Painful Lessons of Camshaft Work

Steel bolts in aluminum heads lead to a very tenuos situation. Aluminum used on KZ engines is surprisingly fragile - I have learned the hard way. 12 ft-lb of torque on camshaft cap bolts is too much torque and a ft-lb torque wrench is not an appropriate tool for the job.

OK I am sure there are a lot of wrenchers out there that have been successful at 12 ft-lbs and with a ft-lb torque wrench but from two very reliable and informed Kawasaki sources - the factory maunal overstates the necessary torque and a ft-lb torque wrench is as subtle an adjustment tool for the job as a sledge hammer.

So what is the problem? The steel camshaft cap bolts strip the threads out of the aluminum head. They come out like little curlicues. One of my sources who rebuilds Kawasaki engines said he has seen this at least 500 times. Personally, I misued my torque wrench and stripped out 6 of my 16 bolt bolt-holes. Yes I felt like an idiot - i was glad to hear I wasn't the only idiot that had ever done so.

Although the head and the camshaft caps are forged together there is a degree of play in the alignment. You can use "Time Serts" (like Helicoils but better) to re-establish proper size threads in the head - and done correctly are probably a lot stronger in holding power than the original threads. However, 90 in-lbs is all you need on the canshaft cap bolts.

If you have any concern about the camshaft cap bolts being stretched or at all messed up - get rid of them. This is another classic means of stripping the aluminum threads out. The stretched out threads of the bolt make easy work of wrecking the aluminum.

A couple of quick notes: Be careful when you turn the crankshaft for the first time after reinstalling the chain tensioner and before the chain has retightened. On my KZ1000P (2005 Police) the chain tensioner is a spring unit under the intake manifolds. The chain over the camshaft has a good bit of slack and as the chain tightens-up there is a tendency for the chain to come up and over one or more links as it takes up the slack. After all that work- the camshaft are not correctly aligned at TDC and you have to do it all over again (can you guess I speak from experience?)

After many days of fixing problems I made for myself I am ready to move on to what I started with - checking the valve clearance and tweaking the tune.

Kirk

Congratulations Kirk...you are now a member of the increasingly large club of Kawasaki enthusiasts who have screwed up camshaft cap bolts...many of whom not-so-coincidently frequent this forum Welcome to KZR.

Lots of folks have stripped the cam cap threads out, but I believe more KZ1000 / KZ1100 owners have done this than owners of KZ650 and some other models. The reason is that at least some of the KZ1000 / KZ1100 Kawasaki Service Manuals specify 12 foot pounds of torque while the KZ650 Kawasaki Service Manuals specify 95 - 113 inch pounds which is 7.9 - 9.4 foot pounds. That's a LOT less torque even though the cam cap bolts on the KZ1000 / KZ1100 are the same size (6mm x 1.0) as those on the KZ650. I don't know why the torque specs are so different.

Regarding the torque wrench use; wrenches calibrated in INCH pounds normally are more appropriate than those calibrated in FOOT pounds for small torque specs such as cam cap bolts. This is because mechanical torque wrenches are accurate from 20% to 100% of their full scale but should not be used below or above those limits (See www.cditorque.com/education.html#Safety ) So, as an example, if a torque wrench has a range marked 5 to 75 foot pounds since 20% of 75 foot pounds is 15 foot pounds the accuracy of any setting below 15 foot pounds is questionable. Ed

I've read about this so much and since I knew I was gonna have my cams out more than a few times (with stronger than stock springs) I went ahead and replaced all mine with heli coils before I sent it out for re working. Would have used time certs but since I was nervous about the job and had used heli's a few times I went with them. I still used only around 75 inch lbs if I remember right and they felt good and solid. Bought a quality beam type and a cheap clicker and they both seemed to match up very close in readings.

The torque wrench I used first was a 3/8 inch, 10 to 80 ft-lbs. A goliath for those cam-cap bolts. I now have a 1/4 inch 20 to 200 in-lb torque wrench - the right tool for the job.

I love it that Kawasaki gives 95 to 113 inch pounds spec on the KZ650 for the same bolts on the same type of head.

I got the camshafts back in and did the valve clearance tests. They were all in spec (most toward the higher end of spec) except intake on cylinder 1 which was just out of spec at .17 mm. Now I figured I could live with that but since I had gone through all that trouble, I might as well do things right and pop the shim and see what I had in my collection. I even have the Kawasaki shim tool.

How the heck does the shim tool work on cylinder 1 on the intake side? The side metal together with the camshaft design do not allow you to position the shim tool so that the cam lobe won't hit it when it is coming around off the shim and tappet. You can't move it far enough right or left, out of the way of the cam lobe as it comes around. I gave up but I was not about to take the whole thing apart again - I will live with .17mm on the intake on cylinder 1 at least until next time.

Any one make the tool work or have a work around?

keconomos@sbcglobal.net wrote: The torque wrench I used first was a 3/8 inch, 10 to 80 ft-lbs. A goliath for those cam-cap bolts. I now have a 1/4 inch 20 to 200 in-lb torque wrench - the right tool for the job.

I love it that Kawasaki gives 95 to 113 inch pounds spec on the KZ650 for the same bolts on the same type of head.

I got the camshafts back in and did the valve clearance tests. They were all in spec (most toward the higher end of spec) except intake on cylinder 1 which was just out of spec at .17 mm. Now I figured I could live with that but since I had gone through all that trouble, I might as well do things right and pop the shim and see what I had in my collection. I even have the Kawasaki shim tool.

How the heck does the shim tool work on cylinder 1 on the intake side? The side metal together with the camshaft design do not allow you to position the shim tool so that the cam lobe won't hit it when it is coming around off the shim and tappet. You can't move it far enough right or left, out of the way of the cam lobe as it comes around. I gave up but I was not about to take the whole thing apart again - I will live with .17mm on the intake on cylinder 1 at least until next time.

Any one make the tool work or have a work around?

Harbor freight sells a 200 inch-pound wrench that is about right for torqueing 100 IP. I usually use 100 IP as the limit.

Just nip them up by hand with a 10mm spanner and a drop of thread lock.

keconomos@sbcglobal.net wrote:
Any one make the tool work or have a work around?

There is a write-up on a GS site that has been liked to a couple of times here. Basically, you rotate the crank until the valve in question is fully open. Stick a heavy zip tie in the sparkplug hole so that the end of it will be on top of the open valve. Slowly rotate the engine until the cam lobe on that valve is pointing directly away from the valve. If done right, the zip tie will keep the valve open far enough to remove and replace the shim. When the new shim is in, rotate the engine back just enough to release the zip tie.

Hi ZED1015,

I've talked to a number of experts including a factory rep that trains Kawasaki mechanics. Doing them to 90 inch pounds with an inch pound torque wrench and a dot of blue thread lock is highly preferred over the "give it a nip with 10 mm spanner" method.

Now, you may be the wrench whisperer, in which case it is all well and good for you but for me and I am sure a lot of other not so psychic wrenchers - I think I should stick with a torque wrench.

Kirk

HI TEXASKZ,

THAT IS CERTAINLY AN INTERESTING POST. I simply can not form any kind of picture of what you describe and have no idea how that would work.
The shim resides in a circular depression in the tappet which is set below the camshaft on the top of the valve head at the top of the engine. The spark plug hole is 7 seven inches below in the cylinder head.

A cable tie?

keconomos@sbcglobal.net wrote: Hi ZED1015,

I've talked to a number of experts including a factory rep that trains Kawasaki mechanics. Doing them to 90 inch pounds with an inch pound torque wrench and a dot of blue thread lock is highly preferred over the "give it a nip with 10 mm spanner" method.

Now, you may be the wrench whisperer, in which case it is all well and good for you but for me and I am sure a lot of other not so psychic wrenchers - I think I should stick with a torque wrench.

Kirk

Tiss true! I am the wrench whisperer and also a trained motorcycle and Kawasaki race mechanic of over 40 years.
When these were new it was all well and good just bolting them down with a torque wrench but unless they have been helicoiled you have more than a 50/50 chance of stripping them out at the prescribed torque given the age of the alloy.
8lb and a spot of Loctite is all that is needed and any experienced mechanic will achieve that by hand.

The zip tie method is an old race track trick ( also thick string in the pre zip tie days)
Looped around the valve through the plug hole it gets trapped between the valve and seat holding the valve open enough when the cam is rotated out of the way to remove the shim without resorting to the shim tool.
The soft plastic of the tie does not damage the valve or seat.

Hi Zed,

Operative words "experienced mechanic" - you are a pro and I am a novice. I don't know, what I don't know so I don't have the luxury of knowing where I can relax and where I can't. Even when I dot my i's and cross my t's I still cause myself a world of headaches way too often. I am not really complaining because that's where I get the experience and I am patient man and quick learner.

I now get the concept of the cable ties - they go in the spark plug hole and somehow get between the valve and the valve seat while the valve is down, Then the valve is kept from going back up by the cable tie plastic when the cam lobe is rotated out of the way. Since I've figured out what you're talking about I haven't looked at my bike - but it seems to me the spark plug holes are almost vertical (on my kz1000P) and a little bigger than my pinky finger in diameter. Can you actually see the lowered valve and the space between the valve and valve seat through the spark plug hole?

Thanks for the input.

Kirk