Rocker shaft endplay - is .002" ok

[Barry]

The weathers not great and I'm bored so being curious about rocker shaft end play I've removed the valve covers and measured it for the first time.

There is only a little movement perhaps a tad more than just the oil film. A .0015" feeler slides in a .002" is tight and will not go all the way. A .003" feeler will not begin to enter the gap.

All gaps are remarkably similar between .0015 and .002"

Maybe I could close them by .001" but I'm inclined to leave well alone and anyway I have just discovered that I don't have a 3/8  drive 15mm socket that fits my torque wrench so that settles it for now.

What else can I do - I know I'll put a liitle extra oil in the forks and see if it helps with the ocassional clonk. I may even get to try it out if the rain stops.

[steve_wicks]

If they aint noisy ... leave them as I'm convinced you need to disturb head bolts to do the float!

Some people say you don't need to, but then how do you move then to adjust the float so it stays as you set it.

[nhmaf]

I would say that if you're  under .003" then you should be fine.  BMW doesn't even make any shims that can reliably get you less than that in any case.  I would call that good unless things are still very noisy, but I wouldn't expect that small amount to cause much noise.  If you are up around .006" or so you would DEFINITELY hear a difference.

Time to ride !!

[Darwin_R65]

Leave it alone unless it's noisy?
We are talking about a BMW aren't we?

John

[Bob_Roller]

.20mm is the thinnest shim you can get, that works out to be just a bit under .008 in.

[Andy-Gadget]

.20mm is the thinnest shim you can get, that works out to be just a bit under .008 in.

0.02mm = 0.0008"

All you need to convert is one number, 25.4, this is millimeters per inch, works either way, simple.
0.02mm / 25.4 = 0.0007874..."

0.0008" X 25.4 = 0.02032mm.

To restart the "loosen or not to looses" debate (argument), the only thing locating the pillow blocks sideways is the frictional force generated by the tension on the head studs, they aren't spiggoted at all.
Loosening the head studs allows the pillow blocks to be easily moved, but the pillow blocks can also be moved when tight, just needs more force, hence the socket and hammer.

I am of the opinion that one reason for stripping head studs is the re-torqueing at valve adjustment, I never have, and my R100RS is 375000 k's old, and I have never done a head gasket.
Hence my socket and hammer adjustment of end float, just my opinion of course.

[Bob_Roller]

The thinnest shim is .20 mm, not .02mm .

[Andy-Gadget]

The thinnest shim is .20 mm, not .02mm .

I see it all now, you are referring to the later BMW shims.

I read your post and thought feeler gauge, sorry.

I have never tried to fit them to any early model bikes, as I can get them good enough as they are.
Sorry for the confusion causing answer.

The shim system works, I think, by making the pillow blocks move as far apart as they can, so they can't increase the clearance, then shimming the rockers to correct end float for this situation.
I can understand that this will work, but consider it to be "dumbing down" by making it a "factory" adjustment.

Pedantic bastard aren't I.

[Barry]

Thanks for all the feedback.

My valves are fairly quiet.  I suppose what I wanted to know was at what clearance do they become noisy so it was interesting to hear that .006" really would be noisy.  

I was also confused why the post 85 shimmed rockers have a quoted clearance of .03mm to .07mm (approx. .0012"  to .0028") and the earlier unshimmed rockers should have zero or oil film clearance. I can't see why there should be a difference so as I seem to be in the right ball park I think I'll leave well alone.

Something good did come of my desire to tinker . A little extra fork oil seems to have made a difference. I'll follow this up on the noisy fork thread.

[Semper Gumby]

.002" is the number I have seen in my BMW Factory repair manual so I would say that you have got it spot on!

TTFN,

[Landlubber]

Yes sounds OK leave it alone, the most important thing is that there IS clearence, I do mine so the gap squished oil when the rockers are moving that way you know there is clearence, but not much.