So I get the valves all sorted and the rings done and now...

[JimmyR]

I'm bolting down the cam shafts and one of the things that holds down the exhaust cam has a threaded bolt. Great. I am certain that I didn't thread it. It never got close to being tight.

Oh well. Back to the machinist I guess to get a new thread insert. Just as soon as I do one thing another pops up to slow me down. Is there anything I need to know/watch out for when I get the new thread in the head? The guys I am taking it to are very knowledgeable and I actually trust them (!) but I like to know as much as possible before spending money on things.

[chef1366]

I heli-coil those cam cap threads all the time.
It's very common.
Do it yourself.

[7981GS]

And, the threads/bolts can be deeper in the blind holes in which they thread.

I had to do the same thing in my '82 GS1200G project with grade 10.9 Allen head bolts...




Eric

[TheCafeKid]

And use a torque wrench this time

Those have a specific torque, and while all the rest of the bolts onthe bike do too, THOSE are imparitive to have correct for this very reason among others..

Before I was taught in the ways of the GS, I used to tighten things like case cover bolts up until they were tight. Tight.
Once I was schooled, and started torquing things to correct values, I was amazed at how much I'd been over-torquing things, and amazed that I hadn't managed to strip the hell out of a crap load of holes.
Alu is soft...

[7981GS]

And use a torque wrench this time

Those have a specific torque, and while all the rest of the bolts onthe bike do too, THOSE are imparitive to have correct for this very reason among others..

Inch-pounds...



7 foot pounds=84 inch pounds (simple math)


Eric

[TheCafeKid]

Inch-pounds...



7 foot pounds=84 inch pounds (simple math)


Eric

6.0-8.5 ft lbs.

But Eric/Daniel is correct, if you've got an inch/Lb wrench, use it. Most torque wrenches are less accurate at the extreme ends of their adjustment range.

[musicman]

Torque wrenches are money savers

[Steel Toed Tank]

I have a Snap-On, might be a little while before it SAVES me any money, lol.
But yeah, torques aren't suggestions.


Tank

[JimmyR]

FWIW I DO have a torque wrench. I said I didn't have it anywhere near tight. Why do you all assume I wasn't using a torque wrench? And I'm reluctant to use any different kind of bolts because the manual - which I am repeatedly told to follow religiously here - says not to use any other bolts because they won't be strong enough.

I haven't installed a helicoil before and sure ain't going to use my cams to learn how to! So as long as a helicoil is ok here that's what I will use, and I'll get my machinist friend to do it for me!

Cheers!

[Nessism]

Did you clamp down the camshaft into the head the way the service manual instructs before you installed the bolts? If not, pulling the cams down into the head, against the force of the valve springs, places a lot of needless load on the cap threads.

Not saying you did this, just a caution in case you did, or if someone else is reading this thread - it's an ongoing learning experience for all of us.

Good luck

[chef1366]

FWIW I'm out.

[JimmyR]

Yeah I did everything according to the manual. Maybe it's just one of those things? Maybe it was like that before? Who knows. Thanks for the help anyway guys - I can get it fixed so onwards I go.