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78 R100/7 ...unkown mileage

Was going over FD today to check splines out , clean and regrease I found that had 5 loose rivets in the cup spline...could spin them with my fingers as well as slight rotation in the cup spline itself...WTF! Don't think this is normal.

Since I had a new wheel spine cup riveted on my high mileage bike last year (due to new RD spline rep[lacement) i checked them out to see what shape they were in (after 12,000 kms). Nothing budges on that one. My good buddy did those rivets at his shop with a special jig and peening tool and one MF hammer. I remember watching hin do it and those rivets did not move after he was done, nor do they move now.

Think I'll have John just re-rivet (re-peen) the loose ones and go from there. Maybe try and remove 1 or 2 of loose ones to see if hub holes are elongated (softer aluminum) in that case looks like the nut/bolt procedure. Stay tuned.

So is this just shoddy work from the factory (peening the rivets) or is there something else causing this do you think?

May want to check your rivets at next tire change. I never have in the past but gonna check from now on. I'm not too excited about it just curious as to how it happened.

PS: Tried drilling out loose one just now...pretty hard to do when all they do is spin...wondering if can cut head off with dremel? I'll figure something out.

PPS: So far think mileage is under 50K's. Barrels, heads, rings checked outnicely and FD splines looked only about 20%worn.. just lotsa leaks.

You can drill it off by tilting the drill at an angle.

I woulnd't bother to remove one, just peen it till it is tight again.

Drill at angle that might work if decide to remove a few but after little more examination last night don't think there is the elongation of the hub side holes.

I'm taking the wheel in today to John's shop and get them re-peened. That's his thought too. He's curious to see them. Thinks they were just loose from the factory...no big deal. But I am going to check the other bikes out of curiosity.

Well, back to the leaks....

If they where not factory installed they would probably look it....... all beat to shit. That is often why peened rivets come loose, they get over peened, flatening out too much material and makeing them weak.

Where's Jeff? He's a a pretty good peener.

Garnet wrote:If they where not factory installed they would probably look it....... all beat to shit. That is often why peened rivets come loose, they get over peened, flatening out too much material and makeing them weak.

Where's Jeff? He's a a pretty good peener.

They certainly look "factory peened" nice and uniform...but 5 are loose and 5 are not. I'm not loosing sleep over them but I've never noticed it before (mind you I wasn't looking either). My buddy is going to take a looksee today and probably just re-peen the loose ones, he has a peening head (?) tool he uses and the ones he did on an earlier bike looked nice and uniform and not beat to hell. See if I can get a pic of the process...pretty simple really.

I realize the rivets role here is to provide "shear" strength but if they are loose fitting would that perhaps lead to elongationg the holes in the softer aluminium hub? We'll see later today as we'll take a few out. Only can do 2 cause that's all John has left in the shop for replacement.

Yeah, I heard ME109 swings a pretty mean hammer

If they were all loose I certainly think that would lead to elongating the holes. You would also have probably heard a nice "CLANK" coming from the rear end. With 1/2 loose, I very much doubt the holes would get elongated. If there is slight elongation, the peening should expand the rivets out into the space anyway.

Does anyone (like, Duane, for instance), know if these were originally installed hot, or if they were installed cold?

I don't know because they arrived at the factory already peened in place. At least I think so as I saw shipping boxes of them at the wheel building place. They were packed for shipping, so I assumed that they arrived from some machine shop.

Just like the auto makers here, BMW didn't make much of the motorcycle, they just assembled the parts.

Did someone say peening?
Where's me hammer.....

The exact tool for doming the rivet is the key. Plus a perfect solid support under the rivet head.
With the appropriate tools, peening will dome the rivet to retain it, and also expand the rivet shaft to tighter than a press fit.

That's what me thinks anyhowz, feel free to enlighten.

FWIW, my peened exhaust valve seat was functioning well 9 months
(5,000 k) later and showed no sign imminent failure. It did show signs of other things, however.

ME 109 wrote:Did someone say peening?
Where's me hammer....

FWIW, my peened exhaust valve seat was functioning well 9 months
(5,000 k) later and showed no sign imminent failure. It did show signs of other things, however.

That whole inny outty thing is over rated.

Most likely the original rivets were installed hot so that when they cooled and shrank a few thousands of an inch they provided tremendous clamping force like torquing a bolted joint.