Not trying to step on
jamiesix's toes here but I am going to chime in before you make a common mistake and heart-ache...
Note: The only way I got good at broken bolt removal is by breaking WAY too many bolts in my days.
I would not jump right to an "easy-out" they are extremley hard and threrefore brittle... very easy to snap off. Then a broken easy-out is next to impossible to remove without help from a machine shop. Also an easy-out's tapered shape expands the bolt and can wedge it even tighter.
Do not use WD-40, it is not a pentrant, it's silicone preservative / water dispersant (WD).
Get a good penetrating oil. PB Blaster, Kroil, or believe it or not, a homebrew 50/50 mix of acetone and Transmission fluid (ATF) is best. Spray it down repeatedly.
Then a center punch right smack dead center on the broken bolt. you can start light taps to verify your in the center but you want to finally give it a good stout "whack". This does two things...
1. It gives you a center point to keep the drill bit from walking
2. Shocks the threads and breaks the corrosion hold for the penetrant to soak into.
If there is a peak in the break at the center, your drill will walk to the edge and you'll damage the threads.
If you have a Dremel you can use the smallest round headed burr to grind a starting point in the center. But you still want to center punch it to help break loose the corrosion on the threads
Spray it down again and let it soak it a MINIMUM of over night.
Pick up a set of "Left hand" drill bits. To use these you need a reversable drill.
Start with the smallest bit and with your drill in reverse carefully drill a pilot hole exactly centered and straight into the bolt. With any luck it will back out with this first drilling. If not, jump up a couple sizes and this time go slowley. The larger bit will want to follow your first pilot hole but you still need to stay centered and straight.
The sharp edge of the bit will bite into the bolt and usually back it right out.
You can use a propane torch and gently heat the surrounding aluminum but be careful and quick. The aluminum will expand faster than the steel bolt at first and thats you window to work in... but once the heat transfers to the steel it expands as well. On this particular cam tensioner bolt there is a rubber plug really close so don't over do it.
Several small heat and cool cycles will also let more penetrating oil soak in so spray it after each heating. Then try drilling again.
IF this all does not work, then you can try an easy-out. BUT they are not all alike.
Ridgid makes a good set and Snap-on / Mac tools has a similar version (read expensive) but the original from Ridgid are THE BEST!
Notice a couple things in this set? The extractors are straight, not tapered. They are actually a star shaped rod with sharp points to grab and you tap them into the hole with a hammer. Each extractor has the properly sized drill bit. Each size also has a centering guide (along the bottom) to help you drill the hole straight. Finally, along the right side is the adapters that fit the star shaped extractor and you can use a 6 or 12 point wrench or socket on intsread of the four flats on a regular "easy-out".
If you choose to use a regular old fashioned "easy-out", use a Tap handle on it. That will fit the four sided end much better than a open end wrench and make it much easier to control.
Do NOT heat it. That seems to make them even more brittle and easier to break. Carefully and slowly try but go straight into the hole and feel if it is working. Remeber the taper? Watch for expansion of your broken bolt and if the easy-out starts to twist at the top but not at the bottom STOP.
Soak it with more pentrant and leave it over night then try again the next day.
That's as much of my experiance I can think to pass on. Good luck to you!
81 Honda CB750C - Current Project
67 BSA Spitfire MkIII - Next Up (Full Resto)
81 Honda GL1100 - Bob / Cafe´
80 Suzuki GS750L - Bratstyle
72 Honda CB450K5 - Basket Case
73 Honda CB350F Cafe' (Gone but not forgotten)
Don't wait for opportunity to knock... kick the door down and drag the old harlot in!
Locked
Are the pistons that rough of a texture from some sort of corrosion,or is that just how the casting looks?
