Topic: '75 CB400F Jumping in at the Deep End

[Brian G]

Good Day Everyone -

After doing a few 'cosmetic' restorations, I'm now into my first 'frame up' rebuild. My wife developed an affection for the CB400F after getting the opportunity to ride one while participating in one of Joel Samick's classic motorcycle Retro-Tours a couple of years ago. Joel's wife Lynn was good enough to share hers with Glenna and she developed an instant liking for the little four.
They're scarce as hens' teeth up in this part of the continent, however - at least at a price we were able to justify to ourselves - so when a barn-find came available for a mere $450 Can. (about 50 bucks US at this point in time  ) I snatched it up and committed to the restoration.



The easy part is over - my garage is cluttered with plastic parts bins and labelled sandwich bags and, gazing into the cardboard box containing the transmission gearsets (cases needed to be split as the camchain tensioner horseshoe was seized solid), I'm faced with the reality of what I have wrought 

This forum has always been of great help with questions regarding my 550 and I've already learned much about the restoration process via the 'Search' function and just browsing others' projects, but I have a few questions (lots, actually, but I'll ask them a few at a time so as not to take advantage of the forum's collective good nature) for which I haven't seen an answer.

The engine cases, barrels and head are away being soda blasted. When they come back, I'll need to prime them. In my younger days, when assigned to paint bare aluminum, we used Zinc Chromate - a sickly yellow-colored primer. I bought a spray can of the stuff from Canadian Tire but then got to wondering if there might not be something better. Anyone care to comment?

After getting her home, closer inspection made it apparent that some major metal butchery had been done on the poor thing at some time in the past.



I cannot imagine what happened here - a section of the frame about 6 inches long was cut out of the frame and welded back (badly) such that the sidestand angle now prevents it from being used. The bike is held 'over-center' if the stand is down. For the first photo above, I had to dig a hole in the driveway gravel 2 or 3 inches deep to avoid having the bike topple over to the right! Explains why it was leaning against a wall when I went to pick it up! A friend who is an excellent welder says he can salvage it but as the wheels and swingarm are off, I'm not sure how to calculate the correct angle to which the section should be rewelded. I suppose it's not vital as long as she leans in the right direction.

Even in this state, it's a nice-looking engine...



Advice, comments and suggestions are always welcome. As they say on E-Bay, 'Thanks for Looking'!

Regards,

[strynboen]

its normal that the side stand takes aut a bit of the frame..
.vater inside can freze and blow the lower tubes too.
..but just weld new tubes inn vith care..and use some inner tubes in the veld areias to get dobbel thikness... and easyer welding..
like the MAD MAX sidecovers...and paint tema...

[przjohn]

Mine had a rewelded side stand too. I think it is a common problem. You may want to just cut down the kstand instead of going back at the frame to get the stand operational. For engine paint I used VHT Hi Temperature Paint in Universal Aluminum on a 400F and a CL90, both worked out well. Best of luck with your project, my Wife loves hers too.

[carnivorous chicken]

Side stands were indeed a weak spot on the CB400Fs. They would fold over and bend really easily -- and it never helped that people would sit on them with their full weight with the stand down. But yeah, easy fix for a welder, and should be able to get it up to snuff cosmetically for a restore.

[jonda500]

Yep common- my first 400-4 had no sidestand, just a big gaping hole in the frame rail where the mounting bracket used to be. To tidy it up I cut out the lowere frame rails (only between the engine mounts!) and used 4 rubber plugs to plug up the frame ends,
John

[Flyin900]

The zinc chromate from CT will work, although I have found it sprays on poorly with a weird coverage that seems kind of washed out. They also sell a DupliColour primer that is an army green colour that is about $15 a can and I like it much better.
The VHT engine paints work well on these Honda motors and stand up to the heat. There is a DupliColour engine enamel that is a perfect match to the original Honda silver. I don't have the code presently yet CT sells it too and there is really only the one silver engine enamel from DupliColour. Solid performance with no heat failure on the DupliColour products too and good chemical resistance once cured.