1982 kz1000 ltd J series cylinder head

So i was doing akme maintenance on my 1982 kz1000 LTD. Long story short. As i torque down the camshaft cap bolts, i initially stripped two bolt threads. Then repair those, re torque the camshaft cap bolts.

Now i have six more camshaft cap bolts have pulled threads.

Out of the 16 total camshaft cap bolts on my kz1000, 9 bolt holes have pulled the threads.

Cylinder head is still on the engine and frame, i will be prepping it for helicoil thread repairs on the six remaining holes i have to repair.

Anyone else encounter this or other problems with the aluminum material on kz1000 cylinder heads?

My exhaust stud on number 3 cylinder cracked last year. It was repaired, initially the screw sheared off, got it repaired, next day on the road the cylinder head casing around exhaust stud cracked.

Is my cylinder head cursed?

Very common situation when the exposed tips of the thread goes brittle..
Once one thread strips at the correct torque you can bet the rest will soon follow at subsequent intervals so it's usually best to do them all at the same time.

Been there, done that! One problem lies in the FSM showing 12 FOOT POUNDS on a M6 camshaft bearing cap bolt (page 1-9) . Yet in the back of the torque and locking agent section, it lists M6 course thread bolt torque specs at 52-78 inch pounds. Perhaps 12 foot pounds is a tad bit too much? The inaccuracies of the FSM were brought up a few weeks ago when comparing the Clymers manual the the Kaw manual. Reference page 1-12 in the 81-83 Kz1000 manual.

www.kzrider.com/modules/ServiceManuals/K...Service%20Manual.pdf

Too many G's! Let off! lol

STOP using a torque wrench on 6 x 1.00 mm bolts. Use a small 1/4" ratchet, you'll feel it when it's tight. A quality torque wrench for small fastners is very expensive so most people buy the cheap one's which are useless and leads to stripped threads.

Not sure if this applies but if you use the screws to compress the cams down into the journal saddles that puts a lot of stress on the threads. I like to use a pair of vice grips to clamp the cams down into the saddles before installing the caps. And if you use a torque wrench be sure to target the bottom of the torque range and only use a small in-lb torque wrench.

Also keep in mind that even the best torque wrenches lose accuracy the closer you get to the extremes of their range.

TexasKZ wrote: Also keep in mind that even the best torque wrenches lose accuracy the closer you get to the extremes of their range.

I tend to agree. They also lose accuracy when stored at the "cranked" setting last used. It is important to "unwind" a torque wrench to it's lowest setting (mine is marked at zero) , or eventually the calibration is lost from the internal spring being loaded when stored.

I feel that the actual torque setting is not as important as it is to having the fasteners all tightened evenly. The cam cap torque values in the service manual are obviously a typo, yet some folks may not realize this during engine assembly. Following the book values exactly while trying to do a good job the first time can sometimes cause you problems. Some days ya just can't win. :S

Nessism makes a good point to unload the fasteners with some sort of tool so that the threads are not having to overcome the valve springs to pull the cams / caps into place.

FWIW, 12 foot pounds is 144 inch pounds. (12 inch pounds = 1 foot pound) This is almost twice the recommended max torque value of 78 in-lb for the M6 bolt listed on page 1-12.