Topic: How to Check for Rocker Shaft Wear?

[Paul Bater]

Sorry, its me again.

As I'm probably going to go and check out this 75 CB550 I'm interested in, and having searched through the forum on rocker shaft wear (and scared myself snotless at how much it costs to fix), I had a few questions. Figuring I can't really take apart his bike on his driveway, the only way I think I can check out this problem is by removing the caps on the side of the valve cover? Assuming that's correct, what am I looking for? Are there any noises associated with this when its running or idling? Does this effect a lot of earlier 550's or just a few here and there? I get the impression that most of the engines survived ok, but a few have this costly problem.

The bike has about 19000 miles and has had two mature owners for the past 25 years that seem to have been anal retentive with maintenance, if that helps any. It did sit unused in a garage for about 2-3 years with no use before it was cleaned up and made to run happily again.

Thanks again, Paul

[bryanj]

Not all 550 had a problem, unless there is a lot of top end engine noise dont worry. The upgrade was fitted from engine number 1083641 in the K modle and 1133172 in the F model+.
You can tell if it the new one by taking off the top breather cover and if there are four nuts and washers it is the "new" type.
Also there are so many used covers about and its not a difficult fix--2-3 hours at most to swop.

[Paul Bater]

Great, thanks Bryan. I'll check for that when I go take a look.

[TwoTired]

As bryanj states not all 550s had this problem.  In the US, the factory improved covers occurred mid to late 76 production.  So, it is likely your bike bears scrutiny.

The bad ones I found from on bike inspection were most effected on the #1 cylinder side, (the left).  The first one I found WAS making noise, as the rocker was hitting the inspection hole cover.  This was also the worst one I found.
To inspect, the cam cover end cap must be removed.   This cover contain two plugs with orings, that fit into the rocker shaft access holes.  With the end cover removed, you can see the ends of the rocker shafts.  The shafts have a threaded hole in them, used for shaft extraction.  If the cover is worn, this hole will appear uncentered in the shaft bore.  The valve spring pressure, plus cover wear, makes the shaft move up higher in the cover.  Wear such as in the picture below, allows the rocker to twist, placing high wear loads on the cam and cam follower, causing early failure of those components as well.  It takes a lot of miles before actual engine performance suffers, though.

[Paul Bater]

Two Tired, thats great, thank you. A picture is worth a thousand words.

[OldSchool_IsCool]

I'm looking at a '73 550 with 21K miles (not sure it it's an F or a K, single muffler, but probably not stock).  I'll definitely look under the left cam shaft inspection cover to see if the gap in TT's photo is present.  Probably a compression test and general inspection.  Anything in particular I should look for?

[TwoTired]

I'm looking at a '73 550 with 21K miles (not sure it it's an F or a K, single muffler, but probably not stock).  I'll definitely look under the left cam shaft inspection cover to see if the gap in TT's photo is present.  Probably a compression test and general inspection.  Anything in particular I should look for?

A US model 73 would be a CB500.  Clutch cable left hand side of motor.
A US model CB550 would be 74 at the earliest. Clutch cable right hand side of motor.

Both would be K models and had 4 into 4 factory exhaust.
F models would be 75-77, had chrome 4 into 1 with swoopy head pipes all going to the right of the oil filter.

You might look to see if the engine has been gouged by an o ring chain near the front sprocket.

Cheers,

Cheers,

[OldSchool_IsCool]

Thanks for your reply, TT.  I'm thinking now he has a frankenbike there.  He posted one pic of the odometer/speedometer.  The speedometer tops out at 140 and has no trip odometer.  The 140 top end would indicate F, correct?  If so, then it obviously isn't original or he has the model/year way off.  Also, the indicator lamp panel is a straight bar mounted below the clocks, not the triangular arrangement like my '77.

Is rocker shaft wear an issue for the 500 engine also?

I'll see if he will email me the serial numbers of both the frame and the motor.

[bryanj]

The only speedo i have experience of without a trip meter is the "Small" one from the cb450 that is identical to the cb500 K0 and K1 (also all uk K2) except no trip

[OldSchool_IsCool]

Hmmm.  The speedo in the pic is definitely small.  OK, milage is not to be believed. 

The owner sent back that the frame number is cb5501013740 and engine number is CB550E-1013828.  A 550 frame and engine, but, according to the 550 modle guide, it's a '74, not '73.  The engine number suggests it does NOT have the rocker shaft "fix" from the factory.  What is involved in repairing/preventing shaft wear? 

It's a non-runner and he wants $250 for it.  I have yet to see the bike up close, but my impression so far is it's right at the border between project bike and parts bike.

[TwoTired]

Hmmm.  The speedo in the pic is definitely small.  OK, milage is not to be believed. 

The owner sent back that the frame number is cb5501013740 and engine number is CB550E-1013828.  A 550 frame and engine, but, according to the 550 modle guide, it's a '74, not '73.  The engine number suggests it does NOT have the rocker shaft "fix" from the factory.  What is involved in repairing/preventing shaft wear? 

It's a non-runner and he wants $250 for it.  I have yet to see the bike up close, but my impression so far is it's right at the border between project bike and parts bike.

None of the CB500/550 had factory speedometers marked with 140.

It's the cam cover that actually wears and loses aluminum.  Another cam cover is the fix, preferrably from a 77 or newer model.  Severe wear will also require a camshaft and rockers, as well.

Prevention of wear:  Mike Nixon told me that adding extra O rings behind the shaft plugs would stop rocker shaft rotation and subsequent wear.  I did this to one 550 that I also replaced the cam cover (old style, $300 new from Honda).  I sold the bike before I could evaluate the effectiveness of the fix.  But, the theory is sound.  I thought it was worth a try.

Cheers,

[vrenlos]

Hmmm.  The speedo in the pic is definitely small.  OK, milage is not to be believed. 

The owner sent back that the frame number is cb5501013740 and engine number is CB550E-1013828.  A 550 frame and engine, but, according to the 550 modle guide, it's a '74, not '73.  The engine number suggests it does NOT have the rocker shaft "fix" from the factory.  What is involved in repairing/preventing shaft wear? 

It's a non-runner and he wants $250 for it.  I have yet to see the bike up close, but my impression so far is it's right at the border between project bike and parts bike.

None of the CB500/550 had factory speedometers marked with 140.

It's the cam cover that actually wears and loses aluminum.  Another cam cover is the fix, preferrably from a 77 or newer model.  Severe wear will also require a camshaft and rockers, as well.

Prevention of wear:  Mike Nixon told me that adding extra O rings behind the shaft plugs would stop rocker shaft rotation and subsequent wear.  I did this to one 550 that I also replaced the cam cover (old style, $300 new from Honda).  I sold the bike before I could evaluate the effectiveness of the fix.  But, the theory is sound.  I thought it was worth a try.

Cheers,

Sorry to dredge up an old topic, but I'm pretty sure this is exactly what's happening with my 550k1.  I originally thought that I did a bang-up job on adjusting the #1 intake tappet, but I opened it up and rechecked and it's spot on.  Time to pull that cam cover and take a look I suppose. 

TT, any idea what size those O-rings were?

[TwoTired]

TT, any idea what size those O-rings were?

I used the same ones that are used on the end cap plugs.

Cheers,

[sixthwisconsin]

Saw this linked in another recent post regarding air box boots. The topic seems way off of the OP topic so I thought I would ask my question here.

Can someone tell me if this is the updated cover?

[oldfart]

Hmmm.  The speedo in the pic is definitely small.  OK, milage is not to be believed. 

The owner sent back that the frame number is cb5501013740 and engine number is CB550E-1013828.  A 550 frame and engine, but, according to the 550 modle guide, it's a '74, not '73.  The engine number suggests it does NOT have the rocker shaft "fix" from the factory.  What is involved in repairing/preventing shaft wear? 

It's a non-runner and he wants $250 for it.  I have yet to see the bike up close, but my impression so far is it's right at the border between project bike and parts bike.

None of the CB500/550 had factory speedometers marked with 140.

It's the cam cover that actually wears and loses aluminum.  Another cam cover is the fix, preferrably from a 77 or newer model.  Severe wear will also require a camshaft and rockers, as well.

Prevention of wear:  Mike Nixon told me that adding extra O rings behind the shaft plugs would stop rocker shaft rotation and subsequent wear.  I did this to one 550 that I also replaced the cam cover (old style, $300 new from Honda).  I sold the bike before I could evaluate the effectiveness of the fix.  But, the theory is sound.  I thought it was worth a try.

Cheers,

Hmmm.  The speedo in the pic is definitely small.  OK, milage is not to be believed. 

The owner sent back that the frame number is cb5501013740 and engine number is CB550E-1013828.  A 550 frame and engine, but, according to the 550 modle guide, it's a '74, not '73.  The engine number suggests it does NOT have the rocker shaft "fix" from the factory.  What is involved in repairing/preventing shaft wear? 

It's a non-runner and he wants $250 for it.  I have yet to see the bike up close, but my impression so far is it's right at the border between project bike and parts bike.

None of the CB500/550 had factory speedometers marked with 140.

It's the cam cover that actually wears and loses aluminum.  Another cam cover is the fix, preferrably from a 77 or newer model.  Severe wear will also require a camshaft and rockers, as well.

Prevention of wear:  Mike Nixon told me that adding extra O rings behind the shaft plugs would stop rocker shaft rotation and subsequent wear.  I did this to one 550 that I also replaced the cam cover (old style, $300 new from Honda).  I sold the bike before I could evaluate the effectiveness of the fix.  But, the theory is sound.  I thought it was worth a try.

Cheers,

Worked fr my owne CB500 that ended up with 94,000 miles.  I was the common Honda mechanic fix back then, and since I was a Honda mechanic, that is what I did.  :-)

Mike Nixon

[TwoTired]

Saw this linked in another recent post regarding air box boots. The topic seems way off of the OP topic so I thought I would ask my question here.

Can someone tell me if this is the updated cover?

I can tell you it is the old, non-updated style.

[lone*X]

A picture is worth a thousand words! Or so they say.  This is the upgraded cover that is most desirable.  This one came off a late 76F spare engine and is going on my 75K engine which has less miles but some visible wear in the left shaft area.  No, it isn't for sale.

[fmctm1sw]

Nice.  I mentioned this in another thread and someone correctly pointed out what it was.  The curious thing is that 550F had a very low serial number (XXX..555 IIRC).  Someone must have updated it.  It's on my 550K top end now...

[dave500]

if you remove an end cover cap and look at the shafts end the updated type has a slot so you can turn it to align the cotter bolts to lock it,the older type is just flat.

[sixthwisconsin]

Thanks everyone...

Installed the extra O rings this morning. I didn't see any signs of excessive wear on my 17k 550k0 and am not having any issues. I'll call it an ounce of prevention.

[That 70s Bike]

Just an FYI
The "improved" covers must be used with the "improved" shafts (not the original 8 single rocker shafts). "Improved" shafts are double length, as only 4 lock bolts were put at the inside ends (under the breather cover) & these new shafts also have a flat area where a flat sided lock bolt mates with it.

And do not throw those old worn covers away! The day will come when someone will post a do-able fix to push the shafts back down, in the few worn holes and get many more miles out of the only covers left. Even putting a double length shaft could negate some of the worn spots as the unworn holes will realign it & if both could support the additional load. How about an "improved" end cap that screws into the threaded shaft ends to help support it. Sound too shade tree? No worse than Honda's original design by professional engineers for this $1800 bike that would cost 9,000 inflation adjusted dollars today It's cooler than the GM 3800- V6 with an aluminum cam gear & plastic teeth. Exact replacement gear (in '93) from GM was $90 or NAPA had a steel one for $15!!!

[Bootsey]

Hey all,

Apologies for digging up such an old thread, but I had a question regarding potential rocker cover wear.

I've got a 1975 CB550K, so obviously doesn't have the pinned shafts. There doesn't seem to be any wear in the cases from the shafts as shown in the earlier photos in this thread.

Just wondering about the mention of adding additional orings to the end cap dowel pins. Just wondered if someone could clarify where to add the additional orings? The shafts have a recess cut to locate the original orings, have people just stacked additional orings there? Do these extra orings take up any additional clearance, to stop the shafts from being able to move and subsequently wear the case?

If anyone is able to share any info, it would be greatly appreciated.

[HondaMan]

Saw this linked in another recent post regarding air box boots. The topic seems way off of the OP topic so I thought I would ask my question here.

Can someone tell me if this is the updated cover?

I can tell you it is the old, non-updated style.

TT:
What would you estimate the chances are that one could make custom bronze bushings to fit into the worn (early) 550 covers and 'recover' their use again?

[TwoTired]

TT:
What would you estimate the chances are that one could make custom bronze bushings to fit into the worn (early) 550 covers and 'recover' their use again?

Pretty good, I expect, provided the machinist has good skills.  Centering the bushing properly into the worn hole would likely be the challenge, and then maintaining center while reaching into a depth of 6 to 8 inches, probably requires a custom cutting tool.

[dave500]

gday bootsey,to check if you do or don't have locked shafts just remove one of those rocker end covers with the single Phillips screw,you can see the end of the shaft,itll have a tapped thread inside it provided to engage a bolt into to withdraw the shafts,if it also has a slot its the locked type,the slot is so you can align it up with a screw driver and get the tapered bolt into the flat section on the shaft.

[Bootsey]

Hey Dave. I've had a lock at the shafts and cover, and it doesn't have the pinned shafts. I was just wondering about the earlier comments in this thread about adding extra o-rings onto the end covers to prevent wear happening on these older style ones? Have you done this on yours at all?

[dave500]

no,im not convinced that under heat and high pressure they'll stop them moving,might at first but they'll flatten and go hard?also no point in doing it to already worn ones?grub screw sounds good.

[Bootsey]

Yeah, true. As far as I can tell, my ones haven't worn yet, but I'm always keen for preventative maintenance.
Grub screw could work, if there's enough room there to drill and tap a hole from the top, and stop the shaft from being able to move upwards. Might do some investigating over the weekend.

[dave500]

try o rings,it cant hurt.

[dave500]

how about if you remove the two shafts and turn those extraction threads face to face,then using a length of thread and locktight screw them together,then the rocker will have more load to try and rotate as it now has to try and turn both shafts and also the other rocker will have an effect of counter rotation in its action against the pair of joined shafts?the thread needs to be long enough to space the shafts as they were,youll need a good magnet now to remove them again.

[TwoTired]

I understand the idea.  But, the threads in the shafts are for extraction purposes.  If they are joined face to face using those extraction threads, it might be a challenge to get them out later.  Perhaps just buying the later model shafts would accomplish what you are after.

I've done the oring "solution" upon the recommendation of Mike Nixon.  They are stuffed between the end plug and the outer shaft, applying lateral pressure to both.  The theory is that the rockers will turn easily on the shaft and it doesn't take much to force that instead of the whole shaft turning.

I didn't have 10,000 miles on the one with that oring mod (and a brand new old style cover).  And the bike is now in new hands. So, I can't say if practice lives up to theory.

As mentioned, the pressure point oring add on, shouldn't hurt anything.  But, I'm very skeptical that it would have a miracle effect on an already worn valve cover, now out of proper tolerances to hold the shaft in proper geometry.

[dave500]

how about the shafts turned and screwed together and use the oring at the same time?

[Bootsey]

Thanks for the info guys.
I see some of the 500 models also had the longer shafts, yet they are unpinned. From everything I've seen these shafts and rocker arms would be the same as the 550's, is this the case? I saw a set I might grab.

[bryanj]

All the 500 and 550 parts from head gasket upwards are interchangeable mate