Broken Bolts
- nickleo373
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Broken Bolts
23 Feb 2015 16:39
Hey everyone
I was in the process of replacing the valve cover gasket on my 81 Kz550. While I was torqueing down the valve cover bolts I had two of them snap leaving pieces in the valve cover and head. I believe I can probably remove the smaller bolt with an easy out or something but does anyone have any suggestions about how to remove the long cam end screw that broke off?
I was in the process of replacing the valve cover gasket on my 81 Kz550. While I was torqueing down the valve cover bolts I had two of them snap leaving pieces in the valve cover and head. I believe I can probably remove the smaller bolt with an easy out or something but does anyone have any suggestions about how to remove the long cam end screw that broke off?
1981 KZ550C LTD
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Re: Broken Bolts
23 Feb 2015 18:11
No, but you may want to invest in a torque wrench calibrated in inch pounds so you can properly torque the bolts without breaking them. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- nickleo373
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Re: Broken Bolts
23 Feb 2015 18:34
I just bought one specifically for putting the valve cover back on. I think the old bolts were just weakened. I probably should have thought ahead and bought new ones

1981 KZ550C LTD
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Re: Broken Bolts
23 Feb 2015 18:35
I wonder if the specs were correct? Do you recall how many inch pounds they called for? Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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- nickleo373
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Re: Broken Bolts
23 Feb 2015 18:38
According to the Clymer manual the valve cover bolts are all 90 in pounds
1981 KZ550C LTD
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- ricko1966
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Re: Broken Bolts
23 Feb 2015 18:59 - 24 Feb 2015 20:41
If they broke from over tightening they should come out real easy.if you can cut a slot with a dremel they should come out relal easy with a screw driver. I worked in an automotive parts,repair and machine shop from 1985=2001 I cannot recall us ever using an easy out and we always warned people not to use them.An easy out is harder than a drill bit and if it breaks you cannot drill it out.By nature the eazyout is tapered causing the bolt to expand more the more pressure you put on it.My favorite method of taking out broken bolts that are frozen in place is put a nut over the bolt if it is flush or sticking up a little weld through the center of the nut to the bolt touch a crayon to the bas
e of the nut and wax will wick into the threads just like soldering pipe
while everything is still hot,expanded and lubricated put a wrench on the but and back out your bolt like magic.Your bolts shouldn't be seized if you can even nick the end with acchisel you should be able to walk them out or get a left hand drill bit they should walk out while you run your drill counterclockwise
e of the nut and wax will wick into the threads just like soldering pipe
while everything is still hot,expanded and lubricated put a wrench on the but and back out your bolt like magic.Your bolts shouldn't be seized if you can even nick the end with acchisel you should be able to walk them out or get a left hand drill bit they should walk out while you run your drill counterclockwise
Last edit: 24 Feb 2015 20:41 by ricko1966. Reason: spelling
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Re: Broken Bolts
23 Feb 2015 19:11 - 23 Feb 2015 19:12
"According to the Clymer manual the valve cover bolts are all 90 in pounds."
That seems very high for 6mm bolts. The KZ550 Kawasaki Service Manual calls for 87 inch pounds, but frankly I believe that is also a bit high. My KZ650-C1 also uses 6mm cylinder head cover bolts. In fact, they are the exact same part number as the 4 long bolts on the ends of the KZ550 cover. The torque spec given for them in the KZ650 Kawasaki Service Manuals is 61-78 inch pounds. I have always tightened mine to 65 inch pounds and have never had a leak. I suggest you try using 65 inch pounds and see if you also have no leaks. Ed
That seems very high for 6mm bolts. The KZ550 Kawasaki Service Manual calls for 87 inch pounds, but frankly I believe that is also a bit high. My KZ650-C1 also uses 6mm cylinder head cover bolts. In fact, they are the exact same part number as the 4 long bolts on the ends of the KZ550 cover. The torque spec given for them in the KZ650 Kawasaki Service Manuals is 61-78 inch pounds. I have always tightened mine to 65 inch pounds and have never had a leak. I suggest you try using 65 inch pounds and see if you also have no leaks. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Last edit: 23 Feb 2015 19:12 by 650ed.
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Re: Broken Bolts
23 Feb 2015 19:18
No need to torque valve cover bolts,start in the center and snug them up with a 1/4" drive or a stubby 3/8 drive ratchet working your way out to each end.
Do you have a picture of the head where bolts are broke?
Do you have a picture of the head where bolts are broke?

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- nickleo373
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Re: Broken Bolts
23 Feb 2015 19:59
Thanks Ed. If I am able to get these two out of the engine I'll be taking the rest out and replacing them with new bolts and torqueing them down to 65 in pounds instead. Here are pics of where they broke. The broken one on the air cleaning thing shouldn't be too hard to remove because it is only in the valve cover. The second one that is broken is broken into the head.
1981 KZ550C LTD
"If you ain't first, you're last"
"If you ain't first, you're last"
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- 650ed
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Re: Broken Bolts
23 Feb 2015 20:22 - 23 Feb 2015 20:24
If you have a bolt broken off below the surface or so short that you cannot grab it with vise grips I do NOT recommend trying to drill it and using an easy-out. It it far too easy for the drill bit to drift and hit the relatively soft aluminum head which will create an even bigger problem. Take a look at the links below that discuss EDM. It's a relatively new way of removing broken bolts, studs, etc. If you check machinists in your area you may find one that can remove the broken bolt without causing further damage by using EDM. If not, the machinist should be able to remove the broken bolt by more conventional methods. Ed
www.portableedm.com/
www.barretteng.com/products/electrical-discharge-machine/
www.portableedm.com/
www.barretteng.com/products/electrical-discharge-machine/
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
Last edit: 23 Feb 2015 20:24 by 650ed.
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Re: Broken Bolts
24 Feb 2015 04:48
Pull the valve cover off and see if the bolt is broke off flush ,or if theres something to grab on to.
If the bolts are broke off flush use a good center punch to mark the center,then find some place that sells machinist tools and buy a good left hand drill bit.As it drills into the bolt it will turn it out at the same time.
If the bolts are broke off flush use a good center punch to mark the center,then find some place that sells machinist tools and buy a good left hand drill bit.As it drills into the bolt it will turn it out at the same time.

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Re: Broken Bolts
24 Feb 2015 21:37
Thanks for the replies. I pulled the valve cover off again today and luckily there is about 3/4 inch of the cam end screw sticking out of the head. I'd rather not take a drill to it right away and risk slipping and damaging it more. I don't own a welder to reattach the head of the screw but does anybody know if using pipe solder to reattach the two pieces would work? I'm hoping I'll be able to just twist it off with a rachet
1981 KZ550C LTD
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"If you ain't first, you're last"
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