APE studs

Hey kz'ers got a question for ya. On my 900 i need to re-torque my head cause i got a small leak on the side between the head and cylinders.the motor has APE studs in it. My question is are the studs torqued to the same amount of foot-lbs as regular bolts or do they get torqued to a higher amount. and what is that namount. Thanks.

Are you torquing the studs or the head nuts?

head nuts

I don't believe it should matter what type of studs are installed. Below is a link to the torque specs for the 900 and 1000's.

kzrider.com/index.php?option=com_kunena&...d=2&id=317332#317433

It depends if you have both HD studs and the longer HD nuts... with both I have went as high as 55 FT LBS (race only engine)

With the nuts only and stock studs you should only be going to the recommended factory torque setting because the stock studs have a thinner diameter thru the middle section where as the HD version is thicker and made of better steel... the stock studs will strip out under high torque.

The HD nuts are stronger and won't crack under high torque loads, plus they are longer to make up for a milled deck or head so they won't bottom out on the stud end.

i use stock nuts and ape studs. 40 to 42 ft. lbs.

We recommend up to 44 lbs.

Jay..you forgot to mention that's with a good torque wrench :laugh:


Seriously..... I just had this discussion on Friday night with a guy at the track with a $9 Harbor Freight torque wrench. His head gasket is leaking and he swears it wouldn't take any torque after the rebuild.

Then he pulled out his HF torque wrench

So even with the O.E. head nuts you recommend increasing the amount of torque put to the head? Is this just because the studs were the weak component previously?

Make sure the stock nuts aren't bottoming out on the top of the studs. Sometimes the HD don't get seated as deep in the cases. I've seen this problem many times.

TerryK wrote:

Make sure the stock nuts aren't bottoming out on the top of the studs. Sometimes the HD don't get seated as deep in the cases. I've seen this problem many times.

Good point. thats why ape nuts have no top cap. they can be drawn down farther if u mill the head .
i actually had the opposite problem and needed to shim my studs up.
the stock studs are fine for a stock motor. the problem occurs with high compression pistons (motors ). the stock studs will stretch under load, so the ape studs are stronger to prevent stretching.

Actually our Kawasaki nuts do have a top on them, but we have designed them so it is impossibly to mill the head far enough to make these nuts bottom out on the stud.
That is why they are called "Tall Nutz"

kzzone.com/studs.html