Topic: 1975 CB400F rebuild and reassembly

[Flyin900]

I purchased this bike last fall from a fellow who had started to restore the bike initially and decided that he didn't have the time to continue with the rebuild. He also realized it was starting to get very expensive for the level of restoration he had started to do and wanted to ultimately achieve.
I received the bike in pieces with the frame, wheels all apart and the motor out of the bike and every other small item in boxes. This was a first for me as I usually buy a bike in a complete yet unrestored form and a lesson learned here and wouldn't do it again.
The good was the frame had been powder coated and the wheels, spokes and tires were all brand new and there was a good assortment of OEM Honda parts that came along with the deal including a new repo muffler. I continued with the building and restoring using OEM Honda or David Silver Spares parts and the wallet is a lot lighter these days.
My goal is to build the bike as close to factory as it was new and have replaced all the fasteners with new OEM Honda or stainless steel cap bolts on the motor. I don't have a lot of pictures of the bike in pieces as it was purchased, yet I have documented the motor rebuild and the addition of lots of new parts or refurbished and repainted pieces as the project has moved along.
The motor was torn down and I have a favorite machine shop that I use for machining and general motor work as needed. The crank and rod bearings were in good shape so no replacement needed. I replaced the rings with OEM and had the cylinders honed and the cam chain and both the tensioner and slipper replaced. I had a complete valve job done and new valve stem seals added and all new gaskets and O rings and seals throughout the entire motor. I put the motor back together a few weeks ago and got it back into the frame just recently.

[Flyin900]

The carbs were a real mess from sitting with old gas in the bowls for a very long time it appears. I was able to get them clean enough to use as a parts source, as I had a mostly complete bank from a previous CB400F build left over. I needed to replace one carb on the better set that had a broken float pin post and did a complete tear down and rebuild to make one good set.

[Flyin900]

I repaired a few areas in the wiring harness and cleaned and repainted all the electrical switches on both side of the bars. The switches are very well built overall and mostly just need to be cleaned and refreshed with new grease and contact cleaner. I am able to respray the covers and paint the red instruction inserts with model paint to look like new. The trick is to paint the covers in a low gloss Duplicolor engine enamel and bake it to harden and chemically resist any material. Paint over the red indented directional areas and wipe with brake clean and their just like new.

[Flyin900]

Frame and wheels and front end reassembly. The frame was mostly powder coated on the key areas and the PO upgraded the swing arm bushings to brass inserts. I repainted the battery box area and have a special liquid black automotive material that rejuvenates rubber and plastic that is discoloured from age. The regulator electrical cover was repainted and any small items within the battery box and PCV system were rebuilt.

[Flyin900]

The frame and motor are reunited here and I have started to assemble the remaining key items such as the wheels and brake assemblies to the build. All the brakes are fully rebuilt with all new components and new rubber/metal lines to ensure no old parts remain within the braking system.

[SOHC4 Cafe Racer Fan]

I repainted the battery box area and have a special liquid black automotive material that rejuvenates rubber and plastic that is discoloured from age.

What is your "special" sauce?

When I operated a printing press, we had a product we used called Rubber Rejuvenator on the rubber rollers of the printing press.  It was nasty stuff, but it seems to condition the rubber rollers after using some other nasty caustic stuff to clean off the ink.  I wonder if that stuff would be good on the rubber bike parts. . .

[FuZZie]

looking good, those carbs had some serious varnish buildup. 

[Flyin900]

I am working on finishing up the clocks after a face refresh and relubing the internals and trying to paint the outer cans in a 15 degree F garage with snow falling outside. I came up with a small box with space heater blowing into the cavity and spraying around into the inside warmth to get the paint to stay. It has been trial and error with a few too many coats initially, so strip and start again. 
Yes those carbs were mostly unusable as the jet towers had serious metal loss once they were cleaned. i have rebuilt lots of carbs and never have I seen a set that bad, although I do have some extra parts now.
Here is the black rubber rejuvenator that I use and it is mainly a refresher for rubber that has started to turn grey from age. I can't say it will help old brittle rubber. I use it mainly to refresh the colour back to black and with a few coats the rubber parts look new again.

[jakec]

I'm not able to see any of these photos, for some reason.

Anyways I have had luck using a product called seal saver, it's a 100% silicon (or latex, can't remember) liquid that moisturizes rubber pretty well.

There is a 400f in pieces near me asking $1800. It's tempting but it's the same thing, they started off by rebuilding the engine and painting the whole thing black. Which leaves the buyer with the question, do you now have to paint everything else black? And with the nice shiny engine and frame, and tank, now I'd have to clean up and paint and rechrome everything.

[spuds]

Holy cow....what a transformation.   Love how you tackled the handlebar switchgear rejuvenation.

[Flyin900]

I was able to finish putting the clocks back together today and I am happy how the paint turned out on the outer cans given the cold environment. I replaced the gauge cushions which are still available from Honda. I have in the past split the crimp ring and this time I pried all around the ring to release the two halves. I prefer the second option although it is a little more time consuming, yet trying to hold and cement the split ring back together is a challenge.
I was able to reuse the crimp ring and used lineman's pliers to go around the old ring and recrimp the original ring without any issues.

Couple of pictures of the finished gauges.

[MoMo]

    nice work...Larry

[spuds]

Really nice work.   It's the combination of a million small details eh?   

Craftsmanship shows.

[Flyin900]

Thank you Spuds... every bike that I restore always gets a high level of attention. This one though has gotten a little off course, as I originally noted at the start of this post the PO started with spending $$$ on quality parts and workmanship. I decided to follow suite and do a full on 100% restoration, so it has become quite over the top financially.

I don't do this to make money, it is a hobby that I enjoy in retirement and I like the challenge of doing different bikes, yet always Honda. For me personally it just gets too repetitive doing the same model over and over again. You become very good at it, yet a one trick pony... and I like more than one trick up my sleeve these days.

I come and go from this and other forums depending on the model I am currently working on presently. The early Goldwings are a passion, since they are such a unique bike and were quite a departure in design, engineering and performance when originally introduced in 1975.

Here's a 1976 that I restored a few years ago that has some unique wheels and accents on the bike.

[kap384@telus.net]

Subscribed.  Great job!  Inspiration for my own build!