Trials machinery inspection scrutineering


This information is based on our Youtube video Pre-competition mechanical inspection and is subject to our disclaimer here.

When entering an observed trials competition, your trials bike will be subject to a machinery inspection (or scrutineering) to ensure it is safe to ride. For some events a self scrutineering form will need to be completed. Scrutineering form.  Make sure you bring along sufficient tools and parts to fix anything you missed in your pre-ride preparation (checklists further down the page).

The supplementary regulations for a moto-trials event will list the time scrutineering takes place prior to ride.

Most importantly, your trials bike must be fitted with a lanyard kill switch. The lanyard goes around your wrist and the magnet will be pulled off the switch should you and your trials bike decide to go in separate directions. It decreases the chances of your bike taking out spectators or other riders, and also may save your engine if the handlebar end embeds itself in the dirt with the throttle wide open! Cost is usually around the $40 mark in Australia.

During the machinery inspection, the scrutineers will get you to start your bike and show that your lanyard kill switch is working. They will also check to ensure your trials bike is in proper working order with no broken parts. The inspection also checks the following:

– both brakes are working
– wheel spokes are unbroken and tensioned
– foot pegs swivel properly and return to their position
– wheel bearings and suspension linkages are not worn
– steering head bearings are not worn
– chain guard fitted
– a number plate with your name in letters at least an inch high is attached to the forks
– hand levers have ball ends
– throttle returns correctly
– proper trials tyres with sufficient tread depth
– handlebars have solid ends (5 cent coins under the grips are a cheap solution!).

Your helmet will be checked during the machinery inspection. It will need to be in good working order, and either a proper trials-specific helmet or a helmet that is street-legal (for Australian competitions, this may differ overseas).

While we are looking at riding gear, this is quite basic – the only other requirements are trousers, shirt, and calf-length boots made of leather or a similar durable material. Elbow guards, knee guards/braces and even body armour are all options but technically required.

These are the basics but of course there are more that should be commonsense, such as the exhaust not being overly loud, mud guards must be fitted etc. See Section 19 of MOMS 2018 if you want even more details.


There are possible issues for older bikes in scrutineeringOlder trials bikes will need the fitting of a ‘shark fin’ to ensure feet or hands can’t get caught between the chain and rear sprocket if they don’t already have a chain guard (see pic).

If a very old trials bike has brake cam arms or levers of the open or hooked type, the brake actuating rod or cable must be secured so as to prevent accidental dislodgement.


In addition to the above, this is a suggested pre-ride checklist to run through.

Check all nuts and bolts regularly, especially on two strokes which tend to vibrate them loose. Apply Loctite as a preventative measure. In particular, keep an eye on any bolt that earths your electrical system!

Check your radiator coolant before every ride. There is very little fluid and no overflow bottle so the level can drop quickly. If you can’t see the level, pinch your radiator hose – if this brings the level up to where you can see it then it is close enough to the top for riding.

Trials bikes only have a very small air cleaner so ensure you check this regularly and clean as required.

There’s a similar issue with engine oil – trials bikes don’t carry a lot so make sure you change this regularly. Check the manual for your bike to see how often you should replace it.

Make sure you have topped up the tank – it’s easy to forget and embarrassing to splutter to a halt mid-section. If you have a two stroke, synthetic oil is less likely to gum up your engine.

Check your tyre pressures – the baseline is typically 6psi for the front and 4psi for the rear then these are varied depending on how muddy or rocky the conditions are.

Ensure your forks and rear shock aren’t leaking fluid.

Check your chain tension before riding. Trials bike chains don’t have o-rings so keep them well lubed before riding. After wet or muddy conditions try to clean and dry the chain well prior to lubing.

Check that your tube caps are on front and rear to prevent your tube valves getting dust or mud in them and leaking mid-ride. It’s handy to have at least one cap that includes a valve removal tool on the end.


Apart from your usual tool kit, these are handy items to have on hand for any ride:
– a tubeless tube repair kit for the rear wheel on modern bikes (under $10 on Ebay)
– a front tube and/or a puncture repair kit and pump
– spare nuts and bolts to suit your bike
– a brand new spark plug, especially for two strokes
– a low pressure tyre gauge (available at most automotive stores)
– spare clutch and front brake levers
– Zip ties and gaffer tape – the wonder tools!

This is based on our Youtube video Pre-competition mechanical inspection.

Copyright B. Morris 2014