The Long Haul Part 2: Servicing the Honda CB450 Engine

Posted by W. D. Hesser on 6/5/2018 to CB450 / CL450 / CB500T
The Long Haul Part 2: Servicing the Honda CB450 Engine

The Long Haul Part 2: Servicing the Engine

Texas to Ohio to Minnesota and Back Again on a 1974 Honda CB450

Section 1: The Bottom End

The heart of a motorcycle is its engine, and is naturally the first place to start when making your way through the overhaul process. Different bikes require removing different parts to access the bottom of the motor.

    Our CB450 required the removal of the following:
  • Oil Drain Plug
  • Gas Tank
  • Shift Lever
  • Kick Start Lever
  • Left Foot-Peg
  • Mufflers & Header Pipes
  • Chain Cover & Clutch Cable
  • Rotor Cover
  • Right-Side Engine Cover
  • Carb & Intake Manifolds
  • Valve Covers
  • Points Cover
1974 Honda CB450 After Initial Disassembly
1974 Honda CB450 After Initial Disassembly

Once all the oil was drained and the engine covers were removed we could tend to the lower parts of the engine starting with the right side - specifically the clutch and the oil filter. We fitted the clutch with new friction disks and springs and we gave the oil filter a thorough cleaning. The engine covers were then reassembled with fresh gaskets and a set of stainless steel Allen-head bolts.

Right Side Of Engine With Clutch And Oil Rotor Removed
Right Side Of Engine With Clutch And Oil Rotor Removed

Rebuilding the clutch on a Honda CB450 is a fairly straightforward process, and is similar to most bikes of this era. Although the centrifugal oil filter is found on a number of early Honda CB models, this feature is fairly unique to these bikes. To see how it’s done in detail, watch our video showing how to clean centrifugal oil filter.

Section 2: The Top End

Once the bottom end was buttoned up we moved on to the top side of the engine, specifically the cam-chain adjustment, cam lobe inspection, and valve tappet clearance check and adjustment. No special tools are required for this part of the procedure other than a set of feeler gauges. These maintenance procedures are standard and should be carried out at Honda’s recommended service interval. Instructions can be found in the Honda Factory Service Manual

Honda CB450 Engine Left Side
Left Side of the Engine with Chain Cover, Carbs, Valve Covers, Rotor Cover, and Points Cover Removed

Watch our how to make a Honda CB450 (and CL450 Scrambler and CB500T) Cam Chain and Valve adjustment video:

The last step in the engine tune-up process is setting the ignition timing, but before we do that we will inspect and/or replace all of the major electrical components on the bike. So stay tuned for the third installment of our Long Haul CB450 Project: The Electrical System

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