Topic: 75 550 fix typical rocker shaft wear?

[scottly]

There isn't much meat in the cover to tap for a good thread.

I suspected that would be the case, but without having a part to inspect I couldn't tell. Machining the shafts alone would drive up the costs, and welding would blow the budget out the window...

[TwoTired]

Today I checked both type covers thinking I might join in this conversation, but I don't have much to offer. There isn't much meat in the cover to tap for a good thread. There could be a lug welded on first but that would add to the cost.

Really?  I thought it looked ok to me.  Which position(s) did you see an issue?  There is enough meat in the cover to support the shaft.  Where wouldn't a set screw fit?   These covers do wear oddly.  Some of the shaft holes only wear at one end. If the upper surface isn't worn on one end, you would only need a set screw for just the worn end, to restore shaft position and keep from further wear, as the set screw would effectively prevent shaft rotation.

A 5mm tappet adjuster screw might be a good candidate.

You mean as the set screw?  I had envisioned something smaller, like 2 or 3mm.  I think that's enough to hold it place.  Why would that be too small for function?  I agree a 5mm screw is too big for the available metal as cast.

I agree with you Lloyd that marring the shafts would be bad, what about machining a slight flat section for the screw to contact. That would eliminate damage to the shaft.

Agreed.  That is what I proposed in reply #11.  I wonder how big bur would be raised?  That would determine the needed depth of the flat section.

[hellraiserDLX]

Haha I missed the "in" part of that statement. The cat situation is probably the most important thing to the care of well I will keep my eyes open for an updated one and when you are done with house painting we can go from there Maybe. I have aaaaaalllll winter now haha

[bwaller]

I wonder about the smaller screw diameter because they will still need to withstand the rotational force as well. Using four longer shafts would be helpful, but if they were available, latter model covers would be as well!

It certainly is worth trying, I'm watching with interest.

[TwoTired]

I wonder about the smaller screw diameter because they will still need to withstand the rotational force as well.

My reasoning is that Honda didn't anticipate or expect the shafts to rotate in the cover.  I'm not sure why, though.  At any rate if oring pressure at the shaft end is enough to stop shaft rotation (I have my doubts about it's complete effectiveness), certainly a grub screw settled into a flat on the shaft will do the job with far more certainty.

I suppose I should acquire some screws for a future test, which means searching for the most promising tip style.  Any thoughts about tip type for the application?
Flat point
Domed point
Cone point
Cup point
Knurled cup point

A flat point may not scar the shaft enough to require a flat.
easiest to find I suspect will be the cup point  Which can probably be ground flat.

I don't favor the domed or cone tip, as they will certainly require a flat, in order to avoid scarring the rocker bear surface upon latter dissassembly.

A knurled cup point might not need Loctite.  But, I'm not sure where to find these.


If I do make the cover mod, it occurs to me I have no engines that currently need it.  All my operable Cb550s have the new style cover already.  Which is why the old cover mod has been on the back burner for so long.

Are there any volunteers out there to be a test subject?

[hellraiserDLX]

How long would you anticipate turn around time to be?

[Trad]

What would you need sent, just the cover and the rockers? Mine currently has no wear so it might be a good subject.

[TwoTired]

I was out so I bought set screws today.  Couldn't find metric.  So these are 10-32,  $5 for the 16.  I don't think the cover will care.     Would have been nice to keep it all metric, though.  I'll keep my eye out for them in future travels.

If the threat of rain becomes real, it will drive me indoors from house painting and I'll start drilling/milling one of my spare my worn covers.  Then I'll find out how long it will take and whether it's cost effective.  I suspect it will probably take me all day to do the job.  I'm known for accuracy, not speed, ha ha. 
I figure the day will come when there is no choice but to repair.  But, a late model cover is still likely the cheaper route at this time.

As for trade-in, if I need to flat the shafts, probably need to trade those as well.  The rockers should stay matched to the cam, so those won't be part of the trade-in.  The set screws I found are cupped.  We'll see how much they gouge.

I guess painting the cover is negotiable.  I'll need to fix my bead blast cabinet for that task on the one I have, I guess.  Domino projects. 

[RAFster122s]

My '74 is a likely candidate as it has a little over 30-35k. I have been afraid to pull the caps to look as the bike has been a off and on project since I got...mostly off. I have parts for an upgraded performance upgrade with a 605cc Henry Abe I was going to install along with a 650 cam. I want to know the difference in performance. So, I am willing to tear down twice.

How long are you wanting the trial/test?
Tell me more...

I wonder about the smaller screw diameter because they will still need to withstand the rotational force as well.

My reasoning is that Honda didn't anticipate or expect the shafts to rotate in the cover.  I'm not sure why, though.  At any rate if oring pressure at the shaft end is enough to stop shaft rotation (I have my doubts about it's complete effectiveness), certainly a grub screw settled into a flat on the shaft will do the job with far more certainty.

I suppose I should acquire some screws for a future test, which means searching for the most promising tip style.  Any thoughts about tip type for the application?
Flat point
Domed point
Cone point
Cup point
Knurled cup point

A flat point may not scar the shaft enough to require a flat.
easiest to find I suspect will be the cup point  Which can probably be ground flat.

I don't favor the domed or cone tip, as they will certainly require a flat, in order to avoid scarring the rocker bear surface upon latter dissassembly.

A knurled cup point might not need Loctite.  But, I'm not sure where to find these.


If I do make the cover mod, it occurs to me I have no engines that currently need it.  All my operable Cb550s have the new style cover already.  Which is why the old cover mod has been on the back burner for so long.

Are there any volunteers out there to be a test subject?

[RAFster122s]

Yes, I can confirm the shafts have worn holes. Guess I should have scooped up thst 78 cover on ebay a few days ago...
David