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Discussion Starter #1 (Edited)
This posting is long. It is what I did to my CB450 K5. Going in all I knew was I wanted a 450 DOHC and after 44 years working in aerospace I had a lot of mechanical experience. I had never restored a motorcycle before. The surprise came when I discovered how mental the process is. I hope this posting can serve as a guide for those who are considering brining an old Honda back to life.

This is what the bike looked like on the day I brought it home back in September '09:

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After sitting in the back of the garage for 5 years and then starting work in March of 2014, it went on the first ride May 2, 2016:

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Brakes (Safety Item):
Front replace the hoses, disassemble and clean master cylinder and the caliper.
Replace the brake shoes or pads unless you know they are new. The lining will disbond from the frame.

Cables (Safety Item):
Ensure Clutch, Throttle and Front Brake cables are free of movement and are properly lubricated.

Tires (Safety item);
Replace if they are 5-7 years past the manufacturing date.

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Wheels (Safety Item):
Remove the wheel bearings, clean inspect and regrease or replace with modern equivalents.

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Suspension:
Remove and disassemble the front shock struts, check the stanchions for pitting and straightness. Install new seals.
Remove the fork bridge, clean and regrease the bearings or install a All Balls tapered bearing kit.
Remove the Swing arm, clean, inspect and regrease the swing arm pivot. Replace the bushings and seals.
Verify the rear shocks have good dampening or update with modern shocks.

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Frame:
Remove the center stand and rear brake lever. Clean, inspect the parts and regrease.
Clean, inspect, remove corrosion and refinish any bare metal.

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Fuel Tank:
Ensure the interior has absolutely no rust is in it. If there is any rust, install a tank liner. There are good products available. The liner will allow the tank to be drained during the winter with out worry of new corrosion. The engine depends on a clean uninterrupted supply of fresh fuel.
Remove the petcock, clean, inspect replace the seals and strainer.

Electrical:
No shorts in electrical system. All fuses in good working order. Inspect every wire in each circuit. Make sure the wire is free from any damage, runs to the correct electrical appliance and all previous repairs are in good shape. Ensure every light bulb is the correct wattage and cross reference to the Honda specified bulb.
Verify function of brake light switches.
Charging system in good condition and charging according to factory specs. Replace to regulator and rectifier with modern equivalents.
Battery new or tested good.

Ignition System:
Replace the coils and wires. Install an electronic ignition or new points and condenser. Oil and service the points and advance mechanism. Set gap and dynamic time the engine, left and right cylinder. Ensure the advance mechanism will reach the full advance. Install new plugs.

Carburetors:
Disassemble, clean, verify all passages are clear and fuel or air will pass. Clean each jet by inserting a wire through the fuel flow path, flush with aerosol carb cleaner. Ensure the needle is not worn and replace the main jet. The needle must float (move) in the slide. Replace the felt seals on the throttle shaft. Ensure the slides move freely and the vacuum pistons or boots are free from leaks, tears and are supple. Install new isolators. Bench sync the throttle valves and set the float height.

Engine:
Remove from the frame and disassemble. In accordance with the Factory Service Manual do the following.
Head: Inspect the cam shaft, followers, valves.
Inspect the cam chain, rollers and tensioner for wear.
Cylinder Block: Check the cylinder for roundness and taper. If within spec use a glaze breaker to roughen up the cylinder walls. If they are out of spec have a machine shop machine hone or rebore. Pistons: verify the ring to grove fit is correct. Worn pistons will allow ring flutter and reduce compression at high RPM.
Install new rings and pistons as required.
Crankshaft: Verify the rod small ends are within spec.
Check the crank bearings.
Verify the oil passageways are clear including passageways through the crank.
Left Side Cover: Remove the rear side cover and disassemble the sprocket, clutch mechanism and remove the neutral switch (if equipped).
Remove forward cover, clean and inspect the stator and wiring.
Right side cover: remove the clutch, oil pump, shifter linkage and shift detent. Make sure the detent roller and the selector are not worn.
Crank Case: split the upper and lower halves. Clean any sludge from the lower section. Inspect the shift forks for straightness and wear on the fork faces.
Inspect all gears, dogs and splines for wear and chips.
Clutch: inspect the plates for wear and flatness. Check the springs for height and straightness.
Inspect the clutch basket inner and outer for smoothness where they contact the disks.
Soak the plates in clean motor oil before reassembly.
Assemble: Reassemble in the reverse order making sure all components are clean and free of debris.
Use generous amounts of quality assembly lube.
Clean all gasket and seal mating surfaces and ensure they are flat and scratch free. Use RTV Silicone seal similar to Honda Bond on the seal edge between the upper and lower crankcase halves. Carefully apply the seal on a thin and even line that will not squeeze out. The squeeze out will break off inside the engine and clog the lubrication system.
Use anti seize compound on all threaded parts.
Install new seals and quality gaskets. Do not use gasket sealer.
Set the piston ring gaps at 120 degree intervals.
Set the cam timing and use a staked master link.
Gently turn the engine over by hand. Stop if any resistance or binding is felt.

Final Assembly:
Install suspension front and rear. Ensure all parts including the upper fork bridge D shaped washers are installed. Service the front shocks to the correct type and quantity of fluid.
Apply adequate grease is applied to all moving surfaces. Check the range of free movement.
Check the tire manufacturing date to ensure the tires are no more than five years old.
Install the tires and wheels.
Install handlebars and battery tray.
Install brake lever and pedal. Run front brake cable or fill and bleed the front brake.
Adjust brakes.
Install the engine into the frame. Ensure the ground between the frame, engine and negative battery cable are clean and free of paint or powder coating. Assemble this joint with wet primer.
Fill the engine with the correct quantity and grade of oil. Be sure to use Chevron Delo 400, Shell Rotella or a oil specifically designed for motorcycles with wet clutches.
Adjust clutch.
Install fenders, speedometer — tachometer.
Install wiring, rectifier, regulator lights (less headlight) and coils.
Hook up wiring and check continuity.
Install the carbs airfliters, exhaust and foot pegs.
Connect spark plugs and static time the engine.
Install battery and check each circuit for function.
Install seat.
Install gas tank, hook up fuel lines and partially fill with fuel.

First Start up:
Turn the fuel tap on, press the start button and if you did everything listed above correctly, it will start.
Hold the engine at a lower RPM.
Listen for any abnormal sounds.
If the engine races shut it down and determine the cause.
Allow the to come up to operating temperature. If the engine was painted with engine paint, the paint will cure.
Check for oil leaks.
Repeat the heating cycle two or three times. Do not allow it to get hot.
Stabilize the idle as much as possible and dynamically set the timing for both pistons.

First ride:
Check tire air pressure.
Check Brake operation front and rear.
Start engine and away you go.
Go for a short ride and bring the engine up to operating temperature.
Return to base and check the bike for function and leaks.
Do not exceed 2/3 throttle for the first 600 miles.

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This is an AMAZING post... THANK YOU for posting this. Super helpful.

And wow, a lot of work you did to the bike!
 

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Great job but aside from brakes cables and tires(safety stuff) l would consider what you did a restoration and way more than what is required to get back on the road. Just my two cents.
 

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Did you switch out the handlebars and if so what is the new bar? Are your happy with the riding position? Any lessons learned with the install?
 

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Haven't heard from jamespal in awhile, hope alls good. I know he used the popular cb400 bars and really liked them.
 

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Thanks Lefty
so am I looking for the Honda CB400f bar or aftermarket if I want to use it on my 71 CB450?
I’m assuming all the cable routing would be external?
 

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1406382351095_slide-500x375.jpg Hi James, Thanks for the info, thats been most helpful. I've found another CB450s in better condition with just 29k kilometres on the clock! Its been stood a while so the obvious things will need to be attended to before I can get it back on the road! photo attached! Once again thanks for the advice. regards Busby ps the 450s is an SOHC engine so maybe I'm in the wrong section?
 
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