How to measure exhaust size?

[Saint aka ML]

So I have a termi system for 999 and one for monster.

How do I find out pipe diameter?

When they size 57mm size do they mean internal or external diameter?

[slob]

Outside (technically tube not pipe)
I suspect you'll find it's actually 57.15mm, which is 2 1/4"
Remember you need to measure a straight bit, as it'll be mishaped around any radiuses

Stock monster is 45mm (1 3/4")

[utopia]

And it costs thirty bob a foot.

:D

[Dirty]

http://www.microntesa.co.za/images/standard-gage/vernier_calipers2.jpg

[Saint aka ML]

Lol so it seems I got headers and half of system on 999 in addition to what is fitted. It is titanium lol.

Need to weld one pipe and will hopefully have full ti system if all fits