Broken off bolt

[Okie]

After getting my '74 XS650A running, I let it sit for a while. Decided it's time to do some riding, so I'm going to change sprockets & fix some leaks. I took off the left cover & started cleaning. You couldn't see anything under a thick layer of dirt & oil.
I noticed a bolt missing in the lower part of the starter reduction gear cover. No problem, I have a spare parts engine. It wouldn't start! The PO had put the cover on with a THICK layer of sealer, not only on both sides of the gasket, but in the bolt holes as well! So after spending quite a bit of time getting that off, the missing bolt is a sheared off bolt. I drilled it and have been trying to use an easy out, but cannot get it to budge. I don't want to snap off the easy out in the bolt. Sprayed it with PB blaster.
Anybody have any ideas on how to get it out?

 

[Signal]

This is what I would do in order of preference.
1. Try heating the case with a heat gun (warm air).
2. Use the arc welder method. Look on you tube if you don't know how it is done.
3. Ignore it until you pull the motor out. Then try 1 and 2.
4. As a last resort drill it out.
In the end you will do what you feel comfortable doing.
I have done more damage trying to drill out broken bolts than I have done removing stuck bolts with an arc welder.

 

[jayel]

heat it, PB blaster, if it's centered good drill with left hand bit, drill with larger bits until you can peel out threads, drill and install heli-coil

 

[Okie]

It's in such an odd place that drilling is difficult, the drill is hitting the frame. I would have to get a much longer drill bit. Getting a good purchase on the easy out is also difficult. I haven't tried heat yet. I'm going to see if I can find a better extractor, the spiral kind. I really hate the thought of ignoring it OR pulling the engine.
Thanks for your thoughts guys.

 

[gggGary]

IMHO quit already with the easy outs. They are seldom the best method to remove a bolt. use a LH drill bit, put the cover on use a bushing, that will keep your drill bit centered. The bit will catch the remains of the bolt and it will thread out as you drill.

the drill size to tap 6mm is 5mm, 3/16" is just shy of that so is a good choice.
3/16" 0.1875" 4.7625mm

A set of LH drill bits is like $10 at your local auto parts store.........
EDIT:
weld an extension on the drill bit to extend the reach.
No bushing? grab a 6mm allen head and drill through it with the 3/16" drill there's your bushing. Spending $20-25 on tools will seam VERY cheap if you muck up a crankcase by improvising. you could get a 3/16 long shank bit for a couple of bux at the home center. start the hole with that then switch to the LH held with a needlenose vicegrips.

 

[fredintoon]

It's in such an odd place that drilling is difficult, the drill is hitting the frame. I would have to get a much longer drill bit. Getting a good purchase on the easy out is also difficult. I haven't tried heat yet. I'm going to see if I can find a better extractor, the spiral kind. I really hate the thought of ignoring it OR pulling the engine.
Thanks for your thoughts guys.

Hi Okie,
EasyOut is a black lie! When (not IF but WHEN) the EasyOut snaps off in the stud you will find that it's stub is far harder than any known drill bit and you are into the hassle and expense of pulling the motor, stripping the part down to a bare casting and paying the big bucks to get the stub removed with a Sparkatron.
(EDM, electric discharge machine).
I see the same access problem with installing a Helicoil in situ as you have found in drilling the stud out.
I'm sorry but I think that unless you are very lucky you are f**ked for an in-frame fix.

 

[CDNTX650]

I would honestly leave it, make a new gasket, use some a light coat of yama bond, see if you can get something to keep pressure close to that missing bolt on it till it sets up. If it never leaks good riddance till the motor comes out.

Posted via Mobile

 

[gggGary]

To expand on why easy outs are a bad idea. That's the reason. The tapered shape EXPANDS the bolt as you force it in making it an even tighter fit in the soft aluminum crankcase. It's easy to see why an easy-out is a fast trip to ruination. Easy-out's do have their uses but a LH drill bit is the much better choice in most bolt in aluminum cases.

 

[Okie]

To expand on why easy outs are a bad idea. That's the reason. The tapered shape EXPANDS the bolt as you force it in making it an even tighter fit in the soft aluminum crankcase. It's easy to see why an easy-out is a fast trip to ruination. Easy-out's do have their uses but a LH drill bit is the much better choice in most bolt in aluminum cases.

I've had experience (bad) with easy outs before, & yes they are extremely hard metal. That's why I was hesitant to apply too much force. Thought it might break loose easily (not). I'm might try a LH drill bit. I'm not going to ruin the cases.

Got a phone call out of the blue yesterday afternoon from someone I know selling his 750 kitted '75 XS650B, Mikuni's, Boyer ignition, 2-1 exhaust. He said he thought of me because he knows I have a collection of these, (mostly parts). He has maybe 9K on it since rebuild, about 25K total, and it seems to run well. Says he's getting too old. He bought it in the condition it's in.
If I can talk him down to a reasonable price, I may just buy it and just pull the motor on this one to do it right. I already have the parts for a new top end, plus rebuilt 35mm dual disc forks ready to install. Surely I can find a way to have fun and not spend too much more money than I already have. Thanks for sharing your knowledge, the main reason I love reading on this site every day.