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Specific Torque?

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Hey guys,

 

I just got my first bike, it's a crf250r, but before I can get it on the dirt I need to change the oil and tubes and such. On the manual for the bike it says to tighten nuts to a specific torque. Is that necessary? Or can I just use a regular wrench and tighten it as much as i can?

 

Thanks, Mel

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Buy the torque wrench. You can go by feel on the oil drain bolts and axles and stuff but a torque wrench is a good idea for parts like triple and pretty much mandatory if you ever have to do the valves. If you are not comftorable with knowing how tight is too tight and how tight is not tight enough I'd get the torque wrench and torque everything. 

 

Pulling threads because you overtightened can be a real headache and/or expensive.

Edited by imbackmkay

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If using a torque wrench you must use a good quality 1/4 inch drive one. A 1/2 wrench is too big, and will do expensive damage quickly. Aluminum is very soft an strips easily. If doing it by hand, bolts just need to be snug, not "as much as I can"

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I'd go with a 3/8" I've got a 10ft/lb-100ft/lb SK and it it works for 95% of bolts on my bike.

 

Don't cheap out either plan to spend around 100 for a good one.

Edited by imbackmkay

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3/8 is too big. Torque wrenches are quite inaccurate at the lower and upper limits of their ranges. There are plenty of bolts on this bike with specified torques of less than 10ft/lb.

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3/8 is too big. Torque wrenches are quite inaccurate at the lower and upper limits of their ranges. There are plenty of bolts on this bike with specified torques of less than 10ft/lb

If you're gonna torque everything you really need both. Most bolts that are important to torque are over 10 ft lbs (suspension, triple clamps, the entire top end minus the valve cover). I don't bother with all the 6mm bolts with lower torque specs simply because it's overkill (imo)

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If using a torque wrench you must use a good quality 1/4 inch drive one. A 1/2 wrench is too big, and will do expensive damage quickly. Aluminum is very soft an strips easily. If doing it by hand, bolts just need to be snug, not "as much as I can"

For MOST general stuff I use good quality 1/4" drive socket set, short extension, 8mm,10mm & 12mm sockets and open/boxed end wrenches and snug is better than snapping the bolt.

As well, I use a LITTLE anti-seize on most steel bolts that go into aluminum. My Clymer is then specific as to where you need to use lock-tite.

I recently asked my local bike shop guy what he uses for a torque wrench. He tells me he uses a good t-handle wrench set and tighen's by feel or for example gets the bolt just snug, just barely seated, then 1/8 or 1/4 turn. He's been doing this for years so.......

When I look at the General Maintenance torque specs in my manual, it gives them in N*m (First and most complete), in-lb (2nd and covers most), & ft-lb (3rd for large bolts/nuts).

For example..

Spokes - 3.8 N*m or 32.7 in-lb

Oil Drain Bolt - 22 N*m or no in-lb or 16 ft-lb

Rear Axle - 127 N*m or 94 ft-lb - I use a good quality open/box end wrench for this.

When you start getting into Clutch Torque specs for it looks like a 3/8" or 1/2" drive in-lb or ft-lb wrench would be better

So my take is ideally you would have a 1/4" N*m torque wrench for things up to 25 N*m, then a 1/2" ft-lb for torque wrench for things above 25 N*m.

This is more than slightly confusing and then if you start adding in torque adapters or extensions, you start getting into math

Using this a 10 to 100 ft-lb wrench only gets you down to 13.5 N*m which would over tighten a lot of the clutch bolts.

http://www.unitconversion.org/energy/newton-meters-to-foot-pounds-conversion.html

I'd be interested to hear if there's an ideal cost effective solution to this if you really want to have a torque wrench or wrenches to cover everything.

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If using a torque wrench you must use a good quality 1/4 inch drive one. A 1/2 wrench is too big, and will do expensive damage quickly. Aluminum is very soft an strips easily. If doing it by hand, bolts just need to be snug, not "as much as I can"

He is right. I cracked an aluminum intake on a Buick using to big a torque wrench once

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