Valve cover center stud stripped/fixed

[montmil]

Three airheads out of five bikes on last Sunday morning's ride so naturally the talk was about ...airheads.

R90 buddy mentioned he had stripped threads in the cylinder head for the valve cover center stud. R100 guy said he had just fixed his stripped cover stud last week with a heli-coil insert. Hum... Me, too, with same issue on right side cylinder on my R65. What is this? An epidemic?

I had discovered my issue after re-torquing cylinder heads, setting valve lash and fitting new valve cover gaskets. Manual said 16 ft lbs to tighten... if I remember correctly. Anyway, the stud was turning around 10 lbs. PO had been a bit too aggressive with the socket wrench as evidenced by aluminum in the stud threads.

Picked up a heli-coil kit at AutoZone. OEM brand made in Oz and the included tap made in S.Korea. Three heli-coils included. Well, at least it's not from China. 8 x 1.25mm is what you need for the center stud fix.

Hooked up with R90 man this evening and it took just over an hour to repair both bikes. He has a cool air lift service table for his bikes. Two Sam Adams included in the job.

Drill out the stud bore with 21/64 bit. Thread the hole with the included tap. Use the neat heli-coil insert tool to wind in and then snap off the coil's installation tang. We used some red LockTite to aid in keeping the insert secure. Put the stud back where it belongs and button up the valve cover.

I went home and grilled a couple steaks for supper.

[MrRiden]

Thats it! I'm moving to Texas! seems the r65 people there have all the luck / fun!
rich
http://www.youtube.com/watch?v=scjb_f95diA

[Justin B.]

When your next one strips, try running the helicoil tap in without drilling.  I have yet to need to drill any of mine, guess the old stud yanked out enough Al for the right fit!

[montmil]

When your next one strips, try running the helicoil tap in without drilling.  I have yet to need to drill any of mine, guess the old stud yanked out enough Al for the right fit!

I had read that... about not drilling. But what the hey, we got both putt-putts fixed without any angst.

[Justin B.]

I'm lazy...

[montmil]

I'm lazy...

Too hot not to be. The R90 and my R65 were in an air-conditioned work shop. So harsh  

[BooG]

I need to do this fix. If you do need to drill, do you just do it by hand? I was gonna pull off the cover and make a jig.

[montmil]

I need to do this fix. If you do need to drill, do you just do it by hand? I was gonna pull off the cover and make a jig.

No jig needed. We used a 21/64" bit in a cordless drill. I looked down on the drill and visually aligned it "left to right" while Bobby "O" -the R90 cat- watched from the side and corrected any "up-down" positioning required before I pulled the trigger. The existing stud hole pretty much keeps everyone headed in the same direction.

Or you could skip the drill bit and simply run the tap in as was the suggestion from the official BMW "Lazy Man Justin" School of Beemer Thought... Ahummm

Either way.

Do not be alarmed when the drill bit runs all the way through the head. Peek into the empty stud hole and you'll see that it does indeed pass through the head to ambient air on the other side. My drilling instructions to Bobby "O" were to, "Stop drilling when you hit the top of your piston."  

This is a simple yet gratifying project. It was simple for us and it'll be the same for you, Booger.

Let us know if you find an AutoZone in London Town.

[Justin B.]

The only thing I can think to add is to load up your tap with grease.  The chips from the tapping process will sticik to the grease and you'll run less of a chance of getting swarf where it doesn't belong.

[montmil]

The only thing I can think to add is to load up your tap with grease.  The chips from the tapping process will sticik to the grease and you'll run less of a chance of getting swarf where it doesn't belong.

That's always a good idea. We used an assortment of materials to keep ol' Swarf at bay.

[Rob Valdez 79 R65]

I stripped one of mine a long time ago.  It was fixed by my dealer at the time.

A few years ago I went for a day ride, and when I stopped half-way, I saw the stud laying in the opening.  The acorn nut long gone.  I threw the stud in my saddlebag and promptly forgot about it.

I sent my heads off for refurbishment a couple of years ago, and the mechanic, Bob Grauer heli-coiled one of them (gratis!), I don't remember which one.

I have never bothered to put in studs or acorn nuts.  The two 10mm fasteners do a good job of holding the cover on with no oil leakage.  I have even considered just gluing on the acorn nuts!

One trick I have heard some folks talk of is to thread the stud in far enough that you get some threads coming through the "inside", and put a regular (NOT nylock!) nut on that end.


Oh, and this does not go into the combustion chamber (unless you REALLY screw up!) so you don't have to worry too much about swarf except to keep it out of the threaded area.