Topic: 75 550 fix typical rocker shaft wear?

[hellraiserDLX]

I know this can be fixed with the updated valve cover/rockerbox assembly , but I can't seem to come across one. I think I saw a write up on how to fix the old ones with set screws, but I can't find it anymore with the search.  If anyone could help out with this topic my bike and my ears would be very appreciative!

[TwoTired]

I suggested this a a possible fix.  But, I haven't had the time to implement it.
I know Scottly asked for a cover to experiment with.  But, I haven't heard whether he got one to try out.

I do have a spare worn cover to try it on.  And it seems straight forward enough to implement.  I just need the time to try it.
 The valve spring pressure wears the shaft holes oblong and upward, leaving the bottom half of the shaft bore intact.  There are eight shafts in the cover which need each end of each shaft forced down to the bottom of the shaft bores.   The idea involves drilling in from the top of the cover into the shaft bore, then tapping the hole for a set screw which would then be installed after the rockers and the shafts were in place in the cover.  I guess 16 holes and screws would be needed for completeness.  But, it might also be done to only those positions where the wear is excessive.  Personally, I'd want to at least stop each shaft from turning even if they currently had good bore positions, and one set screw per shaft would do that.  However, to insure that the shaft geometry was maintained, worn shaft holes would need two set screws per shaft. 
I have both a drill press and a Drill/mill/ lathe which seem handy for the project.  I suppose with sufficient care, even a hand drill could be used, though.  Prowess dependent.  I'd select Loctite 2422  to seal the setscrews and keep them from loosening, as well as withstand the heated environment.

I'm supposed to be prepping the house exterior for paint and then painting for upcoming sale.  But, that isn't very exciting or interesting.

[hellraiserDLX]

I knew I saw something like this before. Thank you for that. I guess ill just have to pull it apart to see where the screws would be able to be put in place. I have a few buddys with nice machines to use, but the actual placement of the set screws is my only delema. It would be a lot easier if I jad the cover sitting in front of me I suppose haha.

Don't feel so bad about painting the house.  I clean cars for a living hahaha

[754]

You will have to set the bores up so they are in a perfect straight line, then clock in the unworn part, the bore out or use and endmill in a fairly rigid spindle,
 If you offset the bore you can get away with a possible slight ratio change or adjustment screw problem.  How far apart are the bores ? And is there a straight shot at them
?

[Duanob]

TT you might have a side bidness for fixing the older style covers. 

On the subject of the OP can't find one there are usually quite  few of them on ebay. You need to know how to ID them. Older style on top two pics, newer style bottom two. There are four keeper studs inside the camchain cover.

[Trad]

I just put an o ring between the cover end caps and the shaft ends. It sandwiches the shafts and prevents them from spinning. I have zero rocker wear on my old style cover. Just a thought. If yours are already worn this will only prevent future wear not fix what you already have going on.

[hellraiserDLX]

I have been trolling the bay for awhile in search of the new style but with no success. Thanks for the pics though. The rattle ia bad enough by cylinder one that I don't think I even need to look at the wear physically to know that the o ring wrong work on that one.  I think ill just keep looking for an updated version and tinker with the old one when I swap em. Thanks guys!

[Hasenkopf]

you could always bore the shaft and pressueize the hollow shaft with oil and an external line.....

[wally550k0]

I found the kit at http://www.hondarestoration.com but I think I got his last one.  Try CMS.

[scottly]

I suggested this a a possible fix.  But, I haven't had the time to implement it.
I know Scottly asked for a cover to experiment with.  But, I haven't heard whether he got one to try out.

No, I never did, but after seeing Duanob's pics, I have a much better idea of what would be involved. The hole locations would have to be mapped from the bottom side of the cover, using the dowel holes as the reference points, then flipped over for the machine work. A flat spot would need to be milled for each hole before drilling, as a drill will drift when feeding into an angled surface. This is a mill job. 

[TwoTired]

I had some time to take some pics.

The first shows a wooden dowel which is now inserted in the shaft bores.
I've taped the end cap and it's dowels onto the end to register where the end of the shafts will be after assembly.
I also taped the shafts onto the top of the cover to register where the set screws should contact where the rocker bearing surface is not.

The second pic shows the coarse location where the set screw holes would be drilled and tapped marked in red grease pencil.

The set screws should push the shaft down onto the bore "floor" which doesn't have the worn surface to upset rocker geometry.

[TwoTired]

A mill would be great for this job.  But, you could chuck the end mill in a drill press to flat the surface, and then drill into the flat.

I can't imagine the set screw locations are super critical.  But, the setscrew must hit the highest point on the shaft somewhere along the screw end width.

I thought about the set screw gouge later in life when dissassembly is required.  Maybe there should be a flat ground on the shaft set screw points, so the gouge cant score the rocker inner bearing surface during extraction.

[scottly]

I also considered the gouge left by the set-screws; this shouldn't be an issue with bores so worn that they need this fix? Most drill presses have a lot of slop in the spindle, and don't make very good mills. My concern is how much "meat" there is to support the load on the screw threads in the cover where the holes go.

[Duanob]

Not many available currently. I guess timing is everything. There were lots earlier this past summer. I found one but it seems pricey for the condition. However it does have free shipping. If it doesn't sell maybe you can make the seller an offer.

http://www.ebay.com/itm/1976-HONDA-CB550-CB-550-VALVE-COVER-HEAD-ENGINE-MOTOR-/390343513170?pt=Motorcycles_Parts_Accessories&hash=item5ae2495452&vxp=mtr

[TwoTired]

I also considered the gouge left by the set-screws; this shouldn't be an issue with bores so worn that they need this fix?

Not worried about the shafts scoring the cover bores.  Rather sliding the rockers off the shafts and scoring the bushing in the rocker.

[hellraiserDLX]

 This sounds like I should send mine to twotired when he seals the deal

[TwoTired]

you could always bore the shaft and pressueize the hollow shaft with oil and an external line.....

I don't believe it is an oiling issue.  The bores on the failed units I have seen were always well oiled, flooded in fact.  The rockers are supposed to rotate on the shafts.  Shafts are steel and the rockers are bushed, I think.  Sometimes the rockers are tight enough on the shaft that the shafts turn in the soft aluminum along with the rocker movement.  Even if oiled the aluminum is sacrificial when rubbed on by steel.

I'm not convinced that the orings against the end shafts are an effective cure.  I don't think they hurt.  But, there hasn't been evidence that it is a long term cure.
The worst part about the wear is that it is not even or equal at each end of each shaft.  This tilts the follower face at the cam lobe interface, leading to galled cam lobe and follower faces.  O rings certainly won't cure this uneven wear geometry issue.

[scottly]

I also considered the gouge left by the set-screws; this shouldn't be an issue with bores so worn that they need this fix?

Not worried about the shafts scoring the cover bores.  Rather sliding the rockers off the shafts and scoring the bushing in the rocker.

Good point. Are the rockers bushed?

[bwaller]

No.

[scottly]

Thanks Brent. I didn't think they were, but wanted confirmation from a 550 expert.

[TwoTired]

I also considered the gouge left by the set-screws; this shouldn't be an issue with bores so worn that they need this fix?

Not worried about the shafts scoring the cover bores.  Rather sliding the rockers off the shafts and scoring the bushing in the rocker.

Good point. Are the rockers bushed?

I couldn't remember if they were bushed for this engine or not.  I checked my spares and it doesn't appear so.  But, it is irrelevant to the issue.  I still don't want the rocker bearing surface to be scored by a bur on the rocker shaft as it slides off the shaft.

[TwoTired]

This sounds like I should send mine to twotired when he seals the deal

I expect Scottly is way more interested in getting your business than I am. 

If I do it, it will likely be a trade in affair. 

[hellraiserDLX]

This sounds like I should send mine to twotired when he seals the deal

I expect Scottly is way more interested in getting your business than I am. 

If I do it, it will likely be a trade in affair.

Well I'm not sure what I woukd have for trade if it came down to it but what would you be looking for if that were the case?

[TwoTired]

This sounds like I should send mine to twotired when he seals the deal

I expect Scottly is way more interested in getting your business than I am. 

If I do it, it will likely be a trade in affair.

Well I'm not sure what I woukd have for trade if it came down to it but what would you be looking for if that were the case?

"Trade in" 
You send me yours and if in repairable/ serviceable condition, I send you one of mine with modifications already done to it.
That way, if I screw up a mod, it was on my cover, not a customer's.

I'll be the first to admit, I'm no businessman.  I've never been able to make a business that's profitable, or even self sustaining, for that matter.  I think I'm still a pretty good engineer/craftsman, though.  I just don't have a businessman skill set.

Anyway, I'd rather do trade-in than a "core charge" model of business.
I can't say when I'll get time to finalize the repairs/mods, though.  House painting prep is sucking most of my work time these days (along with feral cat control  ).  And I just can't do the 12 hour works days anymore.  Aging sucks.

[bwaller]

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