TB Race Head, 88cc Big Bore Kit, & 20mm Carb Kit – Z50R XR50 CRF50 1988+

TB Race Head, 88cc Big Bore Kit, & 20mm Carb Kit – XR70 & CRF70

TBparts complete 88cc bore kit, Race Head, and 20mm Performance carb kit. This complete 88cc Race Head Kit will really wake up your stock engine and is comparable in power to the much larger Chinese 124cc engines!!! They are extremely reliable as well! Made to our specifications turning your worn-out stock engine into a high-quality, high-performance engine that makes big power!

Starting with the 88cc 52mm Big Bore kit. Our aluminum steel sleeve cylinder is super lightweight compared to stock and it also helps with heat dissipation. The piston is high compression but safe for 91+ octane pump fuel. The bore kit also includes the top end gasket kit that includes all the gaskets for the job.

Next is the race head included in this kit. This is what really sets our kit apart from the competition especially considering the price. When you replace your worn-out, carbon built up stock cylinder head with our new complete bolt on race head you get a ton more performance and power. Better geometry allows for a bigger cam, larger valves, and bigger, better porting. Plus, it is made to our specifications to keep quality in check with OEM standards. This is extremely important when turning big RPMs and making big power.

Top that off with the 3mm larger 20mm performance carb kit to feed the new larger displacement engine. This also includes a port match manifold with all the necessary hardware. We now include our High-Volume oil pump that feeds the new top end 2x the oil for free and a performance CDI.

Key Features –

• Lightweight aluminum cylinder with steel sleeve
• Cast in mounts on cylinder for aftermarket skid plates
• Oversized cooling fins on cylinder for efficient heat dissipation
• 52mm high compression piston with rings, pin, & clips
• Head gasket kit and clutch cover gasket.
• High performance race camshaft (for the Race Head only)
• Race Head with larger 25/22mm stainless steel (21-4N material) valves for better flow and increased performance. Also has bigger cooling fins. Includes all necessary parts and comes assembled!
• 20mm Performance carb assembly. Includes: 20mm carb, port matched intake, heatstop, gaskets, mounting hardware/wrench, long adjustable throttle cable, and an angled dual layer foam air filter.

UPDATE – Until further notice, this kit will also include the following items at no extra charge!!!

• 6 Piece main jet kit for the 20mm carb ($10 savings)
• High Volume oil pump ($25 savings)
• Clutch cover gasket ($3 savings)
• Performance CDI ($25 savings)

$63 total savings

This kit works on the following models:

• all XR70 & CRF70

Installation Notes: It will save a lot of time and effort if the oil pump is installed while installing the bore kit (requires cylinder removal). (For the 88-91 Z50R, the newer style 2 bolt cam sprocket will be needed. We have them available in this section and the part number is TBW0861)