stupid question

[Guest]

Hi guys and gals.

I seem to have lost my nuts. The ones that fits my turn signals, that is. What size do I need to pick up?

The bike is a 1979 GS850G.

Remember: There is no such thing as stupid questions - only easy answers

thanks!

 

[Burque73]

I could dig one out of a box but don't know how to tell you what size it is.

I just printed this chart. Let me look around for the nut.

 

[Burque73]

ok, inside diameter with calipers measures 8.7mm (8mm) outside =13.86 (13mm) pitch 1.25

These are from an 81 850 G

Hope it helps you.

 

[bwringer]

The nuts are 10mm thread, 1.25 thread pitch.

Original width (wrench size) is 14mm, but most nuts you'll find in hardware stores are 17mm. (Japanese and Euro/US metric standards are different.) These should work OK in this application -- just make sure you get the correct 1.25mm (sometimes called "fine") thread pitch.

 

[Burque73]

The nuts are 10mm thread, 1.25 thread pitch.

Original width (wrench size) is 14mm, but most nuts you'll find in hardware stores are 17mm. (Japanese and Euro/US metric standards are different.) These should work OK in this application -- just make sure you get the correct 1.25mm (sometimes called "fine") thread pitch.

So, different part for that year, inaccurate measurements from me, or maybe mine was an aftermarket item?

In any case, thanks for chiming in.

 

[Guest]

Many thanks guys! I will try my luck in the nearest hardware shop.

This is a fantastic forum BTW!

 

[bwringer]

So, different part for that year, inaccurate measurements from me, or maybe mine was an aftermarket item?

In any case, thanks for chiming in.

You had the right nut and you measured pretty accurately; you just interpreted the results incorrectly.

1) You measured the inside diameter of the threads. Threads are specified by their outside diameter, AKA the "major diameter" (basically, measure the outside of a bolt, not the inside of a nut). So your measurement was reasonably accurate, but you measured the minor diameter. (More info.)

2) You measured the outside of the nut fairly accurately as well; you just rounded the wrong way. Nuts are made slightly undersize so a wrench will slip into place easily, so a measurement around 13.9mm would mean you use a 14mm wrench.

3) Japanese vehicles (and Korean and other Asian vehicles FWIW) use JIS (Japanese Industrial Standard) fasteners, so if you know these standards and how they differ from US & Euro standards, it's pretty easy to know what fastener sizes and thread pitches you are working with.
M6-1.00, 10mm wrench (same as US/SAE and European/DIN metric) Sometimes you see decorative versions of M6 fasteners like case bolts with M8 wrench size heads.
M8-1.25, 12mm wrench (SAE/DIN use same thread but 13mm wrench)
M10-1.25, 14mm wrench (SAE/DIN use 1.50mm pitch, 17mm wrench)

There are various exceptions and special cases, (for example GS brake banjo bolts are M10-1.00 thread, most other bikes use M10-1.25), but generally just bear in mind that JIS fasteners are usually a little different and verify all dimensions before you buy a substitute. Hardware stores in the US and Europe stock mostly SAE/DIN metric stuff, and most have little to no true JIS hardware. I don't know why -- Japanese vehicles are extremely common everywhere, but it's still ridiculously tough to find the right fasteners sometimes. That's another rant for another day...

Sometimes you can substitute, sometimes not. For example, there are many places where a 10mmX1.25 nut with a 17mm wrench size (SAE/DIN fine thread) won't fit, so you have to locate a JIS nut with the correct 14mm wrench size. Other times, such as turn signals, a bigger nut isn't usually a problem.