whether a bike is "highway safe"

1) rider weight: if you are average weight/average height this really isn't a consideration but if you are say 300lbs there are a lot of small displacement 70's bikes that wouldn't be highway safe under your fat arse (yes I speak from expirence). My personal standard is this: if the bike is safe to ride at 70-80 mph and can actually carry you to that speed in real life for a sustained period of 1/2 an hour then it is highway safe.

2) brakes: In the 70's automobile brakes sucked, and comparativley speaking motorcycle brakes were good. Fast forward to today. Car brakes are awsome and getting better all the time, and new bike brakes can actually flip you forward. But 70's bike brakes have not evolved an inch. MY girlfriend's old broken down 1993 toyota corolla can out stop my well maintained 1975 honda cb750. Most riders forget this when they get on the highway with their bike and follow behind the car in front as if they were in a modern cage. Personally I use a 10 car lengths as a measure and I try not to ride in the left lane under 80 mph to keep the 90+ mph drivers from cutting me off at speed. Just because the bike is highway safe doesn't mean you are.

The myth about hondas being unsafe at hight speeds and across railroad tracks comes from , at least I have always been told, the weight of small displacement hondas in comparison to other heavier bikes. Nowadays modern roads have improved, and modern sportbkes are 10x lighter than these old hondas but back then it was believed that at high speed a large bump could upset these bikes and that the bike was too light to cross railroad tracks at speed because the tire would hit against the rail, upset the bike and you would dump. These are myths but there is some truth to them, stupid riding on bad roads, riding on new tires with abandon, or anyother million no-nos will cause you to take a slide.

[TwoTired]

Johnathan,
The 71 CB500 is very nearly the same bike as my 74 CB550. I've been riding it since 1975.  I can think of no part of the machine's design that makes it inherently unsafe.  If the bike is kept somewhere near the condition it was when sold, highway safety is determined by the operator or, perhaps, its mechanic.

I wonder of the origins of your rumors.  Could they have been originated by those who had something to gain by forming an opinion in you?  If such statements (the rumors you've heard) were made to me, I would question that person's credibility.  But, then I question sooo many things...

But, now a question for you.  Did you really think people on a site dedicated to preserving and sustaining these machines is going to tell you they aren't safe?

Cheers,

[projectile]

Hey Guys,
Thanks for all the replies and information on railroad history.
The rumors where from the guy who sold my boss his CB500 and hearsay from a Holographer. I have no reason to think my bike would be unsafe on the highway, I just wanted to check before I tried it.
Thanks,
Jonathan

[cben750f0]

mate just get out there and enjoy your SOHC 4...

 harry, i put a thing in the humor forum, about the exact same thing... of why the railways are like they are...  .. glad someone found a use for it!!! ..peace

[Zeke]

Nope.

Poor tyres/ old tyres will make your Honda (and all othe bikes) do these things though.

I'm suprised how many old hondas are for sale with 30 year old tires.  The guy I bought my bike from insisted that the tires were "fine" and had "good tread".

I rode the bike home with those tires and immediately took them off and replaced them with some semi-sticky new Dunlops.

Definately don't trust your life to old tires -- the result might be more than just a flat tire.

BTW, I ride my 650 100 miles a day at 65-85 mph -- the feel is fine.

out

Zeke

[oldbiker]

Any bike can be as safe as the loose nut behind the handlebars.