is it a 500/4 k0 or somit else?

[matthewmosse]

These following my 500/4 sidecar outfit  rebuild will already perhaps realise I have stashed a few spares bikes in the old shed loft in bits. Amoungst the issues I face on my rebuild was a rotten seat pan, and the spares I dug out included what is apparently a 500/4 k0 seat, apparently rare. Came off a k reg bike. Question is have I got an old bitsa, or a k0? Frame number not yet available, it's stuck behind a v twin aircooled honda generator and assorted spare wheels. Same story for the engine and wheels. I did find the headlight braketts, I have 3 sets think the odd ones out have larger refectors at about 2 inches diameter over the others at about 1.5. Sidepannels, missing their badges, definitely very old and far more thin and fragile than any other 500 or 550 side pannels. Front muddy was drilled for a front blade number plate I seem to recall. Switchgear had a thumb screw to lock the throttle at whatever setting you choose, like a criuse controll I geuss, not by the looks of it as a modification but factory fit. Wiring routed through the bars, I seem to recall the rear wheel spindle was different to my others too. Is it sounding like it is a k0. I know 500 k0 are nowhere near the leauge that 750 ones are, but am beginning to think if the bike is not common then it may merit different treatment, especially as things like the warning sticker on the chrome rear muddy were still present and intact when I got this. I was probably going to just rebuild it on minimal budgett trying to keep rust at bay with an oily rag, and re pack bearings with fresh grease. I noticed the seat still has a sticker on there, but seemed to be in japaneese. Trouble with doing anything with it, is it has surface rust, if I repaint I destoy these details, if I leave as is it cannot be used without risking it rotting. If it is not too special then acf50 might be ok to preserve it.

[Trigger]

Matthew, I have a UK CB500K0 and can not find another one in this country. Mine was made in Japan in June 1971, came to the UK in November 1971. A 500KO has a different seat, seat lock, wiring loom, sub harness and the frame and engine number will start with 10......
All the other CB500 four's numbers start with 20..... or 21...... That are the main differences.
The KO seat is not that rare as you can find them in the USA.

[matthewmosse]

I think it might just be one then, engine and frame number begin 1015xxx. Just spent the last 2 hours digging the things out.

[Trigger]

Do you have a V5/ logbook for it?

[matthewmosse]

Nope, number plate, frame and engine numbers, no paperwork. It was a minimal description job on ebay, 2 poorly focused photos, 2 lines of description and about 2 inches of dust. I only just found that the rear exhaust was chromed this afternoon, the dust was that thick on it. Proper barn find. It will need an engine rebuild as it has not had the rocker cover fitted for about a decade probably 2, so need to clean it out. Other than that under the dust it still has the helmet hook sticker by the seat and stuff. Not often one finds a classic that un molested. Bad bit was the price, £100 maiden bid. Happy to pay that for a solid Dunstall exhaust and sound brake caliper.

[SteveD CB500K0]

I have a K0 seat that I bought on eBay USA many years ago.  Bob Wessner on .net shipped it for me as the seller wouldn't ship to the UK.

As my current bike ("Goldie") is a K1, I may be tempted to sell the K0 seat.

Steve

[matthewmosse]

I may well be picking your brains when I rebuild this one. I think I can identify 90% of what came off easily enough, but I also know folk will spot every wrong detail and it would be a shame to fit the wrong bit when the right one is sat right next to it on the shelf and I must confess to being a complete philistine when it comes to getting details correct. I take it k0 500/4 are not that thick on the ground in uk? But more common elsewhere? Again I know very little about the historic side. At time of purchase I merely had half an eye on the bits, and half on the potential free tax, but time was against me on that and kids and home rennovation relegated the bikes to the back burner, bar the rebel 125 that kept soldiering on as daily transportation. Poor thing looks like about 4 winters hit it 

[matthewmosse]

Steve, think my seat is solid enough to be honest, given my cashflow this will be a ratty bike when rebuilt, think I have a slightly torn cover, but have gaffa tape for that. It may even be a bike that is shy of rain, given there is a cb550 k3 I can also put back together and my ntv will probably stick around a while. One thing I think I can be sure of the tank wasn't matt black from the factory, but since it came to me half ratted...... k0 rat bike.

[matthewmosse]

Headlight ears/fork shrouds. Small reflectors or large? My first instince was k0 = small, looking at what I have, I thought then they must be large as I have 3 500/4 bikes, only 1 early but 2 small reflector sets and only 1 large. Patina points to the small ones being right. Help, I am getting k0 disease. Last week I would just have fitted a set and probably not noticed the difference.

[Bryanj]

Main differences

(1) small reflectors with 5mm thread (later big ones were 6mm)

(2) round pins on the electrical panel block connectors

(3) forks have the internal threaded bar from the top nut to damper rod

(4) different pattern on seat cover (large squares I think but Steve knows)

(5) Hook on seat lock with different lock on frame

(6) side panels should have a transfer underneath the 500 four badge saying "Honda Motor Co; Tokyo Japan"


Probably more but thats all at the moment

[matthewmosse]

Thanks for that list. Gives me somethings to check. I think perhaps this is a bit good for me. I geuss it is worth nowt til it is put back together and it is going to need me to be careful about which bits go back too. Fraid re chrome is way past my budgett. I have a horrid feeling the forks may be the only pitted set in my spares pile, it is a toss up between two sets in my spares pile.

[Trigger]

The KO forks have different internal parts. As bryan said, when you remove the top nut it is connected to a bar.

[matthewmosse]

Wiped the dust off the sticker on the seat, seems to be rather a lot of numbers , probably a system of making build date as two rows of numbers 1 through to 12. I hope the forks for this bike are the ones with the gaitors and not the pitted set then, otherwise I will need to re chrome. I think I am decided on what next for this, basic re assembly with fresh grease. Lots of acf50. If needed then fit wrong bits as I am pretty sure the wheels will need rebuild. It will have to wait for my 500/4 sidecar to get done but I will be digging out bits as I go. I geuss photos will be in order. I think I will aim  to take it to Stafford as a ridden exhibit. Un restored. Be interesting to see what reaction it gets. There is no way I have the means to restore properly so rebuild as original as possible. I noticed the seat has red foam topping but the cover has a few small splits.

[matthewmosse]

Found the loom, handlebars and switcgear, but a question arises. To me the switchgear is distinctly different to my other 500/4 which in turn is different to those on my 550/4 (k3), all as expected, including the round multi pin connectors ( are spares available for these? ) so, the puzzle bit..... Why do I have 2 sets of these bars and switchgear, were they the same on a k1? Do I have more k0 stuff than I thought. I geuss from what I have read that 500/4 k0 bikes are far more common over the pond so probably I at some point picked up some us inport bars at an auto jumble or something. Probably Stafford about 10 years ago.

[matthewmosse]

I think I now need to think about getting a log book. It seems the bike is probably not scrap but a worthy project. I have the bike though in bits and a number plate. What else would i need. Ie is it going to need an inspection etc. It has been gathering dust for years.