Topic: CB500K1 reviving a survivor

[volare71]

 
Sei di Maggio, a great day to revive a '72 CB500K1.  I purchased this project last November and have been slowly going through It's issues while starting a top end job on a "72 CB350F and maintaining my stable of old Honda's.  When I brought it home the front brake was seized, the gas tank full of varnish, the side covers in pieces, the seat completely rusted out, and the carb rack welded closed with the same varnish.

Yesterday it fired up and proved it's electrical system, engine and transmission basically intact.  If fact when we hooked up the new battery the neutral and oil lamps lit up.  We had just finished a complete overhaul of the four carbs with new jets from the K&L kits and a new finish thanks to my glass bead blaster.

As this post progresses I will share experiences and the Issues as I faced them:
1. Removing and tackling the varnish in the fuel system.
2. Freeing up the seized front disc brake and rebuilding it from top to bottom.
3. Addressing the rusted seat pan and building a new seat
4. rebuilding the carb rack.
5. rebuilding the front suspension including new taper roller bearings.

My goal is a rideable survivor that has the patina and scratches that come with an age of 41 years.

[brooze72]

Good stuff, an excellent to do list, add tires & that will make it rideable & safe.  Those rims & fenders look in good shape!

[volare71]

 
My first issue was the varnish in the fuel system.  the tank, petcock, fuel lines, and carburetors were awful.  I began by removing the tank and inspecting the petcock.  I used concentrated carb cleaner and a gallon of overnight carb dip from NAPA extensively to get the varnish out.

Tomorrow I'll add the electrolytic tank cleaner jpgs.

[brooze72]

Hopefully it's just the way the picture of the top seal is displayed, it appears to be cracked?
Photo of the varnish is a classic . Check out a large number of posts on techniques to clean tanks in our threads.

[volare71]

The second big task was the carburetor rack that sat and was fed gas until it all gelled.  this called for some deep carb dipping in NAPA 4260 carb cleaner.  The bowl drain screws required a vise grip to carefully undo them with their deteriorated O rings.  Fortunately the slides were good, even the number 4 slide that was stuck when we took the rack off.  the needles were clean but the main and idle jets were worthless and replaced with the K&L kits that we used.

 Several days of cleaning and replacing all of the float bars with 3/32 brass rod and replacing one float allowed a rebuild that we were proud of.

I made a homemade float height gage to set the floats at 22mm.   The carbs were rough synced by peering at the slides in the idle position and adjusting them for even height with the slide adjusters.  this got us close enough to use the vacuum gages after we warmed up the engine.

The vacuum gages were easy to attach using the inlet screw ports and the brass tubes with O rings supplied.  After the engine was warmed up the fine synchronization was performed and tested at idle 2000 rpm and 3000 rpm.

the photos show the before and after views of the carb rack.

[Steve_K]

Those carbs look  pretty good.  Glad that the carbs synced up and she idles well. 
Steve

[volare71]

 

 Last week I took it for it's first ride on a pair of Dunlop K70s.  Used a lawn chair pad for a makeshift seat and rode it up to 100 km/h and several miles.  Very happy with the handling and performance.  Had to drain the carbs and fly to Italy for my niece's wedding! Darn

[volare71]

 
The 1972 CB500K1 is on the road again.  The engine runs strong and pulls through all the gears.  My only remaining electrical glitches are the turn signals.  With new brakes, tires, carbs, and seat she is looking like a true survivor rather than a a bunch of ebay parts.  I plan to ride it a while to see if it needs some interior engine work or just some quality riding time.

This may just be my size of SOHC four.  However I have a 350F project that I will start concentrating on.

[Bankerdanny]

A nice little rider. Enjoy!

[volare71]

 
Finally have the CB500K1 dialed in and running well with some assistance from TJ Jackson at Eastside Performance in Mesa. AZ.

the February weather is perfect for riding here in Central Arizona and the carbs are dialed in and idle as well as it did as a new bike.

i have now gone through virtually every major system and am using all new consumable parts including brakes. chain, sprockets, clutch, cables, new Dyna ignition, carb re-build and jetting, tires seat, all balls steering and suspension.  It is stable and feels good going down the freeway at 70.

My major lesson learned is that you cannot take shortcuts on a 42 year old machine, not if you want to ride in traffic with reasonable safety.

I still am unsure about the re-paint cosmetic issue, but am happy that I have a fully functional bike mechanically.

[brooze72]

Good job.  I envy your weather!  Cosmetics are just that, I would ride it until you decide what to do and have some down time to do it.
Are you just talking tank & side covers?  If so, keep your eyes open for a set you could repair/repaint for a switch out.  Your old ones then have some value to recoup a liitle cash.

[volare71]

  Just drove the CB500K1 on a 200 mile run to the Grand Canyon and back with the West Coast VJMC rally held in Flagstaff this year.  Bike ran fine at 50-70 mph on the run with no issues.

[Stev-o]

I missed this thread first time around, nice job! No pics of the bike at the Canyon?