Cracked Rocker Base

[cheezer60]

Another dispatch in the heads from hell series:

I went through all of my rocker assemblies this weekend; cleaned and lubed all surfaces, measured end play, etc. I installed them back on the heads using new flexlock nuts, torque wrench, and proper torque sequence and specs.

Then...snap...I cracked the base on the pushrod/intake side of the rear head. It seems that the new flexlock nut was too tight on the stud, and forced the stud too far into the helicoil. The nut was threaded about halfway above the block...it wasn't that I was too heavy-handed.

I got the nut off of the stud, and re-installed the original flexlock nut, knowing it wouldn't bind as much as the new nut. The entire assembly is now torqued down to spec...but I wonder, will this be a future headache? The rocker assembly takes a beating from both sides, but with everything torqued down proper, it seems to leave very little room for the crack to expand. Thoughts?

[old.wrench]

Cheezer,
That crack doesn't look good. You can see how it's headed towards the front of the boss near the bottom. Heating, cooling, and vibration will probably push the crack further. I hate to say it, but it looks like a TIG job is in your future .

Those rocker block studs are usually threaded for an interference fit into the heads, sometimes you have to go easy on those buggers.

Geo.

[PanPal]

I just went through the same issue. I decided to not helicoil this because it gets thinner between the stud and side of the boss. I had it tig welded. Then any studs that turned easily were locktited. I set all studs heights at 1.450"

[Larry]

Studs and helicoils don't belong together.

[Bigincher]

Take a step back and take a deep breath.
You're going to want to fix that right with a weld job.
And probably machine the deck flat again.

[Huck]

Geeze that is some tuff luck. Being me the bike would never be fun, I’d be stewing on that. Some seriously heavy handed witness marks, yes?

[58flh]

Looking at the crack---As said it needs fixing,when I first read it I thought the end just cracked-off--But its not a bad setback!--A good welder & some homebrew crafting & you will be back on that build fast!.---Respectfully---Richie

[Tattoo]

Man what a shame..... I see no one has asked so I'll bite..... What are the 4 holes for?

[RUBONE]

I see no one has asked so I'll bite..... What are the 4 holes for?

Some seriously heavy handed witness marks, yes?

As noted in a previous post, they are punch marks (not holes). It is interesting how the crack ran right to them, a bit of a stress concentrator? And my vote is for welding and correcting the issue. The crack will continue if ignored.

[Tattoo]

As noted in a previous post, they are punch marks (not holes). It is interesting how the crack ran right to them, a bit of a stress concentrator? And my vote is for welding and correcting the issue. The crack will continue if ignored.

LOL Never would have thought to call them witness marks..... LOL Damn they knocked the hell out of it to make a dent that deep?? Why?? I don't know.....

Yep the crack went right through one of them that's why the question...

Most old metal won't take what the torque specs says... I just go by feel......

[cheezer60]

Thanks for the replies...to the machine shop they'll go.

I will force myself to think about this positively. While there, I'll have all of the 1/4"-20 rocker cover holes filled and tapped for stock hardware too, as I just got a set of oem aluminum covers and d-rings. Who loves guys who ride old iron more than the ladies? Machinists! $$$

Some seriously heavy handed witness marks, yes?

Right!?

Most old metal won't take what the torque specs says... I just go by feel......

Agreed- and I hadn't even come close to the torque specs on this particular nut. It wasn't even down to the rocker assembly before the stud cracked through. I'm going to look into some different hardware when they come back, because those flexlock nuts were binding way too much for my taste.

[Huck]

It’s not all bad, it might have gone together, and then let go 100 miles from home causing more damage. You’re right, it shouldn’t take any real torque to bring those nuts down, something is wrong there. I’ve seen all sorts of hillbilly stuff in parking lots & the side of the road, that’s what it takes sometimes. Make it as right as you can now, it’ll pay off down the road.

[Tattoo]

Ok... Someone explain what the witness marks are for other than making a weak spot? Is it for if it gets stolen?

[Larry]

The damage is close to the locating dowel; an issue when welding.

[cheezer60]

The damage is close to the locating dowel; an issue when welding.

Can you explain further?