1971 Honda CB450 K4 - Return to Stock

[Mike450]

I've decided it's time to return my 1971 Honda CB450 K4 back its original stock form. Above is a picture from this morning. Not heavily customized by any stretch but certainly not stock.

Below is a detailed list of the modifications. None of them permanent, and all of them easily reversible.

• 1968 CB350 K0 Headlight Shell (61301-286-670A)
• 1968 CB350 K0 Headlight Assembly (33100-286-672)
• 1972 CB450 K5 Fuel Tank
• 1972 CB450 K5 Side Covers
• Mikuni VM32 Round Slide Carburetors (pre-jetted, replacement carburetor boots)
  • Light Throttle Return Springs (VM34/06)
  • Choke Cable Adapters (002-351)
• Custom CNC machined aluminum boot adapters (Bruce)
• 2-1 throttle cable (SpeedMotoCo via Amazon.com)
• Choke cable (PU Universal Choke Cable for Mikuni Dual 28")
• K&N RC-1252 High Performance Air Filters
• Custom air filter adapters
  • 6063 Aluminum Pipe: 57mm(OD) × 53mm(ID) × 300mm(L)
  • 4-PLY 2.25" x 12" LONG TURBO/AIR INTAKE BLACK SILICONE HOSE
• Renthal Street Handlebars - Ultra Low - Silver
• Redwing KM-C 330 rear shocks
• Digital voltmeter

This was mostly of an exercise in curiosity a handful of years ago.

Mechanically this bike is in excellent condition. Relatively low miles and as far as I can tell the engine has never been apart. It runs fantastic and revs to the red line with no complaints, though I have rarely pushed it that far.

I also plan to install a modern regulator/rectifier and swap over to LEDs for the gauges, indicators, and tail light as I typically do on nearly all of my bikes.

This will be my "hot weather" project for the next month or so. Something to work on when it's too hot to gear up and ride.

 

[Mike450]

Here's a look at the carburetor and air filter setup I was using. It allowed me to maintain a relatively factory appearance and position the air filters neatly behind the side covers.

 

[goldy]

Bravo Zulu! Way too many of these are being hacked to pieces. Will be nice to see this one returning to it's roots. I'm hooked!

 

[Mike450]

Bravo Zulu! Way too many of these are being hacked to pieces. Will be nice to see this one returning to it's roots. I'm hooked!

My #1 rule with my bikes is that nothing permanent be done to the them. With the exception of my CB77 Super Hawk restoration but that one had already been painted and abused beyond preservation.

 

[goldy]

Same here...I always advise people not to do something they can't easily undo...unless they are starting with the very basics, like just an engine, or just a frame and wheels....and never, ever sell off, or toss out your stock parts. I seldom get listened to though...cast ye not perals before swine.

 

[Mike450]

Getting things together for the switch over to LED bulbs for the gauges, indicators, and tail light.

 

[Mike450]

Instant transformation:

Here's what I'm working with. Aside from the NOS right fork ear everything is original. Unfortunately the right side of the tank has a huge dent. Not sure what I'm going to do about it at the moment.

I love unwrapping NOS parts.

A few close-ups for reference.

 

[Mike450]

I was fortunate that the plastic air box covers where in better shape than the original filters themselves.

I had to walk away from the wiring task at one point. Sometimes they go smoothly, some times they don't.

I've gotten in the habit of running additional grounds to give some flexibility in the headlight bucket. This make a huge difference when combining all the various ground connections of different lengths and eliminates some of the "pulling" you inevitably get when trying to cram everything in. I ran this one to one of the screws that secures the condenser to its bracket. I made sure to clean up all of the contacting surfaces and apply some dielectric grease.

Getting close!

I got as far as starting it on the auxiliary bottle. These engines run so smooth! Ran out of time for the day and wasn't able to take it around the block. I have a couple of startup videos, both before, and after the return to stock that I'll post when they finish uploading.

 

[goldy]

Came out great...NOS parts must have cost $$$$ !

 

[pidjones]

I guess you've worked out the gas tank dent, but in case not, check the Youtube videos where a guy uses inner tubes to pop them out.

 

[Mike450]

Came out great...NOS parts must have cost $$$$ !

Fortunately only the one fork ear had to be replaced with NOS. I did see that CMS has a NOS fuel tank for €765.50. Yikes!

 

[Mike450]

I guess you've worked out the gas tank dent, but in case not, check the Youtube videos where a guy uses inner tubes to pop them out.

I haven't completely sorted out the dent yet. I've decided to just ride the bike as-is for the season and mess with it over the winter.

 

[Mike450]

Here's the first half of this project. I did a "before" startup and walk-around with the Mikuni VM32 setup and a more in-depth look at the setup I was running including the choke cable adapters and routing.

[VIDEO]

[/VIDEO]

 

[Mike450]

Here is the 2nd half of the project video. I'm working on addressing the dent in the tank. I'll let you guys know how it turns out.