Sprint Filter P08 Air Filter for Road & Track – KTM 690 SMC R / Enduro R (2008–2018) PM74S

The LC4 in a 690 is one of the last motorcycle engines genuinely expected to be opened. Piston, valves and clutch are published service items with intervals attached, and the people who own these bikes tend to do that work themselves rather than hand it over. An air filter designed for the life of the motorcycle fits that ownership pattern from the opposite direction: it is the one intake part that stops appearing on the parts list at all. PM74S is dry woven polyester in the standard housing, washed and refitted for as long as the bike is kept.

Key Features

• Dry woven polyester, used without oil and never treated after washing
• Filtration 80 microns; flow 5,050 litres per square metre per second
• Threads from ø 22 microns — a thread diameter, not the mesh width
• Around twice the filtering area of other performance filters
• Drops into the standard airbox: no modification, no remap
• Two years of warranty from purchase

An engine built to be opened, a filter built not to be

A 690 that has been kept properly has had its top end apart at least once. That is normal for this motor and part of why the bikes stay on the road. The air filter is the opposite kind of component in the same intake: meant to come out, be cleaned and go back in without ever being bought again. Sprint Filter designs the element for the life of the motorcycle, which on a machine like this means a great many cleaning cycles. Dry polyester returns close to its published figures each time it is washed, rather than drifting steadily away from them until somebody fits a new panel.

What a big single does not get from it

Power. A single of this size has a loud, dramatic intake and it is tempting to read the element as a tuning part, but it is not one, and it will not make a standard 690 noticeably stronger: the throttle body, the cam and the calibration set the ceiling, and a panel inside an unmodified airbox moves none of them. What it does is stop the restriction climbing between services, and it removes oil from the intake entirely, so nothing can travel downstream. On a bike whose own production ended in 2018 there is a second, quieter argument: the part number is kept current by machines still being built on the same housing.

Care and cleaning

Compressed air first, through the element from the clean side outwards. Warm water and a mild detergent when air stops lifting anything, then a rinse until the water runs away clear. Dry it in air alone, well clear of heat guns and flame, and refit it only when it is dry through — the material must never be dried with heat. There is no oiling step at the end. Sprint Filter's maintenance sheet for PM74S is in the Downloads tab of this page.

Fitment & Compatibility

For the KTM 690 SMC R and 690 Enduro R built between 2008 and 2018. The same element also serves the Husqvarna 701 Enduro and 701 Supermoto, three machines in all, and the Fitment tab lists them in full. Those two Husqvarnas are still in production, which is worth knowing when sourcing consumables for a KTM whose own build run has closed.