Dirt Bike Oversized Big Bore Gaskets – Perfect Seal for Big Bore Builds
Complete your big bore rebuild with a gasket set engineered specifically for oversized bore dimensions — because a standard gasket simply won't seal correctly once your cylinder has been bored out. Our oversized big bore gaskets are cut to match your exact overbore size, giving you a reliable, leak-free seal that stands up to increased compression and cylinder pressure.
Why Riders Choose Our Oversized Big Bore Gaskets
Matched to Overbore Size – Precision-cut to common big bore diameters (e.g. +2mm, +3mm, +4mm) so the gasket seals flush with your oversized cylinder, not your stock bore
High-Temperature Materials – Multi-layer steel (MLS) or reinforced composite construction handles the extra heat and cylinder pressure that comes with big bore performance
Complete Top-End Sets Available – Base, head, and exhaust gaskets sold together or individually to suit your rebuild
Reliable Compression Seal – Prevents blown gaskets, oil leaks, and compression loss under sustained high-RPM racing conditions
Wide Model Range – Available for Honda CRF, Yamaha YZ/YZF, KTM SX/SX-F, Kawasaki KX/KX-F, and Suzuki RM/RM-Z big bore kits
Why Fitment Matters
Fitting a big bore kit changes your cylinder's outer dimensions at the gasket surface, meaning a stock-size gasket will either fail to seal properly or restrict ports and passages. Using the correct oversized gasket, matched to your specific bore increase, is essential for maintaining compression, preventing leaks, and protecting your new cylinder and piston investment.
Perfect For
Riders completing a big bore cylinder kit installation
Engine rebuilds requiring an exact oversize gasket match
Workshops fitting big bore kits as part of a performance build
Replacing a blown gasket on an existing big bore setup
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