1971 CB500K0 Resto 3/71 VIN 1000896

[AshimotoK0]

Ash I have a genuine Honda points base plate complete with wires and points etc lying around. If you want it you can have it, I'll include it with the front disc when I send it, still waiting on that one as I think maybe you'll need some more parts and cheaper to send them all together.

Cheers Ken..will be in touch as soon as I have stripped the bottom end

[UK Pete]

i hope the bottom end is a lot better ash
pete

[AshimotoK0]

You can come out of hiding James, the bottom end looks pretty good  . Not measured anything yet but no horrors in there. No metal in sump.

Only sadness is my man with the magic micrometer hands died suddenly last summer. RIP Alan .. sure you are up there watching me.

Barrels were a bit of a tw*t to get off but my old mate Bryan on here put me straight on that one.

Here are some pics.

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[Trigger]

What is with all the war paint

[UK Pete]

Thats great news ash, honda bottom ens seem to be quite robust
pete

[Bryanj]

Looking at those bits, especially the tensioner that engine has done sod all miles mate, you said one bore had a ridge silly question but was it wear or just a carbon ridge?

[AshimotoK0]

Looking at those bits, especially the tensioner that engine has done sod all miles mate, you said one bore had a ridge silly question but was it wear or just a carbon ridge?

 No its definitely a proper ridge mate but the pistons look OK.  BTW loads of people on here have been bloody marvelous giving me sound advice but I must say you have been an absolute diamond to me Bryan.

A guy in Germany is breaking a couple of 500's and is looking to see if the barrels are OK on any of them.

I just love the design of that 500 engine plus seeing some old friends from my CB250's in there like the shift drum (have a NOS one of them to put in it if needed). Took my trusty home made ,in 1980, peg spanner in to work today ...... as used on CB750,CB175,CB250 etc but not needed on the 500 after all that. Used a CB250  brake lever spindle/bolt to extract the primary chain shaft whatever its called.

[JamesH]

Looking good ash. Happy days.

[Bryanj]

I have several sets of cylinders but condition unknown mate

[AshimotoK0]

Everything looking  OK APART from the cage of the 20mm needle roller which is toast and the needles are slightly scuffed. It's the same part as CB250/K a  ---286---  part No. Luckily I have a spare 250K4 gearbox with decent 20mm bearing in it and the 500 shaft surface finish looks fine.. The bearing is branded Koyo on the 250 and different design of needle cage. It's unbranded on the 500K0 .The bottom end has never been apart before on the 500. Is this a known issue with the 500K0 gearbox?

Unfortunately the mega cheap GENUINE Honda 400/4 20mm needle roller bearing from Yamiya is open construction but possibly the rollers and cage could be swapped. Literally loads of CB250/350/CL350 gearboxes out there though. centre gear selector and selector shaft both the same as the CB twins too.

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[Trigger]

Have come across this problem with the needle roller on a couple of the early 500K0 engines. Check to see if you have these parts fitted : oil guide plate 23106-323-000 and bearing plate 23102-323-000. The ones I had needle roller problems never had these fitted.

[AshimotoK0]

Have come across this problem with the needle roller on a couple of the early 500K0 engines. Check to see if you have these parts fitted : oil guide plate 23106-323-000 and bearing plate 23102-323-000. The ones I had needle roller problems never had these fitted.

Got the 2nd item Graham as I remember taking it off yesterday. Didn't see the first one though, pretty sure the engine doesn't have it fitted.

[AshimotoK0]

This is for anyone who doesn't already know this  CB250 & 400/4 parts on CB500K0. There are also a few small parts that are CB450 and c72 CB72 parts too.

400/4 parts are available from Yamiya but sadly they don't do parts for the 500.

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[Trigger]

Have come across this problem with the needle roller on a couple of the early 500K0 engines. Check to see if you have these parts fitted : oil guide plate 23106-323-000 and bearing plate 23102-323-000. The ones I had needle roller problems never had these fitted.

Got the 2nd item Graham as I remember taking it off yesterday. Didn't see the first one though, pretty sure the engine doesn't have it fitted.

If the oil guide plate is not there Ash, you were lucky to get away with just the bearing. I have done a couple that the needles have got so hot that they were burnt and the shaft had to be replaced. The oil guide plate holds the oil long enough to lube the roller bearing.

[AshimotoK0]

Have come across this problem with the needle roller on a couple of the early 500K0 engines. Check to see if you have these parts fitted : oil guide plate 23106-323-000 and bearing plate 23102-323-000. The ones I had needle roller problems never had these fitted.

Got the 2nd item Graham as I remember taking it off yesterday. Didn't see the first one though, pretty sure the engine doesn't have it fitted.

If the oil guide plate is not there Ash, you were lucky to get away with just the bearing. I have done a couple that the needles have got so hot that they were burnt and the shaft had to be replaced. The oil guide plate holds the oil long enough to lube the roller bearing.

The guy in York who advised James and then me on the early case VIN's reckoned that there was an inherent gearbox problem that probably 'saw off' a lot of those 1st issue bikes. Maybe that was it Graham? It just proves that with these old bikes that it's prudent to give the engines a full strip down just to be on the safe side. I suppose with a 2-stroke that goes without saying but a lot of people I think believe you can just get a low miler 4-stroke  import from DK, ultrasonic the carbs and away you go. That camchain tensioner with PTFE pad slipper on the guide looks like the best design of tensioner I have seen on a Honda. Or does it have it's own problems?