Dang It! I pulled out a head stud - suggestions please!

Mark · Mar 26, 2012

If it ain't one thing, it's another.

This morning getting ready for work, I roll the bike out and see a little oil on one of the side covers.
Upon further investigation I see the head gasket is leaking under the carb.

I grab a 13mm. wrench and as soon as I put a little pressure on the nut, it got real easy to turn.

I knew exactly what happened so I pushed the norton back inside and took my other bike to work.

When I got home I took the head off and sure enough, the threads are stripped out of the head.

What is the best way to repair this? Helicoil? what size? Oversized stud?
How would you fix this ?????????

Dang It! I pulled out a head stud - suggestions please!

comnoz · Mar 26, 2012

Copied from an earlier post

About the only time Commandos blow head gaskets is if the bolts come loose or a stud pulls. I normally re-tap the three stud holes for a 3/8 inch coarse threat helicoil insert. Then I install studs from ARP which are coarse on one end and fine on the other. Then I can use an ARP 12 point nut which only uses a 7/16 wrench on the rear stud. No more clearance issues. I install 3/8 inch fine thread helicoil inserts in the long nuts for the two front studs.

I do this before I use any head- even a brand new Fullauto.

The coarse thread helicoils hold much better in the aluminum head than fine thread. If British helicoils are used to repair the stud holes they will eventually fail again. The 3/8 coarse helicoils will hold very well as long as the head has not been overheated by welding. Jim

If you don't want to go for ARP studs you can take an old head bolt and cut the head off. Then thread that end with 3/8 coarse thread and you will have a stud that will fit the original nuts. Jim

Mark · Mar 26, 2012

comnoz said:
If you don't want to go for ARP studs you can take an old head bolt and cut the head off. Then thread that end with 3/8 coarse thread and you will have a stud that will fit the original nuts. Jim

Great Idea Jim!
I'm gonna go back out and make me a stud right now.
I'll pick up a helicoil tomorrow.
The old girl shouldn't be down for too long.

comnoz · Mar 26, 2012

Mark said:
comnoz said:

If you don't want to go for ARP studs you can take an old head bolt and cut the head off. Then thread that end with 3/8 coarse thread and you will have a stud that will fit the original nuts. Jim

Click to expand...

Great Idea Jim!
I'm gonna go back out and make me a stud right now.
I'll pick up a helicoil tomorrow.
The old girl shouldn't be down for too long.

Make three while your at it. Now or later.

Jim

mikegray660 · Mar 26, 2012

Jim, i'm surprised you'd use a helicoil as opposed to a time-sert

I've found time-serts are way more permanent (aka less prone for winding out again etc) than a helicoil - thoughts?

(oh and that a pretty clean looking head?!)

m

Mark · Mar 26, 2012

comnoz said:
Make three while your at it. Now or later. Jim

It's going to have to be later. I dug into my stash an only found 2 head bolts.

I cut one to size and threaded it no problem. ready to go.
If this fix works (and I have no doubt it will), I'll have no issue repairing the other studs
should this happen again.

I have never had it (pulled stud) happen on a motorsickle before but it must be a common enough
occurrence with norton heads that you have developed a preemptive fix.

Mark · Mar 26, 2012

mikegray660 said:
(oh and that a pretty clean looking head?!)

m

Carb Cleaner and a scotch brite pad.
(I don't care for working on dirty parts.)

comnoz · Mar 26, 2012

mikegray660 said:
Jim, i'm surprised you'd use a helicoil as opposed to a time-sert

I've found time-serts are way more permanent (aka less prone for winding out again etc) than a helicoil - thoughts?

(oh and that a pretty clean looking head?!)

m

I use time-serts when the british helicoils pull out.
I guess I have stuck with coarse helicoils because I have been doing them that way for 30 years and have not had one fail or un-screw with the stud yet. Jim

SteveA · Mar 27, 2012

Jim,

ARP products, do you have part numbers? or do they do specific Norton parts? big catalog for the unititiated!

Steve

stockie2 · Mar 27, 2012

Great post guys, I have a front stud pulling. I can feel it is not taking up, but I have not pulled it yet. Bugger it. I had a engineer repair the studs and I can only guess he used the fine british threads with a heli-coil. And it failed just like Jim said it would. So from what I read, I am going to have to use one of the time zert thingo's?
I would be interested to know what the ARP fasteners are and where you can order them from in Australia?

Cheers Richard

comnoz · Mar 27, 2012

SteveA said:
Jim,

ARP products, do you have part numbers? or do they do specific Norton parts? big catalog for the unititiated!

Steve

Here is my last invoice. The head studs and a 10 pack of nuts are underlined. The nuts are available separately. http://arp-bolts.com/

While your at it. Three studs with hardened washers and good nuts will cure the problems with keeping the engine and cradle bolted together. They are on the invoice also. Note- pre MK3 engines use a 5/15 stud in the lower hole. You can either drill the hole out to 3/8ths or get a 5/16 stud which I don't have the part number for. You need to ask as by dimensions as they are not in the catalog.

Mark · Mar 27, 2012

Jim - you are The Man!

splatt · Mar 27, 2012

Once helicoiled the studs are a bit short, more so on the front two, Ludwig posted a good thread on making new longer head studs

marinatlas · Mar 27, 2012

Hi Jim, thank you for the specs of the studs...!

Mark · Mar 27, 2012

Got it done!
but not without a little hassle. The stud that I made last night....... I cut the wrong threads on it. :roll:
A coarse thread Helicoil is 3/8 - 16. I put 3/8 - 20 threads on the stud.

I caught the error when I was at the store so I just ended up buying 3 3/8-16 X 3/8-24 studs ( they didn't have ARP)
and planned on replacing all three on the head.
While repairing the first, I realized that if I replaced the 2 in the front which are still OK, then I wouldn't be able to use
the stock long nuts.
So I just decided to leave those two alone until they finally give me trouble.

The repair was pretty easy, the head is back on the bike, torqued and adjusted, I just got to put the exhaust and carb back on and
then I can fire it up. I got tired of messing with it for today, I'll finish it up tomorrow.

splatt · Mar 28, 2012

That helicoil is no good, they should be wound in another turn, that one will cause you problems and probably pull out

mikegray660 · Mar 28, 2012

splatt said:
That helicoil is no good, they should be wound in another turn, that one will cause you problems and probably pull out

+1 on that :shock:

comnoz · Mar 28, 2012

Glad you got it back together. As pointed out the helicoil should be in deeper although I doubt that it will give you any trouble as is. Next time you have it apart I would be tempted to pull it out and tap it a couple turns more. If the end of the helicoil is a couple threads below the surface there is no chance of it coming out. Jim

Mark · Mar 29, 2012

Thanks Jim!

Yesterday I finished putting it together and rode 22 miles, just to warm it up.
Today I re-torqued the head and did 85 more miles.
The stud is still holding up. So far - So Good.

Honestly, I'm getting kind of tired of working on it, I just want to ride it!
So far this year I have put a total of 616 miles on it.
Not too bad considering spring has just sprung and I live at 6,000 feet elevation.

The Norton is parked for the weekend because we are leaving in the morning to
ride 1300 miles across Northern Arizona (Monument Valley, Grand Canyon, ETC).
on my Valkyrie.

Nice weather - Gotta Ride!

Hobot · Mar 29, 2012

Honestly, I'm getting kind of tired of working on it, I just want to ride it!

Ugh, don't we all, so get back in the line please. Must fix em to ride em then riding them means we must fix em. Its a tester of your manhood to steal from rest of life to give to you Commando and risk of pure fate on what may be next show stopper. I got ~7000 miles out of my last Combat rod bolt up re-build, and still running good but smokes so much from copper head gasket I assume I skipped on re-torque too much on, will be torn down to piston rings this after noon so maybe I can enjoy the week end and beyond on it w/o fogging the road like wounded airplane. Reading this forum helps me get on with it instead of just taking it easy working on practical stuff like mower or car/truck/house/shed and what not. Already procrastinated almost a week now.

Dang It! I pulled out a head stud - suggestions please!

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