Rocker cover center stud

The center stud from the rocker cover on my 1982 R100/RS fell out while on my last ride of the season. I was told it was stripped from PO. I'm going to Helicoil the repair and I was wondering if I should lock tite both he coil and the stud?

Any suggestions?

Won't hurt...the most often stripped hole on the entire bike.

Just make sure you have the stud depth right...doesn't need to go all the way through the head and the nut needs some threads to catch.

ive never loc tited a hili coil, I guess a person could.
my last bike, the p/o had prob stripped and put back in with redloctite. or thats what he told me, I never pulled it out to find out

Lots of mechanics seem to like Time-Serts over helicoils these days.
http://www.timesert.com/html/mtrcsert.html

Wish I had known about Time-Serts

I had wallowed, stripped and bent center stand bolt holes and wish I had found out about those Time-Serts before I fixed them. I mad a tool to straighten them without motor removal and then drilled and Heli-Coiled them, I used J-B Weld on the Heli-Coils inserts, hope the hold as good as they have so far

I had one strip on a /6. I skipped the helicoil/timesert step and put the new one in with JB Weld. It held for years and was on bike when I sold it.

Another possibility, maybe a short term solution if you weren't taking the head off, is to find the metric stud...I think 70-75mm long...and drop a nut in the small cavity near the spark plug. Probably have to grind the flats a little to get the nut to fit. Loctite the nut on...be sure enough threads but not too much stick through to use the standard acorn to tighten...just enough.

Happy Wanderer said:

Lots of mechanics seem to like Time-Serts over helicoils these days.
http://www.timesert.com/html/mtrcsert.html

Click to expand...

I also have a wallowed out center stud bolt hole and like the Time-Serts option. I assume if the bolt is 8 x 70mm I need the 8 mm Time-Serts kit? or do you go one size up?

The kit I think I need is TS18101 - M8X1.0X11.7 from https://www.belmetric.com/ts1810-m8x10-kit-p-1505.html?cPath=217_218_231

20774 said:

Another possibility, maybe a short term solution if you weren't taking the head off, is to find the metric stud...I think 70-75mm long...and drop a nut in the small cavity near the spark plug. Probably have to grind the flats a little to get the nut to fit. Loctite the nut on...be sure enough threads but not too much stick through to use the standard acorn to tighten...just enough.

Click to expand...

Thats what I did, as I remember it is 72mm long and I used a nut that was 1/2 the width of a normal one.

While you're at it, acquire a NEW stud from your dealer.

Reason for stripping in many cases is that for a while BMW factory-fitted too-short studs.

Reason for stripping in many cases is that for a while BMW factory-fitted too-short studs.

Click to expand...

Meaning that the thread-length (engaged in the head) was too short?

76914 said:

I also have a wallowed out center stud bolt hole and like the Time-Serts option. I assume if the bolt is 8 x 70mm I need the 8 mm Time-Serts kit? or do you go one size up?

The kit I think I need is TS18101 - M8X1.0X11.7 from https://www.belmetric.com/ts1810-m8x10-kit-p-1505.html?cPath=217_218_231

Click to expand...

Pretty sure the one you want is for the same size the stripped bolt was. You can check with the vendor to be sure but the idea here is to end up with the same bolt you started with into threads that are now restored with a steel insert.

Aluminum threads where bolts are removed frequently like the valve covers don't hold up as well as steel does. I think the center bolt and the two 10mm nuts on the back of the valve covers are often victims of over use and over tightening.

lkchris said:

While you're at it, acquire a NEW stud from your dealer.

Reason for stripping in many cases is that for a while BMW factory-fitted too-short studs.

Click to expand...

I can attest to this. I just pulled one of the studs out of my heads as I returned from a trip and noticed the 13mm cap nut had fallen off. Once I pulled it I realized the threads were pretty stripped, mind you I don't overtighten my nuts because I was aware of this problem, and I'm not really sure how this happened.

Looked into the head and there were still some good usable threads so I figured I'd go get an 80mm stud and a nut so I could go through the head and secure the stud with a nut on both ends as others have suggested. Also went to the dealer and bought another stud in case I wanted to go the helicoil route. The part for my R90/6 indicates 70mm stud length according to MaxBMW and this is what I received from my local dealer. Before putting in the 80mm stud and nut I purchased I just threaded in the new 70mm one I got from the dealer and I guess there were enough good threads that my problems are over (for now), no need for helicoil or the 80mm stud I bought.

I then went to the discarded, stripped stud and measured it to find it was 66mm in length meaning, I suppose, I have at least 4mm of threads in the head that weren't being use. Now BMW specifies 70mm length according to their microfiche and I'm pretty positive that stud is original to the bike considering the apparent age and wear of everything else on it, so BMW must have fitted shorter studs as Kent said.

I couldn't say how this would strip out anything being shorter, but this is my experience. Maybe you can luck out like I did and avoid helicoils/timeserts just by going with a new stud, but then again, we'll see how long my repair holds up before I have to use that 80mm stud I bought

I have this problem, perhaps a worse version of it. Not only did the stud fall out, but the helicoil "slinkied" itsedf right out when I was trying to see what the depth was. Stud, helicoil out, now what?

Stud, helicoil out, now what?

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An Over Size, or TwinSert HeliCoil might do the trick ... if you can find a mechanic/machinist that has a kit.

http://www.helicoil.com.sg/HeliCoil-Oversize-Twinserts.htm

PDF > http://www.emhartamericas.com/sites...ds/helicoil-oversize-and-twinsert-inserts.pdf

or... JB WELD (with the likelihood that it won't last too long).

Your local BMW dealer should have a Big-Sert kit. Oversized OD Timeserts with standard size ID.

The Big-Serts come in different lengths and sizes. Use them for pulled engine studs that have been helicoiled before and for the head center stud in situations like yours.

The Big-Sert kit retails for around $700 and the Big-Serts sleeves run about $4-5 each. Ask to borrow the kit if you have a good relationship with the dealer.

These things will never pull unless you use a breaker bar on the nut.

The other option is to get the 80mm stud from the dealer and use JB Weld and a backup nut behind.