Topic: Pinned rocker shafts cb500

[tennesseebreeze]

Has anyone tried to take the problematic valve rocker shafts on the old 500's and "pinned" them in place kind of like the later 550's? The rocker shafts supposedly tend to spin in the aluminum cover, eventually grinding out the holes eccentrically. If I find the valve cover in mine is of good condition (it looks good from the end, but I've yet to take it off and do a proper inspection), and doesn't have the play that worn covers have- it seems like there could be a way to machine a stop to prevent it from spinning. I read another method where o-rings are pressed between the rocker shaft caps and the end of the shaft. I was looking for something more substantial maybe.

[FunJimmy]

Why not just purchase the updated (pinned) cover and be done with it.
You should be able to find them cheap on eBay

[tennesseebreeze]

Thanks for the response, but that's not the question I asked. The later covers are being snatched up and seem to be going up in price for this very reason. I have been looking at them. Also, why toss a good cover if you can make it last longer by modifications? If a modification can be done to the older covers, it may help others in the future as these parts get more scarce. Call it curiosity, but I'd be interested in ideas other than "just buy one".

[BomberMann650]

Strynboen describes the method to machine the rockerbox assemby in this thread

http://forums.sohc4.net/index.php/topic,157629.msg1806572.html#msg1806572

I've had the notion to get one made into a proper race ready valve cover.

Sounds silly but - apparently it's possible to lighten the rocker arms in these things.  Which can be necessary if you put a really big camshaft in the bike 

[tennesseebreeze]

Strynboen describes the method to machine the rockerbox assemby in this thread

http://forums.sohc4.net/index.php/topic,157629.msg1806572.html#msg1806572

I've had the notion to get one made into a proper race ready valve cover.

Sounds silly but - apparently it's possible to lighten the rocker arms in these things.  Which can be necessary if you put a really big camshaft in the bike 

Ooh, that's hardcore. Leave it to Strynboen to have the balls to try that first. I'm wondering too if a threaded hole could be put right there above the pucks within the pocket, with a set screw and a corresponding flat spot on the shaft. Something to think about.

[BomberMann650]

Orher tbing to consider is getting 4 long rocker shafts installed instead of the 8 short ones.

And the extra pins actually live under the breather cover portion of the box.  Not near the oil pucks

[tennesseebreeze]

Orher tbing to consider is getting 4 long rocker shafts installed instead of the 8 short ones.

And the extra pins actually live under the breather cover portion of the box.  Not near the oil pucks

That makes sense too because instead of pins coming from underneath (where they are more apt to fall into the valve train), they are seated up top, where there is no where to fall. I was just putting arrows on this picture where I thought they might go. If done this way, you'd have to ensure those pins or set screws had heavy thread lock on them.

[FunJimmy]

Thanks for the response, but that's not the question I asked. The later covers are being snatched up and seem to be going up in price for this very reason. I have been looking at them. Also, why toss a good cover if you can make it last longer by modifications? If a modification can be done to the older covers, it may help others in the future as these parts get more scarce. Call it curiosity, but I'd be interested in ideas other than "just buy one".

Suit yourself but you've already spent more time than it cost to purchase the factory update.
What's your time worth? Peanuts it would seem.

[BomberMann650]

Jimmy, these 77+ rockerboxes are an elusive creature.  Becoming as rare as sohc 650 camshafts.

Unless you happen to know someone sitting on a horde of them and aren't sharing with the group?

[tennesseebreeze]

Thanks for the response, but that's not the question I asked. The later covers are being snatched up and seem to be going up in price for this very reason. I have been looking at them. Also, why toss a good cover if you can make it last longer by modifications? If a modification can be done to the older covers, it may help others in the future as these parts get more scarce. Call it curiosity, but I'd be interested in ideas other than "just buy one".

Suit yourself but you've already spent more time than it cost to purchase the factory update.
What's your time worth? Peanuts it would seem.

You aren't just unhelpful. You're also another fragile forum know-it-all who doesn't play well with others. Get bent.

[tennesseebreeze]

And how much is your time worth Jimmy? You take the time out of your day to comment on a thread twice now trying to change the subject at hand.

[FunJimmy]

And how much is your time worth Jimmy? You take the time out of your day to comment on a thread twice now trying to change the subject at hand.

Ok, you got me. I'm sorry for trying to offer an opinion. You're probably not as obsessive about perfection as I am.
It's been a life long burden that has cost me countless hours and hundreds of dollars trying to make things the absolute best I can.
Maybe that's why I would buck up and get an evolved rocker cover with fewer shafts and NO wear issues.
Sure you can fix it. He!!, you can fix worn cam bearings too. But why would ya? Another opinion and we all know about opinions, right?

[strynboen]

it is a hard job to re make this covers...thats vhy i dont have done any yet
..still try to find a more easy and less kosty vay.


..think jimmy is right,,,as long you can find covers for sale..its the easyest and best..vay..machining is time and Money costy

..use o rings to Lock a old type shafts or/and,, thange to long shafts..vhenits not is veared aut yet ..is a vay to help youself..and thange oil often..so all grinding materials is aut of the engine...better use a bit less expensive oil..and thange it tvice as often..is my best advice

but still dont throw the old veared covers to scrap...someday ve find the easy less expensive vay to make them ..

[alacrity]

IF one could find a near perfect cover for under $100, it's WORTH IT.  But that's the rub ... anything with more than 10k on it is at risk of already being messed up, because all it takes is for a PO to mess up a valve adjustment or cover reinstallation (after a top end job or cam change), and the constant incorrect pressure on the rocker shoves the shaft into the housing and it galls.  So any used cylinder head cover is an unknown proposition, and sellers aren't gonna be able to truly test if it's perfectly round/in spec as per OEM requirements when new.

SO... Some Machinist (as I requested and posted here before) COULD POTENTIALLY create a reasonable little business machining and installing brass bushings in these plain aluminum tunnels.  Send a cover and some amount of money that is reasonable, get back a cover that is good for 100,000 miles (or even 100,000km would be fine).  There are hundreds of us out there with these bikes facing this issue...  And this bushing fix would solve it for every cb500 and 550 owner (and also cb350 and 400 owner as well)  Right?

[alacrity]

yeah,... I guess I was hoping someone had a rig where they already were doing something like this for something else, and could easily adapt their machine tools, spool up and whip out 5 at a time of these.  Would I pay $150 or even $200 for a "done" cylinder head cover that I knew was perfect and would last? Yes, given the hassles and time suck and frustrations I've had with the last two.  Would others? dunno.

[BomberMann650]

I think ya'll are way overcomplicating the procedure.  We're talking about little bits of relatively soft metals.  I'd do the work myself with a hand drill if I could get the thing to run a straight line back and forth.  The outer ends of the holes are still round so it's not like you need a lazer sight to center the bit.  The bushing doesnt need to be thick.  Just enough to unfcuk the shaft bore.  Punch some holes down for a securing screw in the post 76 factory positions.  Press the brass in with some oil resistant bonding agent and reassemble the rocker arms.  Done.  I'd bet it's a two hour job after we finish arguing over what needs to be done 

[scottly]

You're also another fragile forum know-it-all who doesn't play well with others. Get bent.

Where do you get this "fragile" stuff from? You are the one that gets butt-hurt when anyone offers a different opinion.

[BomberMann650]

You're also another fragile forum know-it-all who doesn't play well with others. Get bent.

Where do you get this "fragile" stuff from? You are the one that gets butt-hurt when anyone offers a different opinion.

Gentlemen...please.

There are rules.

[FunJimmy]

I think ya'll are way overcomplicating the procedure.  We're talking about little bits of relatively soft metals.  I'd do the work myself with a hand drill if I could get the thing to run a straight line back and forth.  The outer ends of the holes are still round so it's not like you need a lazer sight to center the bit.  The bushing doesnt need to be thick.  Just enough to unfcuk the shaft bore.  Punch some holes down for a securing screw in the post 76 factory positions.  Press the brass in with some oil resistant bonding agent and reassemble the rocker arms.  Done.  I'd bet it's a two hour job after we finish arguing over what needs to be done 

I know it sounds easy but those shafts need be perfectly perpendicular to the valves or the rockers will side load and burn up the cover at an accelerated rate. Then the next owner will start another "PO did shifty work" thread and we wouldn't want that.

[That 70s Bike]

Back in the 70's when my '74 550 did this, I bought a new cover for ~$50 (halfhill.com=$220 in today's money) I thought about set screws through the top with lock-tite, later I sold the bike.
Having another 550 now I won a N.O.S. cover on ebay but it's pre-1977. It would be nice to modify it to not self destruct.
This crap design is why I quit motorcycling for decades & boycotted Honda, I could not afford design sabotages.

[RAFster122s]

Problem is Honda didn't design it to sabotage...they just took a long time to figure out a good fix.
Like most any company, they learn from their mistakes or they go out of business.  Honda apparently has been able to learn enough to continue to have a motorcycle company.

Not wanting to argue...and I'm not going to.  Just merely pointing out a fact that hind sight is 20-20. 
These bikes were made in a era where the methods and materials and knowledge was growing at a healthy clip. Honda started using thermoplastics long before other companies and learned how to do them well. It lowered their production costs in time.  They employ other techniques and methods to improve over time.  They never set out to put out an inferior product, few companies do...it could be argued today that several companies or entire segments of industry do produce product that is inferior or has designed obsolescence to sell future units.  That mindset changed a few decades ago...

If anyone has a later ('77-78 CB550) cover they want to sell, I have my hand up wanting one...

David

[BomberMann650]

Too damn early in my day to go on with this discussion.

Why would a warped head cover even be considered a candidate for this?

There's a Donald Trump joke to be had there.  But i digress

[alacrity]

Funny. I began a response with PRECISELY the same phrase, "It's not about a warped cover...."  Haha.
Here's video I just shot showing the problem precisely.  This just came in via eBay. Seller said it was in very good condition.  Cam journals are perfect, the rocker faces are all good if not great.  This one has the short shafts.  And on the intake side, same place my current one has a problem, I have this really ugly fat wiggle.  So this cover is garbage until I can figure out a machining/bushing solution.

video is here:  https://vid.me/e9RD

[FunJimmy]

Funny. I began a response with PRECISELY the same phrase, "It's not about a warped cover...."  Haha.
Here's video I just shot showing the problem precisely.  This just came in via eBay. Seller said it was in very good condition.  Cam journals are perfect, the rocker faces are all good if not great.  This one has the short shafts.  And on the intake side, same place my current one has a problem, I have this really ugly fat wiggle.  So this cover is garbage until I can figure out a machining/bushing solution.

video is here:  https://vid.me/e9RD

It look simple enough but what tolerance does the inside bushing have?

[alacrity]

No idea. I am neither a machinist nor engineer.  Just a creative mechanic with a problem that needs solving

[FunJimmy]

Sorry. I wasn't very clear with the previous question. The outside shaft/bushing clearance is obviously loose as shown in the video.
It looks like a simple fix as the OP (and others) have suggested but what condition (clearance) does the other (inside) shaft bushing have?
I would expect them both to be out of tolerance and that would complicate the simple bushing replacement suggestion.

[alacrity]

It seems to me that the inner tunnels retain their shape because of all the metal around them... the supporting structure is stronger.  These all seem to have a problem in the same place... around the Number 1 piston intake side.

[RAFster122s]

I've wondered if it would require you to mill for a bushing for the entire path of the rocker shaft. Could you get away with milling or drilling and reaming from the outside to only cover 1/2 of the #1 and #4 rocker shafts?
Once they start wearing their oval shape into the cover, then you start wearing the rocker arm adjusters and the rocker faces as well as the cam.

Being able to fit the longer shafts into #1 & 2 and #3 & 4 could stablize the shafts by their longer length.

Maybe my idea is full of smelly excrement...just seemed like it could be a viable fix.  But, to make it viable cost wise you would have to have access to the machines and have the training to do it, or have someone who basically wanted to work for free for a better good of CB owners.  Not likely.  Given the one resource that we all have which is limited and non-renewable is time.

David

[RAFster122s]

Cal, very true, the setup is the huge time sink, but the cutter lengths are a challenge and I was just thinking of how to minimize the length needed for the bushing operation.  Maybe a solution before they go bad is to rework it so they can accept long shafts instead of short shafts. It won't be as easy to wear a long shaft due to the moment arm involved and the added surface area.


But, as long as you can get the '77 and '78 cam/rocker covers, that is by far the best solution.


I'm looking for one of the late covers but don't have a lot of funds for one to outbid anyone when they go for well over $100 on ebay.


David

[scottly]

This same topic came up a few years ago, and the least expensive repair appeared to be using set-screws from the outside of the cover to force the shafts down into the bottoms of the bores, where the wear is the least. IIRC, the question was if there was enough material for threading the screws to support the load of the valve springs? I offered to see if it was a feasible repair, but no one was willing to sacrifice a cover to the cause.

[That 70s Bike]

Problem is Honda didn't design it to sabotage...they just took a long time to figure out a good fix.
Like most any company, they learn from their mistakes or they go out of business.  Honda apparently has been able to learn enough to continue to have a motorcycle company.

Not wanting to argue...and I'm not going to.  Just merely pointing out a fact that hind sight is 20-20. 
These bikes were made in a era where the methods and materials and knowledge was growing at a healthy clip. Honda started using thermoplastics long before other companies and learned how to do them well. It lowered their production costs in time.  They employ other techniques and methods to improve over time.  They never set out to put out an inferior product, few companies do...it could be argued today that several companies or entire segments of industry do produce product that is inferior or has designed obsolescence to sell future units.  That mindset changed a few decades ago...

If anyone has a later ('77-78 CB550) cover they want to sell, I have my hand up wanting one...

David

Indisputable fact is: during this time the 750's shafts were locked from movement. They knew why they did this and why they did not for the CB-500/550 for 6 of the 8 year run. Foresight not hindsight.

[strynboen]

Problem is Honda didn't design it to sabotage...they just took a long time to figure out a good fix.
Like most any company, they learn from their mistakes or they go out of business.  Honda apparently has been able to learn enough to continue to have a motorcycle company.

Not wanting to argue...and I'm not going to.  Just merely pointing out a fact that hind sight is 20-20. 
These bikes were made in a era where the methods and materials and knowledge was growing at a healthy clip. Honda started using thermoplastics long before other companies and learned how to do them well. It lowered their production costs in time.  They employ other techniques and methods to improve over time.  They never set out to put out an inferior product, few companies do...it could be argued today that several companies or entire segments of industry do produce product that is inferior or has designed obsolescence to sell future units.  That mindset changed a few decades ago...

If anyone has a later ('77-78 CB550) cover they want to sell, I have my hand up wanting one...

David

Indisputable fact is: during this time the 750's shafts were locked from movement. They knew why they did this and why they did not for the CB-500/550 for 6 of the 8 year run. Foresight not hindsight.

yes ,,,but at same time 400 vas made vith absolut no problems..just a sleigtly better oiling system(sprayers in the cam areia)..but ok a smaller engine ..less pressure at the../valvet lifters.

[alacrity]

again - what value is there in raking Honda over 40 year old coals?
Let's figure out how to FIX the problem now...

[BomberMann650]

There have been a couple of simple tricks shared on here.  Tricks to keep the good valve covers good at least.

Though not everyone knew about the extra o-ring method before.  As evidenced by the wandering rocker shaft on my recently acquired motor core. 
Oh well, I bought it because the cooling fins had nary a mark on em.