Hercules — Valve Clearance Adjustment
Adjustments · cylinder head
From a Hercules service manual covering: D-1500, D-1700, D-2000, D-2300, D-3400, De3000. Check it applies to your exact model before use.
Applies to: Hercules D Series engine
Procedure
- Rotate crankshaft until both intake and exhaust valves of No. 1 cylinder are fully closed.
- For cold engine, use 0.016- or 0.017-inch feeler gauge between rocker arm and valve stem; adjust screw until it just touches pushrod.
- Adjust remaining valves in firing order.
- Start engine and warm to operating temperature.
- With engine running at slow idle, check for 0.015 inch clearance; adjust as required.
- Reinstall cylinder head cover and gasket.
Tools required
- Feeler gauge Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Hot clearance 0.015 inch; cold clearance 0.016 or 0.017 inch.
Source: Hercules service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.