valve and guide clarification

[G-Man]

Dick

Great sentiment, and I share your interest in investigating and tweaking things. Yes, I fell in love with these bikes at 14 and enjoy both possibilities of building someting as near to factory spec as possiblke AND building something just for me.

These bikes are very malleable and can be tweaked to your preference. I am thinking about building a miniature Laverda SF as a sort of humorous homage to Laverda copying the CB77 design...

Beautiful work on the Chevy engine.... :-)

I also have a small collection of model plane and boat engines. Anything that burns fuel, makes a noise and smells - I'm there......

G

I see you are building a FULL RACE ENGINE.
As there are many folks watching a series of discussion like this one and I see replacing things which I seldom see needing replacement
I ask WHY so others don't think "I have to do that"when they work on their engines/bikes.
I remove the cam bearings by placing them in the jaw of my vise wide enough for the lobe to clear but the sides of the inside race rests on both jaws. BLAM.
I don't use any other valves other than HONDA as when I rebuild heads I make them HONDA STOCK.
I build engines to be easy starting, run like HONDA intended, able to ride for miles at a time with usually nothing more than points adjustment and cam chain adjustment.
I see in your case you are building for POWER now that you have described ALL the PARTS you are CHANGING.
Are you building a VINTAGE RACE ENGINE?. ...............lm

I don't know that it will be a "full race engine", but some things mfr's do are more cost-effective, much to the chagrin of designers and engineers. No doubt a crank-mounted ignition will be more precise than the stock system, and why I am eliminating a half pound of unnecessary rotating mass. I've generally found a little "tweaking" here and there can improve performance and reliability. Besides, I love internal combustion engines, from my model airplane engine collection , to the big block Chevy in my garage [it's not in anything, but I really had fun building it, and am trying to convince my wife to let me set it in the living room with a glass top as a coffee table].
In my opinion, the 305 engine was one of the most aesthetically beautiful engines Honda ever produced, but Honda's casting and manufacturing capability was not then what it is today - hence a few "tweaks" here and there. As a retired toolmaker, I can't leave well-enough alone, and my Super Hawk is going to look some what like a vintage track bike. I have another that will go back to show room stock.
A couple of pics of my 1961 Chevy 348 [first big block], starting with a "before" pic. I had a '61 Impala SS in '68, with the 3x2 set-up - always liked that engine.

Hello Dick.
I have a couple of questions about the guides and cam bearings.
What was the reason to replace the guides?
The wire Cir Clip is a limiter to stop the depth of the guide to an exact depth as the guide is installed from the top.
I've found "2" bad guides in all the heads I've rebuilt.
Both were intake and both had cracked in halt at the lower groove made to allow air to inter when the valve opens. (not much air and after time HONDA removed that from the guide/head.)
All the actual HONDA valves I have are the same as to magnetism. (I have plenty here and they usually have a "B" cast on the head but not all the exhaust but most do have the "B".
All of the intake is steel which is drawn to the magnet.
All of the exhaust will not draw to the magnet.
Beware of the CHEAP after market valves on eBay.
HONDA shows using a piece of wood and rubber mallet to drive the cams out.
I use Brass or Aluminum rod.
Did the 250 degree heat ruin the neoprene on the advance weights?
Do you think there may be a possibility that the steel dome may come loose if the head is heated several times? (I've had 2 leakers and I hadn't heated either of them.)
. ....................lm

Thanks, lm
I am considering making new valve guides from SAE no. 62 hard bronze - an excellent material for severe use. The ends of my guides are pitted, and I am concerned with carbon build up around the stem.
All of my exhaust valves with a "B" are entirely non-magnetic - is that your preference, lm?
250 degrees is only 38 deg above boiling, hot enough for the aluminum to expand, and less than the operating temps of the head. I put a couple of pennies on the point cam under my vise grip jaws to protect it, and the cam came out with little effort. The same for the opposite cam. The cam bearings are a press fit on the cam, and I have always been hesitant driving bearings out, whereby the races and balls take the shock load.
As for the neoprene on the advancer weights, they do not seem to be affected; besides, I am using the Sasche-Elektronic crank-mounted ignition, and removed the weights and point cam from the camshaft, and will cover that end with a cl77 cam end cover. I cut off the tach drive from the l.h. cam, counter bored the end, and made a tool steel washer to fit the counter bore. I shortened the expander bolt, re-threaded it, and made all to fit under a cl77 l.h. cam end cover. BTW, the weight of the stock points system parts I removed was 269 grams [ about 9.5 oz ].

[LOUD MOUSE]

I also flew model airplanes and set a record in ROW Sept, 24, 1960.
Used a Sal Taibi HYDRO-STAR and a .051 HORNET.
12.56 was the time.
I flew that plane a couple of years later without the floats and with wheels and it did a GIANT LOOP and crashed into the asphalt at Mile Square Garden Grove, Ca. OH WELL!
I later started modifying SUPER TIGER engines, .40 and .65 for free flight and a JOHNSON .29 for Free Flight..
I also used the .40 for Rat Racing which I never lost a event as the plane would pass the others every 5 laps.
Plane had a 3 foot long by 3 inch wing HIGH ASPECT, and fast it was.
Sure was fun and I still have that engine.
For the day 17,400 RPM was pretty good.
The .65 was mounted on a 1000 IN. (7 foot wing) TEXAN designed by Ed Miller and did vertical take offs with ease.
Won many endurance contests with it.
Last flew them in 1966 just before I married my present wife. (got to love her)
I applied the same porting presentable to my 1973 HONDA CR125M then to my 1965 YAMAHA YZ250 MONO SHOCK which I raced both Moto Cross and Open Desert.
Many jealous racers back then both model airplane and MC.
Maybe some day I'll find a warn guide when I use my HONDA pilot and broach to cut new seats.
Nothing so far. .........................lm

Dick

Great sentiment, and I share your interest in investigating and tweaking things. Yes, I fell in love with these bikes at 14 and enjoy both possibilities of building someting as near to factory spec as possiblke AND building something just for me.

These bikes are very malleable and can be tweaked to your preference. I am thinking about building a miniature Laverda SF as a sort of humorous homage to Laverda copying the CB77 design...

Beautiful work on the Chevy engine.... :-)

I also have a small collection of model plane and boat engines. Anything that burns fuel, makes a noise and smells - I'm there......

G

I see you are building a FULL RACE ENGINE.
As there are many folks watching a series of discussion like this one and I see replacing things which I seldom see needing replacement
I ask WHY so others don't think "I have to do that"when they work on their engines/bikes.
I remove the cam bearings by placing them in the jaw of my vise wide enough for the lobe to clear but the sides of the inside race rests on both jaws. BLAM.
I don't use any other valves other than HONDA as when I rebuild heads I make them HONDA STOCK.
I build engines to be easy starting, run like HONDA intended, able to ride for miles at a time with usually nothing more than points adjustment and cam chain adjustment.
I see in your case you are building for POWER now that you have described ALL the PARTS you are CHANGING.
Are you building a VINTAGE RACE ENGINE?. ...............lm

I don't know that it will be a "full race engine", but some things mfr's do are more cost-effective, much to the chagrin of designers and engineers. No doubt a crank-mounted ignition will be more precise than the stock system, and why I am eliminating a half pound of unnecessary rotating mass. I've generally found a little "tweaking" here and there can improve performance and reliability. Besides, I love internal combustion engines, from my model airplane engine collection , to the big block Chevy in my garage [it's not in anything, but I really had fun building it, and am trying to convince my wife to let me set it in the living room with a glass top as a coffee table].
In my opinion, the 305 engine was one of the most aesthetically beautiful engines Honda ever produced, but Honda's casting and manufacturing capability was not then what it is today - hence a few "tweaks" here and there. As a retired toolmaker, I can't leave well-enough alone, and my Super Hawk is going to look some what like a vintage track bike. I have another that will go back to show room stock.
A couple of pics of my 1961 Chevy 348 [first big block], starting with a "before" pic. I had a '61 Impala SS in '68, with the 3x2 set-up - always liked that engine.

Hello Dick.
I have a couple of questions about the guides and cam bearings.
What was the reason to replace the guides?
The wire Cir Clip is a limiter to stop the depth of the guide to an exact depth as the guide is installed from the top.
I've found "2" bad guides in all the heads I've rebuilt.
Both were intake and both had cracked in halt at the lower groove made to allow air to inter when the valve opens. (not much air and after time HONDA removed that from the guide/head.)
All the actual HONDA valves I have are the same as to magnetism. (I have plenty here and they usually have a "B" cast on the head but not all the exhaust but most do have the "B".
All of the intake is steel which is drawn to the magnet.
All of the exhaust will not draw to the magnet.
Beware of the CHEAP after market valves on eBay.
HONDA shows using a piece of wood and rubber mallet to drive the cams out.
I use Brass or Aluminum rod.
Did the 250 degree heat ruin the neoprene on the advance weights?
Do you think there may be a possibility that the steel dome may come loose if the head is heated several times? (I've had 2 leakers and I hadn't heated either of them.)
. ....................lm

Thanks, lm
I am considering making new valve guides from SAE no. 62 hard bronze - an excellent material for severe use. The ends of my guides are pitted, and I am concerned with carbon build up around the stem.
All of my exhaust valves with a "B" are entirely non-magnetic - is that your preference, lm?
250 degrees is only 38 deg above boiling, hot enough for the aluminum to expand, and less than the operating temps of the head. I put a couple of pennies on the point cam under my vise grip jaws to protect it, and the cam came out with little effort. The same for the opposite cam. The cam bearings are a press fit on the cam, and I have always been hesitant driving bearings out, whereby the races and balls take the shock load.
As for the neoprene on the advancer weights, they do not seem to be affected; besides, I am using the Sasche-Elektronic crank-mounted ignition, and removed the weights and point cam from the camshaft, and will cover that end with a cl77 cam end cover. I cut off the tach drive from the l.h. cam, counter bored the end, and made a tool steel washer to fit the counter bore. I shortened the expander bolt, re-threaded it, and made all to fit under a cl77 l.h. cam end cover. BTW, the weight of the stock points system parts I removed was 269 grams [ about 9.5 oz ].

[Dick Eastman]

I sure see a lot of MC folks that were big into model aircraft in their youth! lm sounds like you were seriously into flying/racing models! And off-road, as well! I can tell by your posts that you are certainly an experienced veteran. Super Tigres were the HOT engine to own - I have only one in my collection, a .35C, and bought in 1965 for $12.98, alot of money then for a 15 yr old; in comparison, my McCoy Red Head .35 was $5.95 - flew that in a Sterling RingMaster, and then in a CG Shoestring Stunter. Never competed, but every wkend at the ball field. Got into 1/2A free flight, too. I still want to add a Holland Hornet to my collection, as well as a Johnson. I have a Dynajet Redhead pulse jet engine, and an M.E.W. 307 pulse jet engine, and my latest is a U.K. manufactured Wren 80 Jubilee turbine - idles at 50,000, and maxes at 165,000 rpm, 8 kg of thrust. I'm presently building a Tony Nijhuis [U.K.] DeHaviland DH 100 FB9 Vampire for it, 78" ws. There's just not enough hours in a day...
Like you say, Graham, if it burns fuel, makes noise, and smells, I'm into it! A miniature Laverda SF? That would be too cool! I'll look that up, as I haven't seen one of those for years.

[LOUD MOUSE]

You are correct that I was serious with the model planes and desert racing.
As to the airplanes I competed to win not just fly.
Dad once asked me why I Played With The Toy Airplanes. (worked all his life for BRANIFF AIR LINES and retired as a supervisor in the Engine Shop)
I explained that I would never own a big company, be president of any company but I can become known as a good and fair competitor with competition model airplanes and known to many as that person to beat to win.
The last day I competed was 1965 at SEPULVEDA flood control basin (north of HOLLYWOOD) and as I was walking to a area to setup my tool box and launch my planes from I saw a friend who flew Bill Millers SATELLITE with a feller but the paper design wasn't his design.
(ya could almost tell who's plane was in the air by the paper design)
He greeted me and I responded.
I asked what he was up to as the plane was a different paper design from what he flew.
He was helping a new member of his club adjust his plane to fly.
As I walked on by the new feller asked who I was.
My friend explained that I was Ed Moore and if you are entered in a class I was flying "He would need to beat me to trophy".
I won 3 first places that day and never competed again.
I had accomplished my objective and went on the racing bikes.
At this time I attempt to offer my knowledge of the C/CA/CB/CL 72/77 bikes to any who may need to learn a bit easier than I did starting in 1963. .....................lm

I sure see a lot of MC folks that were big into model aircraft in their youth! lm sounds like you were seriously into flying/racing models! And off-road, as well! I can tell by your posts that you are certainly an experienced veteran. Super Tigres were the HOT engine to own - I have only one in my collection, a .35C, and bought in 1965 for $12.98, alot of money then for a 15 yr old; in comparison, my McCoy Red Head .35 was $5.95 - flew that in a Sterling RingMaster, and then in a CG Shoestring Stunter. Never competed, but every wkend at the ball field. Got into 1/2A free flight, too. I still want to add a Holland Hornet to my collection, as well as a Johnson. I have a Dynajet Redhead pulse jet engine, and an M.E.W. 307 pulse jet engine, and my latest is a U.K. manufactured Wren 80 Jubilee turbine - idles at 50,000, and maxes at 165,000 rpm, 8 kg of thrust. I'm presently building a Tony Nijhuis [U.K.] DeHaviland DH 100 FB9 Vampire for it, 78" ws. There's just not enough hours in a day...
Like you say, Graham, if it burns fuel, makes noise, and smells, I'm into it! A miniature Laverda SF? That would be too cool! I'll look that up, as I haven't seen one of those for years.

[Dick Eastman]

I understand that in later models, Honda discontinued the two fittings under the carbs on the head that were used to create a vacuum draw on the intake valve guides, the idea being it helped to lubricate the intake valve stems. If this proved ineffective, is it necessary to have the intake valve guides grooved inside and outside, with the small joining hole [as seen in Graham's photos above]? I ask, because I am making new guides. The exhaust guides have no provision like this, and are apparently effective on getting oil on the stem, but not to the point it draws oil into the combustion area. The ex. valve stems are also smaller than the intake stems - the guides on both are 7mm.

[LOUD MOUSE]

Not sure the design was to help lube the intake valves.
Some say it was to help remove any moisture that formed while running.
I for one would not add that groove were I making new guides.
If I ever need another guide I have several so no need to make them. ................lm

I understand that in later models, Honda discontinued the two fittings under the carbs on the head that were used to create a vacuum draw on the intake valve guides, the idea being it helped to lubricate the intake valve stems. If this proved ineffective, is it necessary to have the intake valve guides grooved inside and outside, with the small joining hole [as seen in Graham's photos above]? I ask, because I am making new guides. The exhaust guides have no provision like this, and are apparently effective on getting oil on the stem, but not to the point it draws oil into the combustion area. The ex. valve stems are also smaller than the intake stems - the guides on both are 7mm.

[G-Man]

Dick

I believe that the vents were to reduce vacuum created in the inlet port pulling oil down the guide from the cambox to be burned in the combustion chamber. A sort of alternative to putting on valve guide seals as many designs now do.

By feeding air from the air-filter (near atmospheric pressure) the vacuum in the guide is reduced and tendency to draw oil down the guide is also reduced /eliminated.

Because the exhaust port carries air at much higher pressure than the cam box, this is not seen as a problem there. Both inlet and exhaust guides are adqeuately lubricate by spalsh and movement of the valves.

That Honda chose to delete tis feature on later models without using any alternative remedy suggests that it was not really an issue. If you are concerned then you can machine the tops of your new guides to take modern valvce stem seals.

G

I understand that in later models, Honda discontinued the two fittings under the carbs on the head that were used to create a vacuum draw on the intake valve guides, the idea being it helped to lubricate the intake valve stems. If this proved ineffective, is it necessary to have the intake valve guides grooved inside and outside, with the small joining hole [as seen in Graham's photos above]? I ask, because I am making new guides. The exhaust guides have no provision like this, and are apparently effective on getting oil on the stem, but not to the point it draws oil into the combustion area. The ex. valve stems are also smaller than the intake stems - the guides on both are 7mm.