Northern Lights — Retightening Cylinder Head Bolts
Maintenance
From a Northern Lights operator's manual covering: NL378, NL378x, NL484, NL488x, NL498x. Check it applies to your exact model before use.
Applies to: Northern Lights NL378, Northern Lights NL378x, Northern Lights NL484, Northern Lights NL488x, Northern Lights NL498x
Procedure
- Retighten the head bolts after the first 50 hours.
- Tighten bolts when the engine is cold.
- Loosen nuts and remove rocker arm cover.
- Tighten head bolts with a torque wrench in the order shown in figures.
- Tighten bolts evenly in 2 or 3 passes, ending at specified torque in final pass.
- Replace rocker arm cover.
Tools required
- torque wrench Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- See cylinder head bolt torque table
Full service-parts list: Northern Lights NL378 →, Northern Lights NL378x →, Northern Lights NL484 →, Northern Lights NL488x →, Northern Lights NL498x →
Source: Northern Lights operator's 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.