Installing engine guards/crash bars: proper bolt torque? F750gs

I'm planning to install some crash bars/engine guards on the F750, and the instruction manuals I'm finding aren't listing what torque to tighten the bolts to, particular the upper bolts that use the engine mounts. I've tried checking the instruction manuals for a few different brands of bars, and at best they just say to use the factory torque spec (as they are reusing a factory bolt).

What are others doing for this? It seems I can't buy a paper or digital copy of the service manual.

I don’t get too worried about torque in installs such as this…..more of a “mechanics feel” kinda deal.

This thread- https://forums.bmwmoa.org/showthread.php?98226-K75s-Maintenance and the associated links may help you.

OM

Omega Man said:

I don’t get too worried about torque in installs such as this…..more of a “mechanics feel” kinda deal.

This thread- https://forums.bmwmoa.org/showthread.php?98226-K75s-Maintenance and the associated links may help you.

OM

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I figured the torque numbers for the fasteners that just go into the engine block didn't need to be too specific, but I thought the upper engine mount bolts might need to be tightened to something particular, and might need to be tightened in a particular sequence. I saw something about a bushing in the upper engine mounts and thought maybe the torque amount here was to set a proper amount of "squish".

Should I use thread locker on the engine mount bolts?

Usually if I take something apart and there is thread locker, I will use it again. Sometimes I will wonder and use Nail-Polish as a semi-thread lock compound.
Perhaps you can post up the brand of bars you are looking to install and one of the group here can be more helpful in digging up more information.
OM

Omega Man said:

Usually if I take something apart and there is thread locker, I will use it again. Sometimes I will wonder and use Nail-Polish as a semi-thread lock compound.
Perhaps you can post up the brand of bars you are looking to install and one of the group here can be more helpful in digging up more information.
OM

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The bars I'm looking at are Outback Motortek, but pretty much all of the brands of bars I've looked at use the upper engine mount bolts in some way (some, like Givi, are a single set of bars that mount down on the engine, and then up on the upper mount, others have an upper and lower set of bars where the uppers use these mounts, such as the factory BMW bars, Wunderlich, Hepco & Becker, Touratech).

From Touratech-

https://touratech-usa.com/store/Engine-Crash-Bars-BMW-F850GS-F750GS

https://cdn.touratech-usa.com/09-082-5160-2.pdf

Looks like they are using "generic" torque specs.

The Outback Motortek bars look good- https://east.outbackmotortek.us/product/bmw-f700gs-f800gs-crash-bars/

Their installation instructions are similar to the TT bars in that they give the "generic" bolt torque settings-

https://east.outbackmotortek.us/wp-...-F800GS-Lower-Crash-Bars-PDF-installation.pdf

They seem to be interested in helping with questions. Perhaps a call will clarify your concerns?

OM

Omega Man said:

From Touratech-

https://touratech-usa.com/store/Engine-Crash-Bars-BMW-F850GS-F750GS

https://cdn.touratech-usa.com/09-082-5160-2.pdf

Looks like they are using "generic" torque specs.

The Outback Motortek bars look good- https://east.outbackmotortek.us/product/bmw-f700gs-f800gs-crash-bars/

Their installation instructions are similar to the TT bars in that they give the "generic" bolt torque settings-

https://east.outbackmotortek.us/wp-...-F800GS-Lower-Crash-Bars-PDF-installation.pdf

They seem to be interested in helping with questions. Perhaps a call will clarify your concerns?

OM

Click to expand...

The Touratech upper crash bar is using the engine mounts:

https://touratech-usa.com/store/Upper-Crash-Bars-BMW-F850GS-F750GS

Those instructions:

https://cdn.touratech-usa.com/09-082-5161-2.pdf

Are numbering them as bolts 3 and 7, and says they are M12 bolts. I'm not sure if they are going into steel or aluminum; they go through the frame, and I know there is a bushing in there, but I don't know if they thread into the aluminum of the engine case directly, or if they thread into some sort of steel bracket or mount that is attached to the engine.

I can reach out to Outback again next week, but was hoping to install the bars this weekend. They provided torque values for the 'added' bolts in their kit, but for those upper engine mounts they have you remove the factory bolt, then reuse it through their bracket, and their initial response was to tighten it to the factory torque spec. (The instructions you linked to are for the F700 GS bars, which mount differently and don't use that upper engine mount).

It is a bit surprising to me that it is so hard to find out what the factory recommended torque value is; and for that matter it looks like even the BMW accessory engine guards don't come with instructions with that info (and instead you are supposed to have a dealer install them).

If anyone stumbles on this looking for the spec, I was able to convince a BMW dealership to look it up for me over the phone, and they gave a spec of 100 nm for the engine mount bolts.

They also told me that they can't order me a service manual in any form (paper, CD, DVD).