Honda 6 cylinder 250cc bike from 1966
 

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda


--
Steve Walker
(remove wallet to reply)

Honda 6 cylinder 250cc bike from 1966
 

"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda


I remember reading an article about that engine.

Valve adjustment:

a) disassemble engine
b) put plastiguage on top of pistons.
c) assemble engine
d) crank engine over once
e) disassemble engine
f) measure plastiguage
g) grind end of valve stem to suit f)
h) assemble engine

(No rockers, cam drove the valve stems directly.)

Honda 6 cylinder 250cc bike from 1966
 

jtaylor wrote:
"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda



I remember reading an article about that engine.

(No rockers, cam drove the valve stems directly.)

You can't get any less valve train mass than that. It must of had a very
high rev limit before the valves started to float.

Honda 6 cylinder 250cc bike from 1966
 

"tomcas" wrote in message
...
jtaylor wrote:
"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda



I remember reading an article about that engine.

(No rockers, cam drove the valve stems directly.)

You can't get any less valve train mass than that. It must of had a very
high rev limit before the valves started to float.


The RPM's were probably high for that era, but have you ever checked the red
line on a '06 Yamaha R6? Max HP is at 14,500 RPM! Red line is 17,500 RPM.
This out of a production bike, with a warranty!
Greg

--
PoorUB
'05 Ultra Classic

Honda 6 cylinder 250cc bike from 1966
 

tomcas wrote:

jtaylor wrote:
"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda



I remember reading an article about that engine.

(No rockers, cam drove the valve stems directly.)

You can't get any less valve train mass than that. It must of had a very
high rev limit before the valves started to float.

16,500 rpm

Tom

Honda 6 cylinder 250cc bike from 1966
 

"tomcas" wrote in message
...
jtaylor wrote:
"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda



I remember reading an article about that engine.

(No rockers, cam drove the valve stems directly.)

You can't get any less valve train mass than that. It must of had a very
high rev limit before the valves started to float.

I seem to recall that Honda had a watercooled 4-valve 50cc triple in
development that revved to _well_ over 20K. This was to replace the 22.5K
rpm twin that made 320 bhp/litre. See:

http://www.vf750fd.com/Joep_Kortekaas/1966.html

for some nice pics, including a completely disassembled 250 six motor, all
neatly laid out.

Honda 6 cylinder 250cc bike from 1966
 

Sounds like a 2 stroke to me, especially with the revs to
keep it alive. Needs a bit of tuning. I'd have to see a
phote of a head to believe it's a 4 stroke.

Bart D. Hull

Tempe, Arizona

Check http://www.inficad.com/~bdhull/engine.html
for my Subaru Engine Conversion
Check http://www.inficad.com/~bdhull/fuselage.html
for Tango II I'm building.

Remove -nospam to reply via email.

tomcas wrote:
jtaylor wrote:

"Steve Walker" wrote in message
news:4fFxf.24909$em5.17566@trnddc05...

Awhile back there was a discussion about a 4 cylinder 250. Here's a link
to video of a 6 cylinder 250cc Honda.

http://video.google.com/videoplay?do...091875&q=honda



I remember reading an article about that engine.


(No rockers, cam drove the valve stems directly.)

You can't get any less valve train mass than that. It must of had a very
high rev limit before the valves started to float.

Honda 6 cylinder 250cc bike from 1966
 

Oh, they were 4 strokes, and built much like a bike that I have now. I
don't think that the HP per liter of these engines has been surpassed
to this day, by 2 or 4 strokes. correct me if I am wrong.

Honda 6 cylinder 250cc bike from 1966
 

"Bart D. Hull" wrote:

Sounds like a 2 stroke to me, especially with the revs to
keep it alive. Needs a bit of tuning. I'd have to see a
phote of a head to believe it's a 4 stroke.

Bart D. Hull

Tempe, Arizona

If you're referring to the Honda six, it was definately a four stroke.
Tuned to run at pretty much unheard of revs for it's time, it did not
idle so well, apparently. That and the fact that it was running six
megaphone exhaust pipes, effectively tuned to help produce high rpm
power.

I had a back issue of the Brit bike mag, Classic Bike, in which they
had a teardown and some test reports on that one.

It was right about the era of these bikes, IIRC what I read, that the
FIM set in place a bunch of rules limiting the numbers of cylinders for
given displacements (or perhaps it was limiting the numbers of gear sets
in the transmission), effectivly ending that particular evolutionary
(revolutionary?:-) )path.

http://www.eurospares.com/graphic2.htm Has a couple shots of one of
these Hondas that has been put back on the track by an outfit called
Team Obsolete. They have some cool toys!

Cheers
Trevor Jones

Honda 6 cylinder 250cc bike from 1966
 

In article ,
"Bart D. Hull" wrote:

Sounds like a 2 stroke to me, especially with the revs to
keep it alive. Needs a bit of tuning. I'd have to see a
phote of a head to believe it's a 4 stroke.


Here you go, Bart. Find the valvetrain.

http://www.vf750fd.com/Joep_Kortekaa...ry/rc166-2.jpg

--
Ted Bennett

Honda 6 cylinder 250cc bike from 1966
 

Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)

Still no reason for it to run so poorly down low. Lots of
race bikes are "race tuned" (pun intended) so they barely
run, but they sound cool. When they run properly they really
put out hp and torque. My parents used to run a motorcycle
shop since 1976 to about 7 years ago, so I've seen my share
of the aforementioned "race bikes".

Bart D. Hull

Tempe, Arizona

Check http://www.inficad.com/~bdhull/engine.html
for my Subaru Engine Conversion
Check http://www.inficad.com/~bdhull/fuselage.html
for Tango II I'm building.

Remove -nospam to reply via email.

Ted Bennett wrote:
In article ,
"Bart D. Hull" wrote:


Sounds like a 2 stroke to me, especially with the revs to
keep it alive. Needs a bit of tuning. I'd have to see a
phote of a head to believe it's a 4 stroke.



Here you go, Bart. Find the valvetrain.

http://www.vf750fd.com/Joep_Kortekaa...ry/rc166-2.jpg

Honda 6 cylinder 250cc bike from 1966
 

"Bart D. Hull" wrote:

Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)

Still no reason for it to run so poorly down low. Lots of
race bikes are "race tuned" (pun intended) so they barely
run, but they sound cool. When they run properly they really
put out hp and torque. My parents used to run a motorcycle
shop since 1976 to about 7 years ago, so I've seen my share
of the aforementioned "race bikes".

Bart D. Hull

Perhaps you need to send your resumé to Honda? Perhaps
they are in need of your "expertise" in the field of
250cc 6 cylinder factory racers?

Tom

Honda 6 cylinder 250cc bike from 1966
 

On Sun, 15 Jan 2006 20:05:07 -0700, "Bart D. Hull"
wrote:

Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)

It's just about the most famous racing motorbike ever made (and most
famous rider). Kids who were my age could draw the engine from memory.
Don't you just _know_ how the valvetrain on this bike worked? Many of my
generation did when they were about 8 years old.

Yet _you_ think "it sounds like a two stroke"

Honda 6 cylinder 250cc bike from 1966
 

"Bart D. Hull" wrote in message
...
Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Honda 6 cylinder 250cc bike from 1966
 

Ted Bennett wrote:

In article ,
"Bart D. Hull" wrote:


Sounds like a 2 stroke to me, especially with the revs to
keep it alive. Needs a bit of tuning. I'd have to see a
phote of a head to believe it's a 4 stroke.



Here you go, Bart. Find the valvetrain.

http://www.vf750fd.com/Joep_Kortekaa...ry/rc166-2.jpg


The lack of any significant flywheel mass
might explain the poor idle (:

Honda 6 cylinder 250cc bike from 1966
 

"Jim Stewart" wrote in message
.. .
Ted Bennett wrote:

In article ,
"Bart D. Hull" wrote:


Sounds like a 2 stroke to me, especially with the revs to keep it alive.
Needs a bit of tuning. I'd have to see a phote of a head to believe it's
a 4 stroke.



Here you go, Bart. Find the valvetrain.

http://www.vf750fd.com/Joep_Kortekaa...ry/rc166-2.jpg


The lack of any significant flywheel mass
might explain the poor idle (:

As would carburetor technology in the '60s.

Peter

Honda 6 cylinder 250cc bike from 1966
 

jtaylor wrote:

"Bart D. Hull" wrote in message
...
Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Honda 6 cylinder 250cc bike from 1966
 

"Tom" wrote in message
...
jtaylor wrote:

"Bart D. Hull" wrote in message
...
Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(some googling ensues)

http://www.cbxclub.com/davespage/250-6.html - no answer, but nice pics

http://www.cmsnl.com/classic-honda-g...dia.php?id=513 - put it on
the yellow, Mike.

Honda 6 cylinder 250cc bike from 1966
 

I wasn't born yet in '66.

I was riding motorcycles when I was 4 or 5, but that was in
1973. If you haven't worked in a motorcycle shop you just
wouldn't understand the irony of most "race bikes."

My current bike is a 1995 Triumph Speed Triple that was
a Speed Triple Challenge race bike. Then it went to a local
Triumph Dealer and "race tuned" to 65 HP for the owners
personal use. (Dynojet dyno tested after I purchased it and
before I fixed it up.) This bike stock is about 87 HP.

With minor tweaks it now puts out 110 hp at the rear wheel.
(Another dyno run.)

Just one example of many that I saw. I truly admire the
professional motorcycle race teams, but despise the B.S.
of the wanna be racers.

It is a shame that most of motorcycle history is not well
documented. I'm sure most of you that "knew how the valve
train worked" were around to witness it in person or see it
in a then current motorcycle magazine. Now some of
the truly odd bikes get written up now and again. (I'm
thinking of the Moto Guzzi V-8 road racer that was a small
displacement motor as well.) Anybody here ever see one of
those in person?

Time for a ride on the Triple, it's 78 degrees and clear
here in Sunny Arizona.

Bart D. Hull

Tempe, Arizona

Check http://www.inficad.com/~bdhull/engine.html
for my Subaru Engine Conversion
Check http://www.inficad.com/~bdhull/fuselage.html
for Tango II I'm building.

Remove -nospam to reply via email.

Andy Dingley wrote:
On Sun, 15 Jan 2006 20:05:07 -0700, "Bart D. Hull"
wrote:


Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


It's just about the most famous racing motorbike ever made (and most
famous rider). Kids who were my age could draw the engine from memory.
Don't you just _know_ how the valvetrain on this bike worked? Many of my
generation did when they were about 8 years old.

Yet _you_ think "it sounds like a two stroke"

Honda 6 cylinder 250cc bike from 1966
 

'05 Ultra Classic
"jtaylor" wrote in message
t.ca...

"Tom" wrote in message
...
jtaylor wrote:

"Bart D. Hull" wrote in message
...
Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(

You could be partly correct. It is very possible that it had bucket style
cam followers without any method of shimming the valve clearance.
Greg

Honda 6 cylinder 250cc bike from 1966
 

Greg O wrote:

'05 Ultra Classic
"jtaylor" wrote in message
t.ca...

"Tom" wrote in message
...
jtaylor wrote:

"Bart D. Hull" wrote in message
...
Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(

You could be partly correct. It is very possible that it had bucket style
cam followers without any method of shimming the valve clearance.
Greg

Actually it had can type followers, hollow but with closed ends.
http://shopswarf.orcon.net.nz/hondavalvegear.jpg
The pic is of the 250cc four that the six was a scaled down version.

As for setting valve clearances by grinding the valve stem ends,
the Ford flathead V8, for the majority of its life had that system
of adjustment as did other Ford engines.

Tom

Honda 6 cylinder 250cc bike from 1966
 

Tom wrote:

Greg O wrote:

'05 Ultra Classic
"jtaylor" wrote in message
net.ca...

"Tom" wrote in message
...

jtaylor wrote:

"Bart D. Hull" wrote in message
t...

Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(

You could be partly correct. It is very possible that it had bucket style
cam followers without any method of shimming the valve clearance.
Greg


Actually it had can type followers, hollow but with closed ends.
http://shopswarf.orcon.net.nz/hondavalvegear.jpg
The pic is of the 250cc four that the six was a scaled down version.

As for setting valve clearances by grinding the valve stem ends,
the Ford flathead V8, for the majority of its life had that system
of adjustment as did other Ford engines.

Not to mention Briggs and Stratton lawnmower
engines.

Honda 6 cylinder 250cc bike from 1966
 

Jim Stewart wrote:

Tom wrote:

Greg O wrote:

'05 Ultra Classic
"jtaylor" wrote in message
net.ca...

"Tom" wrote in message
...

jtaylor wrote:

"Bart D. Hull" wrote in message
t...

Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)


Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(

You could be partly correct. It is very possible that it had bucket style
cam followers without any method of shimming the valve clearance.
Greg


Actually it had can type followers, hollow but with closed ends.
http://shopswarf.orcon.net.nz/hondavalvegear.jpg
The pic is of the 250cc four that the six was a scaled down version.

As for setting valve clearances by grinding the valve stem ends,
the Ford flathead V8, for the majority of its life had that system
of adjustment as did other Ford engines.

Not to mention Briggs and Stratton lawnmower
engines.

Yes, best not to mention.

Honda 6 cylinder 250cc bike from 1966
 

I have been told the old Aston Martin straight 6 had the same system as
well. The guy that told me said it was a major pain to assemble it all,
measure it, disassemble, grind, reassemble , and check again. Maybe one
reason so many were changed for the Jaguar straight 6 which used shims.

Tom wrote:

Greg O wrote:

'05 Ultra Classic
"jtaylor" wrote in message
net.ca...

"Tom" wrote in message
...

jtaylor wrote:

"Bart D. Hull" wrote in message
t...

Interesting,
Even looks like 4 valve heads. Too bad you can't really see
how the valve train was put together. (Shim over bucket,
shim under bucket or shim on valve stem.)

Cam on valve stem, no shim.

Really? Have another look.

Hmm, could be memory and/or eyesight playing tricks.

I do specifically remember reading the bit about grinding the end of the
stem to adjust clearances, but those twelve bits above and below the valve
springs do look like they could have a pair of "buckets" - is that the
technical term...

(

You could be partly correct. It is very possible that it had bucket style
cam followers without any method of shimming the valve clearance.
Greg


Actually it had can type followers, hollow but with closed ends.
http://shopswarf.orcon.net.nz/hondavalvegear.jpg
The pic is of the 250cc four that the six was a scaled down version.

As for setting valve clearances by grinding the valve stem ends,
the Ford flathead V8, for the majority of its life had that system
of adjustment as did other Ford engines.

Tom

Honda 6 cylinder 250cc bike from 1966
 

Bart D. Hull wrote:

It is a shame that most of motorcycle history is not well
documented. I'm sure most of you that "knew how the valve
train worked" were around to witness it in person or see it
in a then current motorcycle magazine. Now some of
the truly odd bikes get written up now and again. (I'm
thinking of the Moto Guzzi V-8 road racer that was a small
displacement motor as well.) Anybody here ever see one of
those in person?


most of it is repeats too, when honda brought out the v4 750 water
cooled as a world first it took about teb seconds for people to point
out ajs did one in 1933, only 500 cubes but it had a blower....

btw, you'll enjoy
http://www.mgcycle.com/V8.html

guzzi v8 sounds / pix etc