Bigbore 100cc Cylinder kit, HQ Racing Crankshaft and C4 bearings Yamaha DT LC/D VOCA Racing

Voca Racing kit consisting of a Cylinder 100cc BigBore, HQ crankshaft and bearings , designed for Yamaha DT LC/D. This set offers the perfect combination of performance, durability, and reliability for 100cc BigBore-type setups.

The Cylinder Voca BigBore 100cc is made of aluminum with a chrome/nickel coating and features 5 transfer ports and a bridged exhaust port. It is supplied with a 53.95 mm single-ring Vertex piston. The cylinder head is not included; it is recommended to fit the VCR-RD11DT.54 with a recommended Squish of 0.8 mm.

The Voca HQ Racing 43mm crankshaft incorporates an 85mm Connecting rod and is manufactured with high-quality materials, balanced with aluminum and bronze inserts to optimize rotation and increase pre-compression without the need to machine the crankcase. It is designed to reach up to 16,000 RPM and support 54 mm pistons.

Crankshaft features

• Stroke: 43 mm
• Connecting rod: 85 mm with 12x17x16 mm bearing
• Crank webs: 77 mm for maximum pre-compression
• Upper aluminum and lower bronze counterweighting
• Closed design to increase pre-compression in the crankcase
• Connecting rod CNC-machined with laser-engraved logo

The kit includes high-speed SKF C4 bearings with TN9 cage, capable of withstanding up to 20,000 RPM, together with Corteco/KOK Viton seals to ensure sealing and durability.

Contents of the bearing and seals kit

• 2 x SKF 6204 TN9 Bearings - 20x47x14
• 1 x Oil seal 20x40x8
• 1 x Oil seal 28x48x8

Requirements and recommendations

• The reed valve VForce 4 Yamaha YZ 85cc must be used.
• Combine with the recommended VCR-RD11DT.54 cylinder head
• Check balancing before assembly to ensure warranty.

Application

Kit valid for Yamaha DT 50 Portugal, Yamaha DT 80 LC, Yamaha RD 80 LC, and Yamaha TZR 80 LC engines. Recommended for high-performance sport setups and displacement increase to 100cc.

Main features

• Cylinder 100cc BigBore with Vertex piston and 5 transfer ports
• HQ Racing 43mm crankshaft with 85mm Connecting rod and optimized pre-compression
• High-speed SKF C4 bearings and Viton seals
• Maximum performance in Yamaha DT LC/D and TZR 80 LC engines
• Complete 100cc BigBore-type setup

Important

It is essential to carry out balancing checks before assembling the set. Any balancing issue detected after assembly may void the manufacturer's warranty.