Rocker Arm Shim Wear

[Scotch]

Hi everyone,

This is my first post - I hope I dont screw it up!!

 

First of all, I want to thank Jaap and everyone on this forum. I am a new member and a new owner of a Moto Guzzi Rosso Mandello.

My aim is to "go through" the bike from stem to stern before summer proper and I have used this Forum extensively for info and have embarked on my quest.

 

The most recent project is valve adjustments. I looked up the pinned thread and decided to re-torque the heads while I was at it. (I dont know where this bike has been)

When I pulled apart the rocker arms, I noticed that the "lower" brass shim (the one closest to the ground) has a pretty nasty circular wear pattern where it faces the ?rocker arm support? (the thing that holds the rocker arms and what the rocker arm pins slide through).

 

In other words, from top to bottom

Support with hole for rocker Pin

Stainless Shim

Spring

Brass Shim

Rocker Arm

Brass Shim

Other side of the Support

 

The bottom Brass Shim and the "other side of the support" have pretty intense (nasty) circular wear marks on the faces. The other side of the shim looks good and the other shims look good.

 

This pattern is repeated on BOTH rockers on the right side. I have not destructed the left side yet.

 

Is this normal or should I take off the rocker support and have the face machined where the rocker shim sit and replace the shims?

 

Scott

[Guest ratchethack]

Welcome to the ol' V11 Kerfluffle, Scott! I applaud your effort in doing a "stem to stern" torque 'n threadlock procedure. I find that doing exactly this has considerably enhanced ownership of every bike I've owned (12) by putting me immediately and very tightly into the man-machine bond that I've found to be so very handsomely rewarded with the Guzzi over the years.

 

As far as the shim wear you've described, this would have me curious also -- but not by any means overly concerned. I'd not discovered such a thing when I had my rocker spindles out for head re-torque, and I certainly would have noticed. It could be that a machining chip wound up trapped in there, and that you freed it when you unstacked the rocker spindle. Can you tell by looking at the rocker spindle "support" that there's a burr or other left-over casting artifact that needs filing or perhaps just de-burring with the tang of a bastard file? You should be able to feel it if you can't see it. If you do find such a thing, I would take care of any roughness on the casting, flip the shim over, and not give it another thought, since there's not much of any axial thrust load on the shims. But that's just me.

 

Amongst other "attributes" of these hand-made anachronisms born at the famous Guzzi works at the shore of Lake Como, the Luigi's have been known to "personalize" these bikes for us in various ways. "Grappa enhanced assemblies" have been numerously postulated. Dropping a ravioli or two down a pushrod tunnel, f'er example. Raviolis ain't nearly as tasty when they're found agianst the sump screen a few years later here in the US. . . (just kiddin')

 

Good luck.

 

Don't take the usual "Winter of our discontent" hereabouts too seriously lately, my friend. The natives are a mite peckish lately with cabin fever, and Spring is somewhere around the next coupla bends. . .

 

FWIW, just my opinion, but I b'lieve you've selected a true classic V11, one highly sought after by many "in the know" for its "short frame" geometry. My Sport came with the same 25 degree rake as your RM. (It's the bee's knees of V11 handling.)

[pete roper]

Is there plenty of oil in the top end? If it looks a bit dry check that the rocker spindle support bolts haven't been replaced with longer ones. If longer than standard bolts are used, (I think that the stock ones are about 15mm long but I'd have to check to be sure.) they will block off the oil feeds through the rocker spindles and the whole top end runs dry, with predictable results.

 

Pete

[Greg Field]

Sounds pretty normal. That said, check for burrs on the rocker or a bushing that isn't fully pressed home.

[Scotch]

Thanks Guys

Thanks Ratchet - after getting rid of the "hog" and taking a hiatus from riding for a while, my friend found this bike and it is just what I was looking for, even though I didnt' know I was looking.

I like to turn a few wrenches (keeps me out of trouble) and I wanted to buy something whose market value wouldnt plummet like the recent stock market as soon as I got it.

I think this bike fits the bill very nicely.

(its sexy too)

 

Since you last heard from me I have completed the "top end" work and the bike is back together although not "tested" yet.

 

The curious thing about this situation is that ALL 4 bottom shims are scored exactly the same way on one surface only.

 

If you can imageine a "bulls eye" target - there are concentric score line circles just like the brass shim has been dry spun against the aluminum casing. The casing is scored also, so much that the washer and the case dont want to be seperated. I had to pry all four off.

 

Having said that, the other surface (facing the rocker) and the rest of the shims and rockers look PERFECT, so Ratchet, I didnt want to turn the shim over exposing the bad side to the rocker arm. Since it didnt look like the spacer is going to be moving, I reassembled the head just like it came off, cleaned and coated everything with assembly lube, and set the valves to 6 and 8. They were way tighter than than before.

 

I figure before too much longer, I may pull them back apart and see if there are any changes.

 

All the bolts look stock and they are the same length - doesnt look like they have been messed with. The bike only has 7000 miles on it so how many times could it have been messed with?

 

Thanks again, Scott

 

PS - Pete, just noticed your name on the post - I'll have the Roper plate in hand and that is my project the week after next!

[Guest ratchethack]

The curious thing about this situation is that ALL 4 bottom shims are scored exactly the same way on one surface only.

 

If you can imageine a "bulls eye" target - there are concentric score line circles just like the brass shim has been dry spun against the aluminum casing. The casing is scored also, so much that the washer and the case dont want to be seperated. I had to pry all four off.

Scott, I don't mean to annoy you with worry, but you didn't mention finding any burrs on castings or bushings. Nor did I understand first pass that the scoring is on all 4 bottom shims. This has me a little concerned about oil getting to the rocker spindles as Pete noted. You might check the bolt depth against the depth of the galleries as Pete indicated. An easy check for top-end oil pressure is to run the motor at idle with rocker covers off. It won't be spraying out like a fire hose, you'll not lose much oil, and IMHO it'd be worth the effort for a peace-of-mind look-see, just to eliminate the possibility of a top-end oil line blockage.

 

Just a thought.

[Scotch]

Well noted, Ratchet.

Yes, the first time I posted I was looking at one, stopped what I was doing and made the post, then Sunday came along and I got into the others.

All four look identical, I noticed no burrs, but the casing is scored matching the shims as they obviously were rubbing. I'll do some more investigating into this before hopping on and riding.

I have to say, though, there was oil all up in there, dripping on my garage floor, even though this bike has not been ridden in, well I dont know how long. I bought it from an estate from people who dont ride.

 

I am actually going to start a new thread asking for renovation advice. This bike is a teeny way into what I hope is a thorough going through and I want to make sure I dont miss anything.

 

Since I have a "ways to go", I'll definitely revisit this issue and perhaps take some kind of action.

[Scotch]

I decided to pull one apart and take some photos to share with any of you who are interested.

Notice the circular abraison pattern on the rocker carrier and the matching face of the brass shim.

This is only on the one face of the shim and carrier mating surface.

It ONLY appears on the lower shim and it appears on ALL FOUR of them.

The rest of the rocker parts, shims and surfaces look good.

Top Shim on the left, Bottom (worn) Shim on the right.

 

Scott

[Guest ratchethack]

Scott, that's exactly wot I'd imagined from your description. My take is still that this is not normal, but not necessarily all that alarming, unless you have an oil delivery problem to the rocker spindles, as mentioned previously, in which case it'd be a first priority, critical thing. If it were me, it's certainly the kind of thing that'd be annoying enough to want to get to the bottom of. I can't recall if you'd verified the proper sequence of the rocker spindle "stack"?? I know from previous posts on this that it isn't all that unusual to find a "meddled-with" rocker spindle stacked-up out o' sequence. Just thinking out loud, could a PO/mechanic have re-installed something in incorrect order, where you may have a spring incorrectly putting axial loads on the shims?

 

Maybe Greg or Pete have seen this one before??

[Scotch]

I can't recall if you'd verified the proper sequence of the rocker spindle "stack"?? I know from previous posts on this that it isn't all that unusual to find a "meddled-with" rocker spindle stacked-up out o' sequence. Just thinking out loud, could a PO/mechanic have re-installed something in incorrect order, where you may have a spring incorrectly putting axial loads on the shims?

 

Maybe Greg or Pete have seen this one before??

 

I did say before, but the stack from Top to Bottom is

Steel Shim

Spring

Brass Shim

Rocker

Brass Shim

 

I actually found 1 out of 4 that the steel and brass shim were mixed up, but only 1 and it didnt seem to wear any differently from the others.

 

Scott

[Guest ratchethack]

Scott, I know you'd listed the sequence you found yours in, in your opening post, but I can't recall from memory what's correct, and I didn't know if you'd yet been able to verify the correct sequqence since then with a credible source. I just took a couple o' passes thru the Guzzi Shop manual and couldn't find the correct sequence noted anywhere. You note above that you were able to verify that 1 out of 4 steel and brass shims were mixed up. I'd say this is about as good an indication you're apt to find that the probability is pretty good that it's still out o' sequence now, and this is the source of the unusual wear problem, as I indicated above. Maybe someone with their rocker covers off will chime in here with the correct "stack order" if Pete and Greg don't reply first.

 

Got to hand it to you for noticing something that many wouldn't have noticed a-tall, and kudo's also for the persistence to track it down and correct it!

[Scotch]

I didn't know if you'd yet been able to verify the correct sequqence since then with a credible source.

 

Guzziology gives the order. Round heads dont have the bottom brass shim (the one I have problems with) and square heads do. Also the round heads have the spring next to the rocker while the square heads have the bronze washer next to the rocker then the spring.

 

Steel Shim

Spring

Bronze Shim

Rocker

Bronze Shim

Is the order he gives for Square heads.

He states in his book that the order is not really clearly specified anywhere else.

 

Again, I put it together, rode it for 5 minutes, let the bike sit for several days and took them apart today. There is oil oozing from the pores in the rocker assembly and everywere up top.

I could not see any particular way that bottom shim gets any oil except by plain old migration. The oil races seem to be lubricating the pivot on the rocker arms. Unless someone convinces me otherwise, I think I am going to put this one to bed for now...If that wear were up next to the spring or rocker arm itself, I would be more worried.

 

Scott

[Guest ratchethack]

Ausgezeichnet!

[raz]

Maybe good old Luigi ran out of assembly lube and decided to use vinegar instead? If the shim and it's mating surface was flat enough it could take some time before enough oil got in there.

 

Anyway if you're worried I guess four shims will cost almost nothing and you could probably sand down the supports in no time. Then YOU use assembly lube when putting it together. I wouldn't stop riding while waiting for parts though.

 

Note: I am just a couple of years ahead of you, so sanding the supports is an idea and not a professional advice :!:

[pete roper]

Flip the worn one over and re-install. I've seen all sorts of mixed up shims on rocker gear but I've yet to see one stop working because of it

 

Keep an eye on it, blow the rocker spidles out with compressed air before re-installation.

 

Go ride.

 

Pete