arms, rocker arm shafts and bushings/bearings;
valve gear; pushrod tubes; various parts of the cylinder heads.
For BMW Airhead Motorcycles
© Copyright, 2014, R. Fleischer
& rocker end play, ETC!: will be found in
There is more top end information in article 60, section 5 and section 8.
strongly suggest you read them!
Rocker Arm Shafts and Needle Bearings:
This section does not apply to the /5 series, which used bushes, not needle bearings. I treat them separately in this article.
In working with the valve gear, and NOT doing a bearing replacement, I recommend you do NOT disassemble the rocker arm shaft area
unnecessarily.....if pulled far enough out, some tiny roller needles may fall inside...or on the floor. The needles are located at
each end, as a bearing, and the proper amount of them at either
end is just enough so one more will not quite fit, I will get deeper into that later here. The center
area on the shaft is empty.
Rocker shafts will have either a small round aluminum insert (sort of gray in color)...used up to some 1982....or, an OFFSET punch prick, on some 1982...and all later ones. Both markings MUST face UP. The punch prick mark MUST also be outwards...that is, towards the valve cover....except that later shafts are angular drilled, and can be 180° reversed, when needed, to lengthen life. BEST to follow my instructions, and have the markings as above, that way you do not have to worry about whether your shafts are angularly drilled.
Some late 1970's into at least late 1980's needle bearings were faultily made, and an end will fracture and needles will be found in the valve cover(s). See AIRMAIL of September 2004. It is possible that some faulty needle bearings were installed even later. The cage that holds the bearings was faultily-made. It is a metal sleeve that is rolled-over and inwards at the ends...forming a captive area for the needles. The rolling wasn't enough, and the cage was riding on the shaft, breaking at that rolled ends,
rollers came out....note what the rocker block looks like!....there is a split, a gap, and needles can be SPIT OUT that rocker block GAP. Needles are typically found in the valve cover, or in the oil pan.
New bearings is the fix, and you can check them with a rocker shaft to see that the shaft and bearing rolled ends no longer touch. The bearings (you need EIGHT to do all the rockers) are 11-33-1-261-712. They fit all the rockers from the /6 onwards including the 1985+ rockers that are narrower.
Press them in so they are a tad under flush. DO NOT damage them. They've been made with 30 (early) and 31 (now) needle rollers, both are fine....the 31 version has very slightly smaller diameter rollers.
Hints: deburr or relieve faintly, the ends of the rockers so the new bearings install nicely. I think that in a discussion on these a long time ago, Tom Cutter recommended on the LIST that the more rounded end be inserted first....hmmmmm. Notice that MY recommendation has been that if your brand-new rocker needle bearings have a flat end and a rolled end, the flat end is UP. This conflicts with the prior advice on installing them.
You can remove the needles and install them later; use thin grease, even Vaseline (Petroleum Jelly) to help ensure they don't fall out of place. Use of a shaped tool to install the bearing shell is best, and done in an arbor press or in a vice with soft jaws, etc. I've never tried the axle as an installing drift, as some have mentioned, I believe the lip on the axle DOES NOT have enough surface to do a proper job. DO NOT have the bearing proud of the rocker arm end surface. I set them a wee bit below that surface! I have not tried this in a field repair, but see no reason it would not work: Install the bearings using a large bolt and thick large flat washer. Once flush, install a wee bit below flush, using a smaller washer of nearly the same OD as the bearing. Be careful, do things carefully and squarely.
Inspect the rocker shaft for damage.
Adjustment of the rocker end and valve clearance is in article #40, SETVALVES. Be SURE to read it!
There is a pricey update kit, to convert the
rockers assemblies on the 1976
and later bikes to the 1985+ style that use shims.
KIT Part number 11-33-9-057-699. You will also need support
bushings 11-12-1-261-405 if you use the new style rocker arm
assemblies. You could use junked heads from 1985+ to
provide the parts, or swap the heads if in good condition, or
rebuildable, etc. The mentioned kit includes the fin quieting pads: QuietingPads. Don't try
this with the early /5 heads, it won't work. MANY
folks upgrade the earlier bikes to later items in a piecemeal
fashion....such as the later pushrods. The 1985+ models,
and fully kitted early models, adjust their end
clearances by means of shims. These rocker units have a
pressed-in plastic part that helps quiets
noises. The SI bulletin is from May 1986,
and is 11-032-86 (2208). I can supply any individual
part number for you.
NOTE that the 1985+ rocker gear uses a shortened rocker. I think the early eighties rocker gear are better; and NO shimming needed.
a /5 Airhead rocker gear:
First, as noted above the 1985+ rockers, kit, etc., won't fit right out of the box...although they can be made to work. There are TWO types of these early heads. If yours has steel tubes pressed through the fins, next to the spark plug (both sides), these tubes go into the cover area, the rockers are on them. You will need the round spacers that fit the tubes and push against the O-rings, pushing them into the head. Otherwise you will have oil leaks. Use the 1974-1975 needle bearing rockers. There is a later /5 head that the tubes did not show through, and these don't use the O-rings, nor spacers. For these you can use the later rockers and parts up to 1984. The later ones had better heat treated tips. BE SURE to see the photos and notes on the /5 here: http://largiader.com/tech/rockers
the rocker gear on a /5 Airhead motorcycle; and, information on the bushings used on the /5:
NOTE!: /5 models with original valve gear need extra care to align the rockers/shafts/blocks assemblies. There is no locating step machined into the rocker blocks. These parts can all be moved about a fair amount if the rocker hold-down nuts (head nuts) are loosened. Clymer's, Haynes, and even BMW's literature, shows an alignment tool that can be machined-up, but this tool really does NOT do what is promoted. Alignment of the rocker gear is done every now and then during valve adjustment time....by squeezing together the rocker blocks lightly, and then positioning the pushrods in the bores, and keeping an eye on the rocker tips where they contact the valve stem (offset is proper, for valve rotation). In any event, the /5 rockers have a pressed-in bushing, and the bushings wear, as does the shafts.
Here is a trick to quiet those worn rockers!
1. Replace the worn bushings in the rockers if truly bad.
2. If NOT worn terribly badly, simply SWAP the rockers; ...but do NOT move the rocker shafts from
their particular position:
a. move right cylinder exhaust rocker to the left cylinder intake
b. move right cylinder intake to the left cylinder exhaust
c. move left cylinder exhaust to the right cylinder intake
d. move the left cylinder intake to the right cylinder exhaust
NOTE that most /5 cylinder
heads require O-rings at the rocker boss area, where they fit
into the head. Heads requiring these (8 per 2 heads), part
11-12-1-255-167, which became 11-11-1-460-470, and then probably
11-11-1-460-391, can be told from the OUTside by looking for the
tubes, in between the fins.
Rockers, in general:
A good reference for the rockers, which has some photos and discussion, is: http://largiader.com/tech/rockers
head work (valve jobs, dual plugging, all that sort of thing)
that I know of, is done by OAK. Contact
him at: AskOak@aol.com
Oak does excellent work on transmissions, rear drives, ETC.
Oak may have retired, so be sure to send him a message first.
You folks on the WEST coast can use Ted Porter, who I can recommend for ANY type of Airhead work.
On the East Coast, try Tom Cutter at his
Rubber Chicken Racing Garage:
Pushrod tubes, seals, etc....replacement, etc:
Information will be found at: PUSHRODSEALS, ETC
NOTE: I have been told that Seibenrock makes a pushrod tube mandrel...some sort of mandrel is a must when installing new tubes.
the valves, rocker end play, ETC!: will be found in
There is more top end information in article 60 section 5 and section 8.
I strongly suggest you read them!
updated through 06/26/2008
01/26/2008: new, released
10/02/2012: Add QR code; add language button, update Google Ad-Sense code
08/21/2013: Expand information on the rocker bushings/bearings
©Copyright, 2014, R. Fleischer
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