Proper bolt torque

[Ost85vmax]

So I have a question that hopefully can benefit myself and others. I would assume that everyone doing maintenence on there bike does always torque every bolt as spec'd and possibly more often torques to what they feel is correct? Maybe I am wrong but I have done quite a bit and am going to buy a torque wrench tomorrow to have on hand. My question is, does someone with some experience want to comment as to the most important bolts to torque correctly maybe a short list from most important to least.

Thanks

Eric

 

[one2dmax]

Internal engine bolts (crank/rods/pistons, and case halves). The rest I do by feel.

Sean

 

[[email protected]]

Anything in the motor (rod bolts, crank mains, cam caps, head bolts....all that kind of stuff is critical.

I also torque rotor bolts, caliper bolts, engine mounts, frame sliders...lots of stuff I guess

Axles are done by "feels right" as are swingarm bearings and steering bearings.

I don't bother torquing anything with a phillips head, fender bolts, handle bar controls, etc. Whatever won't cause catastrophic failure if it falls off.

 

[AMechEng]

Torque specs are pretty important if the bolt has a clamping force like rod bolts or for mains caps. By torquing a bolt so that it approaches it's yield stress, it reduces the effects of fatigue, which must always be considered in high cycle applications. For most bolts I just torque by feel and use blue thread locker so that I don't worry about vibration loosening the bolt or screw.

 

[MaxMidnight]

So ...does someone with some experience want to comment as to the most important bolts to torque correctly..

If the fastener is too loose the part could falls off, too tight and you run the risk of stripping the thread or damaging the component.

Therefore on the basis that bolts are there to hold something on then surely they all must be important?

 

[naughtyG]

Whenever have a spec I use it. It's actually taught me that I was overtightening many bolts (especially smaller ones) when doing it by hand, so it's a good learning curve.

I find I often need both my torque wrenches, one for much smaller forces and one for the big stuff - the small one's more accurate but can't reach big torque, while the larger one does the big bolts but is useless at small increments.

 

[dannymax]

+1 Everything with a torque spec gets torqued to spec! unk:

 

[jfeagins]

The most critical nut on my 85 & 09 is the nut that holds the handlebars. It is subject to getting torqued off & on throughout any ride. The thing that'll torque it off the most would be a group of slow-moving HD riders on a very twisty roadway that won't move over to be passed. Next would be an inconsiderate driver or rider coming too wide through a corner, and over into the wrong lane.

Other than that, I've been known to use a torque wrench while installing new clutch plates.

 

[dannymax]

The most critical nut on my 85 & 09 is the nut that holds the handlebars. It is subject to getting torqued off & on throughout any ride. The thing that'll torque it off the most would be a group of slow-moving HD riders on a very twisty roadway that won't move over to be passed. Next would be an inconsiderate driver or rider coming too wide through a corner, and over into the wrong lane.

Other than that, I've been known to use a torque wrench while installing new clutch plates.

There would be some serious 'torqueage' going on if you ever rode around here....NOBODY stays in their own lane....it's friggin' crazy! That and the tail gateing can make even this mild mannered Irishman a little 'torqued'! :biglaugh:

 

[Ost85vmax]

Thanks all for the info! I think I shall still get me a torque wrench and dable with it for a while. Suppose if anything it will get my "feel" down a little better to what it should be and maybe nexy time I wont break off that damn clutch spring bolt again! Thanks.

 

[jfeagins]

I think Mother Yamaha must have used shiny peanut butter to make their OEM clutch spring bolts - it don't take much to twist one off for sure. When I did my '09, I simply went to the hardware store and bought hardened ones before attempting reassembly. But I still used the torque wrench so as not to damage the basket threads.

 

[m-cman]

You are going to need at least 2 torque wrench's. I have three to cover almost all values. The most important is the inch-pound version for the small torque values. I used to regularly strip aluminum threads in the early days but have had an inch-pound wrench since the the 70's. A quality one, not Harbor Freight! Then the middle range one for a 3/8" socket which is also used regularly. I also have a HD one for 1/2" sockets but don't usually need it on a bike. Used most often for truck lug nuts.

I am a firm believer in torque wrench's as I don't trust my "feel". :biglaugh:

 

[Redbone]

So all this discussion about using the proper torque setting, what torque wrench (Brand/ where to purchase) do you use for the light torque settings? For the heavier Torque settings?

 

[jfeagins]

Mine is a Craftsman 3/8" drive digital. It goes down to around 6.5ftlbs.

 

[[email protected]]

So all this discussion about using the proper torque setting, what torque wrench (Brand/ where to purchase) do you use for the light torque settings? For the heavier Torque settings?

I've got a couple. Both craftsman.

1/2 drive that goes up to around 150 ft lbs. It is a "click type". You unlock the handle and twist it till the indicator lines up with the value you want to use. There is a metric and standard scale engraved in the handle. I don't use this one too much.

3/8 drive that is also a click type. Its 15+ years old. This one has a knob on the end of the handle. Pull the knob out and twist it. It has two windows built in the handle with a moving scale in each window. One window shows metric, the other standard. It starts at about 6 ft lbs and goes up to around 70 IIRC. This one is used 99% of the time.