Cam cap bolts stripped

First thing I did before I sent my head out was replace all 16 holes with heli coils.....m6 by 1.0. Checking with (2) new inch/lb wrenches what I was getting them at by hand with a 3 and a half inch long wrench by hand for years was right around 65 inch lbs or so and never had a problem with stripping or one backing out.

I knew I was gonna remove and replace them alot with checking the 750 cams with plexigage, bench shimming the head and getting the clearance right at 100, 500 and 1,500 miles. Used 65 inch/lbs this time then did a hair more with the wrench and they felt perfect to me. I also used a trace of anti seize on the bolts as I have heard heli coils sometimes like to back out when removing the bolts and am hoping this might help to stop that. NOT! saying that is the right thing to do just seems logical to me.

Using vice grips like shown to seat the cam down into the bearing saddles will greatly reduce stress on the threads. I like to use TWO sets of vice grips per cam but you get the idea (the attached photo is from the Suzuki GS850 manual). Using the caps and threads to seat the cams against the valve springs puts a lot of stress on the threads and should be avoided.

vice grips by nessism , on Flickr

zed1015 wrote: Don't torque them.
Just nip them up by hand with a 10mm spanner and a smear of non permanent Loctite on the threads.

Absolutely my take on any 6mm fastener, not always with the thread locker (case covers, cam cover etc dont need thread lock)

Also something to think about is generally torque specs are given for dry threads. If torqing oiled threads normally recommended to reduce torque 25% or so. Of course the camcap bolts will always be oiled so are the Kawasaki spec torque values accounting for oiled threads or not I wonder? 105 in/lb is pressing the limits of a 6mm bolt even dry, wile oiled is stretching another 25%. Seems to me reduce the 25% for oiled threads from the 105 in/lb and that is 75 in/lb or so. Less worry. No one in the motorcycle world has ever had a camcap bolt work itself loose that I've heard of.

Solid point mate, is this why everyone is always asking for torque tables?

found this while rummaging for information.

kzrider.com/articles/technical-tips/36-setting-valve-clearances - " It is a great idea to torque the cam cap bolts prior to making clearance measurements. In the event any are not torqued properly, the measurement you make WILL be WRONG!!! The early cylinder head is about 9 lbs. and the later is about 12 lbs. Consult a torque table in your manual for all torque specifications."

what are your thoughts?

The writer makes the point ot say earlier years have a M6 and later years has M8, 1973-80 respectivley, but i can tell you my 82 kz550c has M6 threads. and I blew a thread before i reached 90 in/lbs. which probably means the person before me overtorqued and i got left with crummy threads.

I haven't used a inch pound torque wrench in years. I go by the feel. If I'm loosing a bolt I can tell if it is seizing. I'll turn it back in then out a few times until it loosens up in the threads. Sometimes it can't be helped. I have #6 Heli Coils on hand just in case.
Steve

Whats your opinion on re-threading the whole lot, just to start fresh? I mean im gonna have to spend the 60 bucks to fix the one thread.

Nessism wrote:

Kz_Café wrote: I e heard and read anything from 65-145in lbs. the 145 was the original manufacture torque. Are they not like engine head bolts? Where it's important to reach the full ft/lbs? IE: if I hit somewhere comfortable between 65-100inlbs I'm not gonna worry about bolts backing out?

The factory Kawasaki service manual clearly states 105 in-lbs.

And that would be an absolute maximum. You need an accurate torque wrench to make sure if you are going to go for the limit. I have a 200 I-P (max range) wrench I use but I don't go above 100 IP when I do it.

Kz_Café wrote: Whats your opinion on re-threading the whole lot, just to start fresh? I mean im gonna have to spend the 60 bucks to fix the one thread.

I wouldn't. The inserts aren't cheap ether. I'd keep them on hand. I'm going to pick up some more before I do my valve adjustment in a week or so. I think I'd replaced 5 in this head. There will be more I'm sure.
Steve

Kz_Café wrote: found this while rummaging for information.

kzrider.com/articles/technical-tips/36-setting-valve-clearances - " It is a great idea to torque the cam cap bolts prior to making clearance measurements. In the event any are not torqued properly, the measurement you make WILL be WRONG!!! The early cylinder head is about 9 lbs. and the later is about 12 lbs. Consult a torque table in your manual for all torque specifications."

what are your thoughts?

The writer makes the point ot say earlier years have a M6 and later years has M8, 1973-80 respectivley, but i can tell you my 82 kz550c has M6 threads. and I blew a thread before i reached 90 in/lbs. which probably means the person before me overtorqued and i got left with crummy threads.

While I was bench shimming mine after moving the cams a few times I wondered if I needed to go all the way to 70-75 inch/lbs for a accurate reading so I tryed a few at 30 and 40 inch/lbs then went to 70 and could not measure a difference.....but still did them all at 70 just to be sure........like I said I went ahead and re did all mine at once so I didn't have to worry about them later and if I remember right the kit I bought had 20 inserts so I was all set.

Mine come in a pack of 5 at Fastenal.
Steve