We found one of these as part of a NOS (new old stock) sale:

You can sometimes find them on eBay US, eBay AU and CMSNL – it’s a Honda Special Tool, part number 07999-4150000:

The tool itself has a thread to be inserted in the inspection cover hole on the rear right hand side of your bike:

The glass/crystal looks like it is held in by adhesive:



Here’s where it goes – you’ll have either a breather bottle or a cover over the hole:

It should screw in easily:

…and give you a nice clear view of the timing marks as they spin past! If you do use one of these, make sure to put your bike on the side stand to decrease the amount of oil in this area…

For a closer look at other Honda Special Tools, check here! We will update with a video of what it looks like in action once we get the 650 motor spinning.