Handlebar clamp - torque procedure?

[metroplex]

I have a 696 and plan to replace the handlebar. The factory service manual is very vague on the torque procedure/pattern for the 4 bolts holding the clamp. Does anyone know the proper order of tightening those 4 bolts?

[Slide Panda]

Proper order is first one first, last one last.

It's not like a cylinder head where it's important. If you want to be 'safe' just to a star pattern. Top-left -> bottom-right -> top-right -> bottom-left

[metroplex]

The reason I ask is that I noticed if I torqued the top bolt first, then the clamp gets oriented towards the top and there's uneven torque. If I torqued the bottom bolt first, the clamp favors that side. Etc... I forgot exactly which way I went to solve this issue, but it seems like if I didn't follow a certain pattern some of the bolts would never torque properly.

[Howie]

Tighten down evenly in a cross pattern to snug, then torque in a cross pattern.

[Speeddog]

The 696 clamp is asymmetrical, like many bar clamps.

The 2 bolts that the "arrows' point to (rear ones, in this case) are to be torqued fully, with the other 2 (front) bolts loose.

Then do a  back and forth torquing of the fronts.

It's a stronger assembly when it's done that way.

[metroplex]

Speeddog, thank you!

[Howie]

DOH!  Kudos to Nick!

I should have realized that.  Though I knew the clamp is asymmetrical the proper sequence never dawned on me.  I don't think it is critical, but correct is correct

[ungeheuer]

As with everything, just tighten the bolts 'til they go loose and then back a half turn 

[The Bearded Duc]

As with everything, just tighten the bolts 'til they go loose and then back a half turn 

Tried this on a rearset mounting bolt on the 750 a while back, worked like a charm!   

[metroplex]

I'm German when it comes to torque specs and procedures, its just that the Ducati factory service manual is extremely vague when it comes to certain procedures. For instance, it says 25 N-m, use grease B (ok I get all of these things), 1-2-3-4. What exactly does 1-2-3-4 mean? In addition, Ducati does not include the torque specs in the actual procedures. They have a wonderful electronic service manual with color photographs - but they then tell you to refer to the torque spec sheet versus pointing out the torque spec for each bolt. Ford has a crappy service manual format, but they at least indicate the torque spec for each fastener on the same page.

I think through trial and error I did what Speeddog suggested and I didn't write it down in my notes.

[suzyj]

I'm German when it comes to torque specs and procedures, its just that the Ducati factory service manual is extremely vague when it comes to certain procedures. For instance, it says 25 N-m, use grease B (ok I get all of these things), 1-2-3-4. What exactly does 1-2-3-4 mean? In addition, Ducati does not include the torque specs in the actual procedures. They have a wonderful electronic service manual with color photographs - but they then tell you to refer to the torque spec sheet versus pointing out the torque spec for each bolt. Ford has a crappy service manual format, but they at least indicate the torque spec for each fastener on the same page.

I think through trial and error I did what Speeddog suggested and I didn't write it down in my notes.

Do them up tight enough that they don't fall out, but not so tight you rip their heads off.

There are like half a dozen bolts on my whole bike (excluding stuff inside the engine) that I break a torque wrench out for.

Oh, and being able to judge what torque a given fastener needs, and what torque you're applying, is like mechanics 101.  You might as well have asked what direction to turn the bolts in.

[He Man]

As with everything, just tighten the bolts 'til they go loose and then back a half turn 

how do you tighten till loose?

and what's the torque procedure for that?

[Ddan]

how do you tighten till loose?

and what's the torque procedure for that?

You'll figure it out.  Try it, it works.   

[metroplex]

Oh, and being able to judge what torque a given fastener needs, and what torque you're applying, is like mechanics 101.  You might as well have asked what direction to turn the bolts in.

I have to disagree, maybe because I am an engineer that also enjoys mechanics. For one, Ducati marked the 25 N-m for the handlebar clamp bolts as "*dynamic safety-critical point; tightening torque must be within Nm ±5%." I normally follow the torque spec for my cars and engines, so I don't make an exception for my Ducati especially when it is marked by Ducati as "dynamic safety-critical point."

Second, different fasteners have different torque requirements based on the grade, material, and application. The only time I estimate the torque is if I am able to look up the recommended torque for a bolt spec (thread pitch, material, length, grade) similar to the one at hand that doesn't have a spec listed in the service manual. I've worked on cars for well over 13 years and always refer to the torque spec in the FSM. I even look up the torque values for fasteners/bolts for my rifles if I am doing any work on them. FN Herstal provided a torque spec for the FN SCAR's barrel screws but they're only found in the Navy Operator's Manual and not the commercial owner's manual. The Army Marksmanship Unit even found that a certain torque value for the flash suppressor was required to prevent distortion the muzzle causing reduced precision.

Third, there are RH and LH threads. Ducati used a LH thread for one of the sideview mirror bolts, and one of the adjustment links on the gear shift, which is opposite of righty tighty, lefty loosy. The AK's (47, 74) traditionally uses a LH thread for the muzzle brake, and it still feels weird when I tighten by turning anti-clockwise on those threads.

It was just in this instance of the asymmetric handle bar clamp that there was a specific sequence, not a torque issue. If I torqued it out of sequence, some of the bolts wouldn't tighten properly.

[Howie]

Nothing wrong with doing things correctly.  It is also amazing what you can get away with.  I walked into a dealer one day.  The arrows on the handlebar clamps were facing the wrong way on a bunch of bikes.  I spoke to the service manager.  He told me I was wrong.  No complaints of bars loosening.  After insistence from me he called tech, came back and told me I am correct.

Back to torquing fasteners.  Experience gives you a pretty good feel, particularly on smaller fasteners.  In real life, there is often no room to use a torque wrench, particularly on cars.  Back when I worked on cars for a living I didn't use a torque wrench all that often, even on fancy German cars.  These days I use a torque wrench a lot more than I used to.  The feel is lost. 

Back in the days when i was working on BMWs there were two big paper manuals.  One was procedure, one was specs.  For the do it yourself or fix any car wrench, a pregnant dog.  For a product specific wrench, great system.