2011 CBR250R Torque Specs

g_will said:

I recently got the bike second hand and it needs some fixing. I'm replacing the fuel tank and pump assembly as they were destroyed due to corrosion but I don't know the torque specs for the tank bolts. I don't have the service manual, only the owners and I didn't see it in there.

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In the service manual there is no information for the tightening torque of the three fuel tank screws. There is a tightening torque to the 6-Nuts that attach the fuel pump to the fuel tank: 12Nm
If you're going to take care of your motorcycle buy yourself the right literature, the Honda book, and the Haynes book, it's a worthwhile investment.

Torque wrench is nothing more than a nice toy for a mechanic who can afford a good set of a few of these according to the various tightening values. A torque wrench can not prevent a certain cases of over-tightening or under tightening, its handle is large and it does not allow the appropriate feeling that needed for stopping over tightening. A mechanical torque wrench is not an automatic tool, the requirement must be entered into it, and the requirements differ from screw to screw and the tightening of one screw in the torque of another screw will also end badly.
Additionally, the tightening torques for the same thread, say the very common M6 from our motorcycle, is affected by many factors:
1. Screw strength (Some screws have different strengths).
2. Diameter of screw head(With or without flange).
3. With or without lubrication.
4. Thread material (metal, aluminum, or plastic).
5. With or without thread-lock. And the strength of the adhesive, usually medium strength ("blue").
6. A worn screw or worn thread is easier to destroy.
The bottom line: Every beginner amateur mechanic should buy himself some screws and nuts and start to destroying them until he understands and mostly feels what is that "feeling" of true tightening value. you should learn to feel the flexibility of the metal, when to reach the stopping point, and not to use a lever that is too long which reduces the feeling.

DannoXYZ said:

Well, it's been proven over and over again that expert pro mechanics will over-tighten small fasteners and under-tighten big bolts when going "by feel". Even after decades of experience they can't get better than +/-10%. We don't aim rockets "by eye", but rely on instruments with much, much more precision than our senses allow.

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Yes BUT...
What you explain is beautiful for professionals, and I wrote about the variety of parameters that make amateurs fail even with putting in their hands the most accurate NASA devices.

Being close to the right point is a standard value that will not cause failure, being far from the right point will cause destruction. Some of the devices, especially the cheap ones, also have similar accuracy percentages. Whoever has the "right feeling" his chance of causing damage is almost non-existent. When did NASA send missiles to the moon with a half-worn screw? In the cases of old motorcycle mechanics there are threads that can be used or extended for life if the tightening torque is reduced.
At NASA every gram of weight is calculated, so each missile screw is designed exactly according to the exact load it has to take, in motorcycles most of the screws are much stronger than they should be.

Spaceships fail because mechanics acted only by the book, my friend, there is no substitute for common sense or "by feel".

When possible use both. Not every amateur mechanic has a budget to buy the devices, and not every amateur mechanic will make proper use with the devices. There is no substitute for "by feel"-"tools", and to this it can be added the instrumentation capabilities.

Anyone who only relies on the capabilities of the device has not bought himself any real confidence in the proper tightening of screws.

DannoXYZ
So far I have found in the Honda-service-manual two mistakes. It's clear to you that there can be mistakes in that book, yes? Maybe also errors in the torque values? Therefore there is no substitute for this thing called professionalism and expertise or "by feeling tool".

Update - Three "mistakes"
I remembered another case, this time a case of a problem I was has with the torque: