After the engine was bolted back in the frame it was time for the final reassembly, one of my favourite parts of a resto.
There's an excellent, very detailed guide for a Honda CB550 (very similar to my CB500K1) reassembly on the SOHC forum which I used a lot. Check it out: http://forums.sohc4.net/index.php?topic=151576.0
I started with the steering bearings, front forks, front fender, front brake and front wheel as I wanted the bike to be back on it's middle stand as soon as possible. The steering bearings on this bike were still the original ball bearings but totally shot as over the last 5 decades it had developed a memory and always wanted to go in the same direction.. straight ahead. When turning you could feel some sort of wobble in it like it had to go over a bigger ball bearing.
I bought new tapered bearings at 4into1.com and they were fairly easy to install, just make sure you put the new bearings in the freezer for a day, so they'll shrink a bit which makes installation way easier.
Honda CB500K1 steering bearings
Honda CB500K1 new tapered steering bearings
Honda CB500K1 new tapered steering bearings
Honda CB500K1 steering bearings
Honda CB500K1 old ball steering bearings
Honda CB500K1 old ball steering bearings
When the front forks, fender and front wheel were installed I noticed the front suspension was really stiff and would only go down a couple of cm and I could also hear some weird sounds when putting pressure on the suspension. After a web search I found a possible cause for this... binding forks. This can happen when you install and tighten the front fender before installing the wheel. It can make the front forks twist a bit so they don't work well together. There's a procedure to align front forks which can be read in the screenshot below (Thanks to the SOHC forum):
Honda CB500K1 front fork alignment
I replaced most parts inside the front brake calliper, including a stainless steel piston. Also new brake hoses and copper washers. But when everything was installed I couldn't build pressure in the system and had to take the master brake cylinder off again. Roger checked the master and discovered one of the tiny holes inside was blocked by some hardened grease. After temporarily removing all the internal new parts he put on a welder glove and burned the hell out of it till it popped out. All good now.
When you install the master brake cylinder make sure the punch mark on the clamp is orientated to the bottom and tighten the top bolt first.
Honda CB500K1 front brake master cylinder
Honda CB500K1 old front brake hoses
Honda CB500K1 front brake connector block and switch
Honda CB500K1 new front brake calliper parts
Honda CB500K1 new front brake caliper parts
Honda CB500K1 new front brake hose
Honda CB500K1 front brake master cylinder hose
Honda CB500K1 front brake lines
Honda CB500K1 installing new front brake lines
Honda CB500K1 front brake info
Honda CB500K1 front brake calliper installed
Next thing to do was the rear shockers, rear wheel, a new O-ring chain, chain guard and new rear fender. The new rear fender from Vietnam was pretty difficult to install because the bolt holes didn't exactly match the frame holes but after some wiggling I managed to fit it. Btw before I installed the rear fender I mounted the rear light unit and fed its wires through the cable gutter at the underside of the fender. Roger came over with a special tool to install the new O-ring chain.
Honda CB500K1 wheels installed
Honda CB500K1 fitting new O-ring chain
Honda CB500K1 new O-ring chain
Honda CB500K1 new O-ring chain
When I took the old original rear shocks off the bike they seemed to be ok but after laying horizontal in a box for a couple of months one of them started leaking. Unfortunately you can't repair this so I decided to buy a pair of shiny new ones at CMS. They look similar but I reckon they're of higher quality than the original ones, which is a nice bonus.
Honda CB500K1 old and new shocker
Honda CB500K1 new shockers
The next thing to install were the carbies together with all 8 boots and air filter assembly. When installing the outer intake boots make sure the dots on the boots line up with the dots on the plastic air filter plenum.
Honda CB500K1 carburetors with new boots
Honda CB500K1 carburettors with new boots
Honda CB500K1 installing carburettors
Honda CB500K1 carburettors with new boots
Installing new boots in plenum, note the lined up dots on both
Honda CB500K1 installing the carbies and air filter box
Honda CB500K1 installing air filter box
Honda CB500K1 new air filter
Honda CB500K1 new air filter installed
Honda CB500K1 air filter box drain hose
Honda CB500K1 air filter box drain hose
After I installed the push and pull throttle cables I discovered that one of them was damaged so I ordered 2 new ones and had to put the whole project on hold for a week.
Honda CB500K1 push and pull throttle cables
Honda CB500K1 routing the push and pull throttle cables
Honda CB500K1 routing the throttle cables
Honda CB500K1 routing the push and pull throttle cables
The next step was installing the 4 original "HM CB500 SL HM323" exhausts. The bike came with a 4in1 exhaust but I found a nice set of 2nd hand original pipes and bought 4 new pipe brackets. Before I started the installation I inserted the copper gaskets into the exhaust ports, slipped on the joints and then "hung" the pipe headers in the cylinder head exhaust ports. Don't mount the joints over the exhaust studs yet because it will make the whole installation only harder. Next step is lining up the mounting bolt holes of the 2 pipes and mounting bracket and at the right moment push the bolt with rear foot peg through the aligned holes. This can be a bit of a fiddly job as the header(s) can fall out of the cylinder head while moving them trying to align everything. Also make sure everything is in the right sequence (see also the parts manual) And while trying to align everything you also need to put the balancing tube at the end of the two pipes in place. .
Exploded view parts exhaust system Honda CB500K1
Honda CB500 four new exhaust mounting brackets
Honda CB500K1 exhaust pipes
Honda CB500K1 exhaust pipe balancing tube
Honda CB500K1 exhaust system parts
Honda CB500K1 muffler parts
Honda CB500K1 exhaust gaskets inserted in ports
Honda CB500K1 installing the left pipes
Honda CB500K1 left pipes loosely installed
Honda CB500K1 all pipes installed
Honda CB500K1 exhaust pipes right side
Honda CB500K1 exhausts installed
Nice :)
After the 4 pipes were installed everything went fast, fuel tank, side covers with new grommets and seat were all installed within 30 minutes and all of a sudden I was standing in front of a very nice and shiny bike.
1972 Honda CB500K1 next to Volvo 122S 1969
1972 Honda CB500K1 exhausts close up
1972 Honda CB500K1 engine close up
Now it was time for the big moment.... starting up the rebuild engine. After a few goes the carbies were all filled with petrol and the bike gave some pops and coughs. We let it sit for a minute or so and then hit the starter button again and with the choke on it started running... and it sounded very smooth and awesome :)..
Honda CB500K1 1972 first start-up after engine rebuild and resto
Within a couple of minutes it was warmed up and the engine started smoking like crazy... just the new engine paint curing.. I switched it of and let it cool down so the engine paint could further cure.
While it was cooling down we put Shaine's CB750 next to it and made some nice pics.
1972 Honda CB500K1
Honda CB500K1 and his big brother the Honda CB750
Honda CB500K1 and his big brother the Honda CB750
Honda CB500K1 and his big brother the Honda CB750
A week later I started the CB500 again so the engine paint could cure a bit more. It started smoking again after warming up, but not as heavily as the first time. As the bike didn't have a rego plate yet I couldn't take it for a real testdrive. Instead I drove it up and down the driveway. After 2.5 miles it was still running, no weird sounds or other unwelcome surprises.
Now everything seemed to be working I decided to take the bike to an ID-inspection station 10km from my home. After paying 48 AUD I got a one day permit. We normally don't get a lot of rain over here but of course that day it was raining.. anyway a good test run for the CB500K1. All went well, it's a very smooth running engine, no hiccups.
Honda CB500K1 waiting for ID-inspection in the rain
After filling out some paperwork and waiting for an hour the bike got checked. All good yess! I drove it back home, gave it a quick wipe and went straight away to a service customer centre to get it registered. Because I put the bike on historic rego with the club earlier, I didn't have to pay any stampduty. At the end I paid 198.02 AUD which included 1 year historic rego, the ID-inspection and a new numberplate.
When the weather is a bit better I'll do some more testriding and maybe a photo shoot, but for now I cleaned the whole bike again and put the Honda CB500 in the lounge room so everything can dry a bit more. It had some condensation in the speedo, but after removing the lightbulb and hitting it with a hair dryer for 5 minutes it seems to be ok now. I think this is more common with the older CB500's where the gauges are positioned a bit more horizontal than on the later CB500 versions.
