Topic: Mix & Match Cylinder Studs?

[sammermpc]

Just got off the phone w/ a guy at the machine shop — he managed to pull the two studs I'd broken off in my 72 CB500 crankcase, but recommended that I leave the remaining 6 in (I got some of the others off myself). He said that it'd taken him two-hours alone just to remove the two.

So question — I have a set of APE studs. Can I just replace the ones that I've got out and use the stock ones for the others?

I hate doing things things like this, but I don't think I can pull the studs myself, and I can't afford to have him pull the rest. At that rate, I should just find a new motor.

[Trad]

The only thing that's off is that the stock studs and the ape studs take different torque values. This would put uneven tension on the head. If you want to put it together mixed and matched it's not like anything is going to explode, it's just not totally ideal.

[tlbranth]

Why not spring for 2 matching studs?

[sammermpc]

If you want to put it together mixed and matched it's not like anything is going to explode, it's just not totally ideal.

Well, as long as it doesn't explode. Ha. That's a vote of confidence if I've ever heard one. For what it's worth, I think I've got off two on one side, three on the other, so it'd be "mostly" even...

Why not spring for 2 matching studs?

Well, it's five, I think — but that's definitely a good thought. I could see about returning or selling the APE studs. Honestly, after the misery I've had with these guys, I'd love to stick w/ the beefier ones, but that isn't looking like an option.

Some masochistic part of me wants to split the cases and replace it w/ APE studs, or put it in an oven to see if I can get the old ones out. Based on my track record w/ this baby, I'm guessing that'd mean I wouldn't be riding at all this summer.

[Retro Rocket]

Just got off the phone w/ a guy at the machine shop — he managed to pull the two studs I'd broken off in my 72 CB500 crankcase, but recommended that I leave the remaining 6 in (I got some of the others off myself). He said that it'd taken him two-hours alone just to remove the two.

So question — I have a set of APE studs. Can I just replace the ones that I've got out and use the stock ones for the others?

I hate doing things things like this, but I don't think I can pull the studs myself, and I can't afford to have him pull the rest. At that rate, I should just find a new motor.

And thats why he works in a machine shop and not a mechanics workshop....   Take the old studs out and replace the lot, studs stretch and fatigue over time, a new set will torque differently to an old set and its not uncommon to break old studs whilst trying to reuse them. The other problem could be oil leaks due to differing torque settings or even a stud letting go later on. I had an old hipo engine do just that after reusing the 35 year old APE studs torqued back to their original specs.

[Phinn]

Bend them over and twist them all out!

[SOHC4 Cafe Racer Fan]

Those mixed unmatched torque values could land you with a leak.  Just bite the bullet and replace them all.  You've already purchased the HD stud set, after all.

[calj737]

Heat the dog piss out of them, then whack the top of the them with a mallet. Then, use a stud puller and turn them out. You can add a little PB Blaster during heating, but the whack and turn works wonders. (And I do mean dog piss hot! Point the propane at the threads to focus the heat.

[tlbranth]

Heat the dog piss out of them, then whack the top of the them with a mallet. Then, use a stud puller and turn them out. You can add a little PB Blaster during heating, but the whack and turn works wonders. (And I do mean dog piss hot! Point the propane at the threads to focus the heat.

I'm wondering if heating the aluminum that much and then strong-arming the assembly isn't asking for stripped threads.

[sammermpc]

Hahah, well guys — I don't know. I've racked enough in machinists bills as is — the going rate there is $95 an hour. He said it took him two hours to pull out the two sheared studs. A bit steep, yeah? Ouch. At that rate, I should've just bought a welder. I'm moving in the next couple months, though, so didn't want the extra baggage. I spoke with another shop that's $60/hour, so I might try them next time around.

Anyhow though — thanks for the encouragement. I do feel like pulling the studs will make me happier, even though it might get me in hot water. I'll slam, blast, etc., them (carefully!) and hold ya'll responsible if I snap any more. 

I did find a nice set of stud pullers, so that may help, but we'll see. I'll let you know how it goes. The one common thread in all these removals is banging the hell out of the stud, so I'll start with that.

[sammermpc]

Just wanted to update — all the studs out! Last one needed to be drilled and helicoiled (which I'm a bit unsure about) — but I did get them out, so I'm pretty happy. Thanks for all of the help!

Basically, it was really just patience. I'd go out once in the morning (usually), and in the evening—heat up the studs, hit them with a hammer, and douse them in kroil. Eventually, one by one, they gave. In some cases, you could see it happen—the kroil would suddenly penetrate and start bubbling. I tried beeswax, FreezeOff, and other stuff as well, but I really think it was just the patience and the steady alternation of heat, cool, + tapping with the hammer. All told, it took more than two weeks.

[SOHC4 Cafe Racer Fan]

Just wanted to update — all the studs out! Last one needed to be drilled and helicoiled (which I'm a bit unsure about) — but I did get them out, so I'm pretty happy. Thanks for all of the help!

Basically, it was really just patience. I'd go out once in the morning (usually), and in the evening—heat up the studs, hit them with a hammer, and douse them in kroil. Eventually, one by one, they gave. In some cases, you could see it happen—the kroil would suddenly penetrate and start bubbling. I tried beeswax, FreezeOff, and other stuff as well, but I really think it was just the patience and the steady alternation of heat, cool, + tapping with the hammer. All told, it took more than two weeks.

What do you mean by "kroil"?

[sammermpc]

Kroil Penetrating Oil — I saw it recommended on some forum somewhere and bought it. It's just a light, penetrating oil, I think, probably not so different from PB Blaster, but it worked really well and didn't get everywhere like the spray oils. Kind've pricey, but a little goes a long way, at least in my experience.

[SOHC4 Cafe Racer Fan]

Thanks.  I wasn't sure if it was a brand name or acronym/nickname.

[calj737]

Kroil is quite popular in the shooting world. It's excellent at protecting barrel rifling, actions, etc. Penetrates quickly and leaves a very light film behind (desirable for accuracy).