S3 - TRS Cylinder Head Inserts (Fits Original Head) 250 / 280 / 300cc

S3 replacement inserts to fit the standard head on the TRS trials bikes.

Please Note: Some inserts are designed to fit the BPMR6A spark plug and some the longer BPR5ES plug. Please contact us if you would like us to check what style is in stock before ordering.  Both styles will fit all bikes, but the correct spark plug is needed.

Available in Low & High Compression

The primary use of the Red higher compression heads are when riding at high altitude due to the air being less dense, they can also be used to increase the torque of the engine but be careful as raising the compression to much may lead to pre-ignition (pinking) and detonation which can damage your engine, a higher octane fuel may be required to prevent this from happening.

The Gold Low compression head is great for riders who want a soft power delivery, it makes the bike easier to ride especially in slippy muddy conditions. Great for beginner riders but even some expert riders use these to tame the bike down and make it easier and more forgiving to ride.

250 & 300 cc

ST-1071-300 (300 LOW)
ST-1072-300-A (300 HIGH)
ST-1246-280-B (280 LOW)
ST-1073-250 (250 LOW)
ST-1074-250-A (250 HIGH)