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?

[calj737]

It is my practice to have the shafts (as long as they're good) treated with Dry Film Lubricant. This doesn't prevent them from spinning or rotating, but does significantly reduce their friction to the tunnel. I may tinker with a bushing fix, but...

The problem as I see it is not the production of the bushing, but the reaming of the tunnel to accommodate the bushing. The shaft has to remain the same OD, so there's essentially no room left without enlarging the current hole. Turning a bushing on a lathe and pressing it in is small potatoes. Enlarging the hole (requires a special fixture to hold it on a mill) and a very long reamer (expect that to cost over $200 bucks alone) and the machine time, and now you're talking about a pricey repair. Even amortized across 20 covers, the setup and machine time is probably 4 hours for the milling. The bushings another 1 each (8 by my count) and now you're into the $600+ range even at super cheap shop rates.

So I'm not sure it can be done cost effectively. Not without using a CNC lathe to cut the bushings (then you have their machine time and programming to account for too) and some willingness to tinker with it.

I put this (I do think its a very good idea by the way) into the same category as remaking the engine mounting bolts out of stainless. But that too costs well over $100/set due to the machining and material. If you need to make them for yourself, thats one thing. But to make and resell, well we all know how cheap some CB owners are 

[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.

[calj737]

I don't think you could get it done for $150-$200. The amount of time for both the bushings and milling the cover is pretty extensive. I made a drive post guide for someone recently. Took me hours to do a single one on a lather due to the amount of turning, and steps, and machines needed. When machining parts, nothing happens fast if it has critical measurements.

[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

[calj737]

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.

The assessment of things being "easy and simple" are exactly why you're wrong. Jimmy points out correctly, getting and keeping it perfectly square is the trick. Nobody said milling aluminum is difficult. But setting up the existing cover (which is anything but flat) to insure 100% plumb through all shaft holes, then boring it out, then reaming it to an exact ID, then pressing in a bushing (which by the way takes time to make) and then flipping the cover and setting up for pinning. 2 Hours? LOL. You obviously have never worked on a mill or a lathe.

Grab a cover, find a local machine shop, and take it to them for a price estimate. I bet you can't find one to even touch the job, let alone do it for less than $500.

[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