Topic: Who do I have to Screw in order to keep those tappets tight?!!

[BomberMann650]

ok i'm not so sure about the "more seasoned" part but... you need a cover from a k3 or f2. it will fit no matter if f or k model, the covers and heads are the same. if you want to know up exactly when the switch happened look up the parts list for the engine number but k3 and f2 both have the pinned rocker shafts.
your cover is toast, it's actually much worse than mine was. getting one from a k3 or f2 will solve your noisy tappets problem.

Yeah, I figured that intake side rocker shaft was waaaayyy out of alignment.  I've found some replacements on fleabay that should be suitable.

And my buddy at the powersports shop happens to have a machinist on call that could repair and mod the cover I have.  Strynboen's mod could salvage what I have.

Hopefully Ebay will refund some of the money I spent ordering the wrong shocks (oops) so I can afford the rockerbox soon.

[Bootsey]

This video shows a possible fix, depending on how far gone the cover is. (

If I remember correctly, the early 550's have 8 shorter rocker shafts. The later 550's, as well the CB500's have 4 longer shafts, which being longer may help resist some of the pressure and subsequent wearing of the cover better than the shorter shafts, at least in earlier style covers that don't have the locating pins. I replaced my short '75 550 shafts with some longer ones from a CB500.

[BomberMann650]

Well I know what I must do.

Thanks everyone, bloo and I appreciate the wisdom!

[strynboen]

yes put longer shafts in..and drill and tredden the holes for schrev bits...can stabilice the shaft..but..heat and vibrasion can free the small schrevs..and ruin the engine.

.horensontal drilled and veld bushings inn..use longer shafte..and Lock them is the korrekt vay to do the job the easy and kvik is baying a better top cover

[BomberMann650]

I'm pouncing on a spare motor from a 77cb - local seller good price.

[alacrity]

I also have a cyl head cover with long shafts and no locking pins on one of the project engines.  It has slop on the number 1 intake.
I had this idea to use "the right" amount of brass bushing sheet, a few hundredths thick and create a supportive "collar."  I wonder if that would help hold the end of the shaft in place where the tunnel has ovaled.   I am thinking that if I heat the cover (expanding it), and freeze the shaft and bushing wrap prior to installation, it oughta mate up nicely when the heat transfer completes.  And also I would leave extra bushing stock sticking out of the tunnel on the outside edge so I can peen it into place and not have it migrate in and start dancing with all those moving parts. The trick is gonna be to measure accurately what thickness to get. How to do that. Hmmm.

Whaddya think?

[Gene]

I don't have the skills to do what you're undertaking but had much the same notion - a sleeve.  Let us know how it turns out. 

In the meantime I have a line on a cover, possibly - same issue, #1 intake - pre 76 550.  It's not horrible, but I want to fix it before it becomes so.

[BomberMann650]

I also have a cyl head cover with long shafts and no locking pins on one of the project engines.  It has slop on the number 1 intake.
I had this idea to use "the right" amount of brass bushing sheet, a few hundredths thick and create a supportive "collar."  I wonder if that would help hold the end of the shaft in place where the tunnel has ovaled.   I am thinking that if I heat the cover (expanding it), and freeze the shaft and bushing wrap prior to installation, it oughta mate up nicely when the heat transfer completes.  And also I would leave extra bushing stock sticking out of the tunnel on the outside edge so I can peen it into place and not have it migrate in and start dancing with all those moving parts. The trick is gonna be to measure accurately what thickness to get. How to do that. Hmmm.

Whaddya think?

Good idea...but the issue is that wear creates more of an egg-shaped hole.

Still have a facilitated need to do a little horizontal drilling thru the rocker head.  Just as strynboen described.

All this talk makes me wanna get some schooling on machinist skills.

[BomberMann650]

Oh, i think i realized why it's the intake shafts that get worn before the exhaust side.

The valve head is bigger, ergo more weight.  More weight = more force

[strynboen]

yes and prob less oil.in the intake side..cbx engines have some rubber plates vho barikades and hold oil to the heigher cam"s..so Honda vas thinking..and solvent the problem and made improving on later types engines

[BomberMann650]

I was under the impression the oil was mostly splashed out of the center bath by the cam lobes?

Do the oil jets have passages thru the rocker shafts that I failed to notice before?

[strynboen]

use a long shaft.(12 mm)..and drill a small hole and brass veld a small Tool bit cutter in the hole...and you have a nice shaft driller..try to drill through the tunnel ..to get a long run..use car front screen kleaner as lube..it is( sprit alcohol)..it make the aluminium not burn on the cutting Tool..a common problem machining in aluminium

[strynboen]

cb 400 have a cam" bath"..vho drip the cam lobesin oils..and some sprayers vho help oiling all.
.they dont have the same problems vearing aut the shafts..
i think 500 550 have internal oill lines in the cams..i dont have a 550 cam at my shop..the( 400 cam is solid)

but still the 400 holds better up

[BomberMann650]

Good advice strynboen!

I remember seeing oil passages in the cam recesses, but not much elsewhere.

[strynboen]

this is vhy i dont bay expensive oil...but thange often..and thange filter at same time..this engines need a klean oil...not a advanced ++party oil..
dirt in the oil is the killer..on all sohc bikes

[alacrity]

+1

[That 70s Bike]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

[alacrity]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

This is beyond unhelpful.  Why are you even in here?

[alacrity]

Ya'll were correct in your assumption.

The intake shafts have a bit of a lean goin in their groove.  Exhaust shaft seems normal enough.

do this test - https://vid.me/e9RD

[That 70s Bike]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

This is beyond unhelpful.  Why are you even in here?

When you make Moderator I'll answer to you.
It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969. They chose not to for the 1971-73 CB-500, 1974-76 CB-550 (6 yrs) then finally fixed it for 1977-78 There was no recall to fix any of the previous bikes.

[seanbarney41]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

This is beyond unhelpful.  Why are you even in here?

When you make Moderator I'll answer to you.
It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969. They chose not to for the 1971-73 CB-500, 1974-76 CB-550 (6 yrs) then finally fixed it for 1977-78 There was no recall to fix any of the previous bikes.

totally wrong about that one bro...cb750 rocker shafts were unlocked from the start until '72 and the unlocked rockers have proved to be more durable and make slightly more horsepower and were only locked to quell noisy valve train complaints.  Many late cb750 builders will convert to the early rocker towers in order to use the unlocked shafts, if they can get ahold of the parts. 

I have seen plenty of 500/early 550s going strong with their original valve trains at 40-50,000 miles, so maybe you might want to cast the blame on someone other than Honda...previous owners who don't change their oil perhaps?

[scottly]

It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969.

Are you sure about that?

[That 70s Bike]

It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969.

Are you sure about that?

No! I assumed it when Honda's Parts Staff said it in '75 as I was shelling out for a new cover for a '74 550.

[alacrity]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

This is beyond unhelpful.  Why are you even in here?

When you make Moderator I'll answer to you.
It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969. They chose not to for the 1971-73 CB-500, 1974-76 CB-550 (6 yrs) then finally fixed it for 1977-78 There was no recall to fix any of the previous bikes.

What I meant is in line with what this whole site is about:  making the old stuff work and enjoying it for what it is.   What good does it do to rail against a management team that has been retired for decades and is by now mostly dead? How does it help anyone for you to curse out Honda as a brand and whine that there wasn't a recall.  Seriously. Do you think someone at Honda will read your rant and suddenly send you money or parts?  Do you think everyone who has one of these bikes will just abandon it or set it on fire?  If you are gonna be part of US, then contribute, be helpful, be supportive.  Use your experience for the good of others.  Come up with a useful suggestion about how to deal with what we face now with these covers, or stfu.   

[That 70s Bike]

To answer the question in your Subject Heading:
You need to screw HONDA, just like they did their 550 patrons.
The Honda parts guy told me in 1975 when I bought a new cover that the 750's have locks on the shafts.

This is beyond unhelpful.  Why are you even in here?

When you make Moderator I'll answer to you.
It is helpful, Honda knew to lock the 750 rockershafts since their first 4 cylinder CB-750 in 1969. They chose not to for the 1971-73 CB-500, 1974-76 CB-550 (6 yrs) then finally fixed it for 1977-78 There was no recall to fix any of the previous bikes.

What I meant is in line with what this whole site is about:  making the old stuff work and enjoying it for what it is.   What good does it do to rail against a management team that has been retired for decades and is by now mostly dead? How does it help anyone for you to curse out Honda as a brand and whine that there wasn't a recall.  Seriously. Do you think someone at Honda will read your rant and suddenly send you money or parts?  Do you think everyone who has one of these bikes will just abandon it or set it on fire?  If you are gonna be part of US, then contribute, be helpful, be supportive.  Use your experience for the good of others.  Come up with a useful suggestion about how to deal with what we face now with these covers, or stfu.

stfu? who the hell are you? You're not in charge of this forum. I made a reply to the OP's question (Subject), and nobody but YOU, gets snide, as if this is YOUR Forum. Please seek councilling instead of disrespecting members that you don't agree with.