92' R100 rocker shims?

[iansnook]

have some serious ticking! and need to shim the rockers on my 92' R100GS. did some searching w little results. The parts are sorta still avail from BMW but @ 4-9 bucks a whack for precision washer seems exorbitant! Hoping there's someone in the know out there that could tell me the ID and OD of the shims needed for taking the lateral play out of the rocker arms on later model airheads. Saw some threads on buying shims from McMaster Carr etc but could not find anything on the dimensions needed. I've measured the width needed but didn't want to take the rocker assembly off just measure and do it twice if I could avoid it by asking here.

Thanks in advance for any help. Ian S

 

[83014]

Check with Anton.
http://www.largiader.com/tech/rockers/#8

Doug

 

[20774]

I think the thicknesses are listed here:

https://www.realoem.com/bmw/enUS/showparts?id=0488-USA-01-1992-47E2-BMW-R_100_GS&diagId=11_1792

 

[iansnook]

Thanks looked an Antons site but nowhere can I find the inner and outer dimensions. I would like to order several widths for future and other airheads I have. Shims can be found on the BMW fishe & the parts can be had at capital cycle / Max etc but thier $9.00 ea.

Ian

 

[stevenrankin]

Shims?

Do you mind me asking but are you having problems other than a ticking noise? Why do you feel the need to shim the rockers? I have a lot of miles and years on my airhead and never felt the need to add shims?

All the airheads I have ridden or worked on or seen at my friend's shop tick at idle, Three of my past airhead mechanics have never shimmed rockers. Do you reed the added work for no gain in reliability or performance? St.

 

[RPGR90s]

I owned a '93 R100RT from new and I thought that the rocker assemblies were self centering??

I have to adjust the rocker clearance on my R90s when re-torquing the heads, but every time I re-torqued the heads on the R100, the up/down movement of the rockers was maybe .003" max.

I was told and assumed they were self-centering.

 

[stevenrankin]

Self

I believe you are correct the newer airheads such as my 84 are self centering, that is why I have never had to add shims. I should have written that in my first post.

Proper adjustment of the older rockers also means shims are not needed. If you need shims, you have other problems that need to be addressed. St.

 

[iansnook]

So I have loud ticking one side (exhaust) and relatively quiet on the other. I took off valve covers and measured end play. each was different and all needed to be shimmed. No coincidence that the loudest valve was the same one that has the most end play at around .006"

Way I understand it is that the rockers are to be shimmed to a tolerance that provides no more than an oil film while still allowing free and full movement of the rocker arm when adjuster is fully backed off. Snowbum's site is very clear that about 90% of valve noise complaints are the rocker arm sliding on the shaft and contacting the rocker block assy, not the valve clearance or normal noise. This only pertains to I believe post 84' when the blocks were set into immovable pockets in the head and no longer adjustable by force or squeezing toegether. Also, the way the rocker assy on the BMW operates is the rocker contact is eccentric in order to rotate the valve slightly during actuation and therefore pushes the rocker arm laterally, hence the noisy contact with he rocker block. Lastly this assembly uses a plastic shim as part of the assembly which also wears and therefore the need to be shimmed / adjusted every so often. Aton is clear about this too but for some strange reason no-one seems to know or have listed the diameter of these shims. only that they are available easily and commercially for cheap. I have yet to find a dealer that has them and on line what can be had is 9.00 ea. for a shim that can be had for pennies. Lastly the lateral movement of the rocker does contribute to wear. of the valve stem, the rocker, the rocker bearings and the shaft. that rocker is slamming against the rocker block on every actuation causing unnecessary wear and annoying noise.

Ian

 

[stevenrankin]

Ah

Thank you for the information Ian, disregard any advice I gave, I stand corrected. I suppose it would help to read Snowbum's site from time to time. St.

 

[iansnook]

No Worries Steven. I appreciate the reply none the less. Surprised though, still no takers on this one?? Looks like I will have to disassemble the necessary parts and report back the findings should others be interested, although, looks like perhaps not!

Ian

 

[lkchris]

Shimming of the rocker arms was introduced to meet ever tightening German noise regulations. There are rubber buttons in the fins of these models as well.