This is the Japanese parts catalog for searching for part numbers.  Click the blue button on the bottom of the page then make the appropriate choices of model and year.  (Click the categories and you'll see the model numbers and what-not.)

http://www.yamaha-motor.co.jp/parts-search/

部品情報検索（パーツカタログ）

Turns out they have a great application for the iPhone as well! It's called Yamaha Parts Catalogue. I downloaded it today. It's in Japanese, but there may be an English version as well. Check it out!!

iPhone用のヤマハ・パーツ・カタログ（Yamaha Parts Catalogue）ってアップリ発見！今日、バイクを組み立てたとき役に立った！是非見てご覧。

Just found a great site that has the parts schematics and part numbers in English.  This should really help out all you guys in Australia and New Zealand when looking for parts.  May also be able to be used to try to find matching part numbers between models.

The site is called: Impex Japan

Hi and thanks for this useful information.

Another site that offers plenty of information in English is megazip.net, the specific link to Yamaha SRV250 is:
https://www.megazip.net/zapchasti-dlya-m...v250-19267

Cheers, 

Jorge