Any question answered...

I need to install some protective bars on my motorbike. They protect the engine / oil carters and things like that when the motorbike fall. I bought them on ebay a long time ago, and never installed them as one of the fixing points is on a threaded rod that attached the engine to the bike frame. When the protective bar's plate is on, there not enough thread anymore to fit the bolt. So I need a longer threaded rod.

There are three options for M10 bolts - standard pitch (1.5mm pitch), fine (1.25mm pitch) and the other really fine fine (1mm pitch). You'll need to know which one it is before buying the bolt. The easiest way to work it out is to take the bolt out, and measure 10 threads. In my experience most Japanese engine bolts (Honda Blackbird, ZX9R, R1) are M10x1.25.

Namrick is a useful place for buying bolts (www.namrick.co.uk) is a good place for buying small quantities of unusual bolts, although I don't think they do metric fine cap heads. You'll probably want a 12.9 spec bolt, which most cap head bolts will be.

What kind of bike is it? Might help narrow the options, as would some more information about what bolt head it has.