The SOHC/4 Owners Club relies on the support of our members. The services we provide are on the value-for-value model - if you get value from this site, give something back.

Click here to donate

Author Topic: Exhaust stud removal  (Read 1577 times)

0 Members and 1 Guest are viewing this topic.

Offline Sherlock

  • Full Member
  • *
  • Posts: 89
    • A Cafe Racer is Born
Exhaust stud removal
« on: September 23, 2012, 04:19:24 am »
Looking for help and advice.

CB550f2 ss

Managed to remove 3 studs but the others are stuck fast. 

I have snapped 2 :-( the remaining 3 have been heated, soaked (for a week) and I've used various thread removal tools.
One of the studs has been replaced with a slightly larger one.
Can the sheared off studs be drilled out and Heli coiled?
Any other advice before I take it to a machine shop?

Sent from my iPhone 4 using Tapatalk!

Online Terry in Australia

  • Really Old Timer ...
  • *******
  • Posts: 27,015
  • So, what do ya wanna talk about today?
Re: Exhaust stud removal
« Reply #1 on: September 23, 2012, 05:13:31 am »
It depends on what equipment and skills you've got mate. If you can drill the broken studs out at the exact correct angle, then it's easy enough to go small-bigger-biggest with the drill bits, then use a helicoil kit to replace the drilled out threads.

You might get lucky and get the broken ends out with "Easy Outs" (a contradiction of terms, if ever I've heard one) but don't count on it. It's super important that the studs are drilled at exactly the right angle though, and if you don't think you're capable, take it to the machine shop.

How have you been heating the studs? You need plenty of heat, either a propane torch (good) or an oxy-acetylene torch. (better) Get them hot, not hot enough to melt them, but a nice "dull cherry" color is good. You can "double nut" them if you're gonna try to save them, or grab them with vice grips and undo them while they're still nice and hot. I've found that a combination of heat and quenching with WD40 works well for me, but there might be a better way. Cheers, Terry. ;D 
I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

Offline mono

  • Definitely no
  • Expert
  • ****
  • Posts: 1,271
  • 1975 Honda CB550, 1978 CB750K (in progress)
Re: Exhaust stud removal
« Reply #2 on: September 23, 2012, 05:53:48 am »
Yikes I'd be ultra careful using oxy-ace around aluminum!   

Sent from my SPH-L710 using Tapatalk 2

Offline Retroben

  • Full Member
  • *
  • Posts: 48
  • '78 CB550K
Re: Exhaust stud removal
« Reply #3 on: September 23, 2012, 04:06:04 pm »
The broken ones you're going to have to drill, and if you don't have precision drilling capability, you will only make matters worse. Take it to a machine shop. If you do have a good precise drill press and the right bits, you might try drilling very small in the center of the broken stud, then gradually larger until you get large enough to insert the smallest size (professional quality!) screw extractor you can find - after soaking with penetrant and heating. But remember this steel-to-aluminum can stick incredibly tight, so you might then end up with more trouble in the form of a broken extractor ("easy out", right, like diarrhea).  Unless you're a machinist, don't be penny-wise on this one. Trust me.

If you're taking it to a machine shop anyway, let them do the whole job - including removing the remaining studs (if necessary). You might order the studs in advance and take them in with you, unless your local machine shop has the equivalents in stock (don't count on it).

My two pence/cents/pesos worth.

Offline SOHC4 Cafe Racer Fan

  • Speak up, Whipper-Snapper! I'm a
  • Really Old Timer ...
  • *******
  • Posts: 15,039
  • SOHC/4 Member #1235
Re: Exhaust stud removal
« Reply #4 on: September 23, 2012, 06:19:59 pm »
++++1. I would not attempt the extraction without the right equipment and expertise.
1975 CB550K1 "Blue" Stockish Restomod (
1975 CB550F1 frame/CB650 engine hybrid "The Hot Mess" (,150220.0.html)
2014 MV Agusta Brutale Dragster 800
2016+ Triumph Thruxton 1200 R (,170198.0.html)

"There are some things nobody needs in this world, and a bright-red, hunch-back, warp-speed 900cc cafe racer is one of them — but I want one anyway, and on some days I actually believe I need one.... Being shot out of a cannon will always be better than being squeezed out of a tube. That is why God made fast motorcycles, Bubba." Hunter S. Thompson, Song of the Sausage Creature, Cycle World, March 1995.  (

1973 CB750K2 "Bionic Mongrel" ( - Sold
1977 CB750K7 "Nine Lives" Restomod ( - Sold
2005 RVT1000RR RC51-SP2 "El Diablo" - Sold