cylinder head bolts (not nuts)

guys im freaking pulling my hair out over here in iowa trying to reassemble my engine on my 750 kz four. we put the head on and torqued down the cylinder stud nuts to the correct torque (29 ft lbs). then we put in the bolts where the cam chain guides are (are you following me?). these cylinder head bolts are supposed to be torqued to 22 ft lbs. we torqued the front to 18 and then started to torque the one on the rear and it started to stretch. what i didnt tell you is that ive been through this before and actually stretched a previous bolt beyond usability. i dont understand. should i try getting harder bolts? could this potentially screw up the threads? i dont understand why this is happening, i bought a brand new bolt and stretched it in five minutes and made it useless. so right now i have both bolts installed and both around 18 ft lbs with the rear possibly stretched a little. does anyone think i should just leave this. what could happen if i did just leave it, leak oil. ill have to re torque the nuts after i run it, right? so will i have to re torque the bolts and this could possibly lead to them stretching even more. what makes things even more tricky is the fact that when i said ive had this happen to me previously, it happened on the front cylinder head bolt hole, and then it happened on the rear cylinder head bolt, which leads me to think that the bolts are soft and are just giving way... what the hell is going on? why is this happening? what do i do and what can be done or should not be done. im hoping that APE or Jay could possibly have something for me to implement but i shouldnt hold my breath. Jeff if you have any ideas either id be so very gracious. help me, someone, anyone!

my first thought is your torque wrench is messed up

two completely different torque wrenches were used. this cannot be.

so you think i should go get a third torque wrench?

Are you sure the bolts are stretching? That would be strange. The threads will strip real easy just like a camcap bolt. I'd recommend less than 18ft/lbs but who am I to say I guess. I just know I've stripped a lot of bolts in KZ heads soft aluminum, and I don't care if the manual says 50 ft/lbs. If it feels like it's too tight for the bolt to safely be tightened, use your own judgement. Less torque on these is not going to cause leaks of any kind.

yes the bolts are stretching, its discoloring in the middle and shaped like a coke bottle.

you think if i put titanium bolts in itll strip the threads out??


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the bolt holes are designed to take 22ft lbs so they should be ok ,BUT, dont get discouraged if they do strip ,it happens a lot with these old bikes.i think u realy have to suspect your torque renches if the bolts are stretching.you should prove to yourself that they work or not first.if u use 1 that is for foot lbs and u are on the low end of its range i would not trust it.i use 1 for inch pounds on those small bolts.just multiply by 12.

mark, i agree, my dad taught me this too. i used a wrench that has a max of 20 ft lbs so i wouldnt go over and had it set to 18 ft lbs. any ideas?


should i just buy another bolt and then get another torque wrench and try this again?

Just for info the factory KZ650 manual calls for 13-16 ft/lbs on these so maybe that is a better value to work with to avoid this.

that does help a little, it comforts me in the fact that it doesnt have to be cranked down like you said earlier.

though it still doesnt make sense. why would they put that in both the factory manual and the clymer. i just want some closure. or buy some hard bolts to get this whole stretching business taken care of. or something.