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)

"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.)

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.

"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

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

"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.

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.

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.

"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

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

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

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 (: