Head tube nuts

[erniebearskin]

Under the top clamp there is a weird nut with 4 slots, what is required torque for this and how does one torque it. After I install the top clamp the main top nut seems to have two different torques given in my manual, what is the required torque for this? 45 nM? Thanks everyone in advance for responses.

 

[gasgasman]

I don't torque mine.
I just snug it down to take out the slack in the steering stem bearings.
You want it tight enough that the handle bars "fall" over to either side with some friction.

 

[bowhunter007]

Once you use the preload nut(under the clamp), to take up the slop in the stem bearings. The "normal" nut on top of the clamp is what holds it all together. IMPORTANT: one affects the other. If the nut on top is too tight it will put too much preload on the bearings. Then you have to take it apart, and loosen the preload nut a tad and try again. A pain...yes, but worth the effort to get it right. I typically use loc-tite & tighten by hand(top nut). It's very easy to overtorque, so be careful. 33 ft lb of torque should be plenty(so my manual says).

 

[Jakobi]

On Yamahas the torque on that nut is 7NM.

As above, you want it just tight enough to take the slop out. When you torque the top nut on the triples everything pulls together much more. I usually do a couple of runs until it feels just right. So the bars sit straight but gently fall to the side if bumped.

 

[Neil E.]

Think about the few thou of play in a thread. You snug the bottom nut down and it sits with it's threads UP against the stem threads. Now you put the upper nut on and tighten it. It pushes the lower nut down (paired locknuts always push themselves apart to lock).

So as they push apart the lower nut is putting more force on the stem bearings, tightening them up. That is why you have to start out with the lower one looser to allow for the movement due to thread play.