I would do this AFTER the side cover is off...... you said 1/4 of the head is still there; this would not be easy to get a good center spot

just leave it until you actually need to take the side cover off if its not leaking you should be OK.

you should be able to pull the cover over that damaged head (if it is leaking) and the cut it flat and center punch it; revers drill bit.......or if there is lots of stump left vice grips are quick and easy.

 

Funny thing about that exact bolt, I have taken it off a couple of times by mistake. It looks like the one that should be on the sprocket cover and then I realize that I did the wrong one. I need to pay more attention, I don't want to end up doing the same thing. Let us know what happens, oh and be sure to take pictures if you can so that we can see how it goes.

 

That is EXACTLY what I did. I remember thinking "funny, I don't remember 3 bits holding this on...oh well I'm late lets do this..." I just bought a brand new craftsman socket set...turn, click, turn, click, turn, click....turn...turrn!! turn!? NOO!!!

I'm pretty sure there is no specific torque rating for this piece, so be careful guys! Just get it hand tight plus a small turn of the wrench! That is what "secure" means...not turn it and turn it waiting for it to get really hard to turn...because it'll just twist right off!

By the way, I believe that is the cover for the flywheel/starter clutch. There is a magneto in there. I think I should be pretty secure, as the magneto holds the cover in place, and it's recommended I use a rubber mallet to break the cover free once all 8mm bolts are removed.

 

Definitely use the easy out. you can goto your local sears and buy a set for about 30-50.00.

You other option is goto your dealer and buy the bolt. Find the thread size and pitch. Then goto your local autoparts store, something major like a napa or one with a tool selection and buy a helicoil set for your particular size and thread pitch of bolt.

I would go the easy out route first.

 

I agree with "easy-outs". But before you actually drill it, make sure you use a small small small punch to make a dimple in the center of the remainder of the bolt, so that your drill bit doesn't slide all over the place when you are attempting to use that small drill bit before you use your "easy-out". Take it slow man.

 

definitely take it slow, if you break an easy out in their your up the creek! No drilling out something thats hardened.

 

I would be taking the cover off first and then seeing how to do it from there.
If there is enough sticking out to grip it with vice grips, there is less chance if it endind in tears. IMHO
These things can easily end in a stripped or damaged thread.
Then it's time for one of these bad boys.


To be avoided.

 

Once the head of the bolt is broken off what is left is not as tight (or torqued) as much as you think. You can buy an individual easy out at ace hardware for less than ten bucks. Make sure you have the right size easy out and the appropriate (quality) drill bit. Carefully drill the hole. It will come right out. The easy out is ten times stronger than it needs to be in this situation.

 

personally something like that i would take to someone that is experienced in dealing with and eat the cost... might end up saving you alot of money in the long run.

 

Done this so many times with old Jap' bikes. The UK climate is a disaster for old metal.
Drain the oil. Take the cover for the magneto off. Try some vice grips first. If you have no success and there is some of the bolt shaft showing. Take a suitable nut, place it over the broken shaft and tack weld it on. Presto, new hex head to put a spanner on. Hasn't failed me yet and I've never had to resort to a Helicoil. All you need is someone with a welder, but try the vice grips first.