Quick ? Please help!

[sprtrx300ex]

What size is the large allen bolt on the left side of the engine. I need to adjust my valves and I need to know what size it is so I can buy one. Thanks

[PHIL_B54]

400ex???
if you buy the set it is the largest one, you will also need a smaller one to open the plug that covers the timing mark. so just buy the set, you will always use them somewhere