Measuring O-Rings

[Oddjob]

I remember that day well, I took the missus with me and was on my K reg 500 which I had fitted with an oil pressure gauge mounted about the clocks, along with a volt meter and a digital clock (yeah, really) on the motorway doing about 70 I noticed the oil pressure suddenly drop, the oil light flickered on and off a few times and the engine just sort of stuttered, then the pressure came back but not as high as before. I stopped, checked the engine over but couldn't find any leaks, the oil light now flickered on tickover which it didn't do before. As we were close to Derby by this point I decided to carry on but keep an eye on the engine and the pressure just in case. I got all the parts I was after at Palins by asking for the parts themselves not the numbers, there were so many he asked if I wanted to buy a used parts book for £5, I nearly kissed him. Limped home on the A roads and found the oil filter had collapsed, like someone had wrung it out to dry, the paper was spiraled. Pattern filter not genuine. Replaced it but still low pressure, replaced the oil pump, still low. Eventually I took off the sump and the mesh filter was almost totally covered by paper fibres from the inside of the filter, scraped that off and it was fine after. The pressure relief valves must have worked that day. Never used a pattern filter again after that.

[McCabe-Thiele (Ted)]

Great Letter Head  Ash - you can see just what a multi-franchise dealership they were back in the day - 12 brands!

Oddly enough  most of my Honda Spares I bought from Samways when they were on the corner of Mill Street/Nuns Street - now a Sainsburys Local Store.
Samways were on my first Derby foot beat so on nights I would dream of one day owning a CX500 as I gazed at the new & used bikes circa 1979.

.https://www.google.co.uk/maps/@52.9258175,-1.4897484,3a,75y,90t/data=!3m6!1e1!3m4!1sUSyRnxApkW0FOqRG9ynG5A!2e0!7i16384!8i8192?entry=ttu

 

[Laverdaroo]

Roo can remember the 1880s but not the 1980s Ted.

You've met Roo Ted, is he a spritely 80 year old or a really knackered 70 year old would you say.

 A shagged out 50 year old!

[McCabe-Thiele (Ted)]

You've met Roo Ted, is he a spritely 80 year old or a really knackered 70 year old would you say.

I think as one ages you can identify with folk your own age but youngsters all look the same- tbh I thought Roo was in his late thirties or early forties.

I have been paid handsomely to make this unbiased statement from his features on the 10th September 2022 when he delivered my current money pit. 

[AshimotoK0]

Trying to identify 500 top end o rings. Ken ..is this everything. There is also weird tiny one which may just be a bit of flash or rogue part.

[Oddjob]

Never seen the orings for the head in green, the valve stem rings were green though. One of the 11 x 2.5 rings is for the tacho drive but not sure without looking where the other 2 are used.

Small one doesn't belong. Looks like a carb ring.

Tappet covers are 30.8 x 3.2mm.

the 2 oil control valves are the bottom of the barrel for the other 2 x 11 x 2.5mm rings.

Looks complete Ash. Missing the valve stem seals you get in a genuine kit though unless you didn't show them as they aren't orings.

[Bryanj]

Cam chain adjuster bolt i think, the top one has a crush washer the adjuster an O ring under the normal washer, check the size in the 500 book in cave

[Oddjob]

The camchain adjuster is the 5.8 x 1.9 one.

[AshimotoK0]

'O" rings are from the kit you kindly sold me when I 1st bought the bike off James, Bryan .. the complete one with the yellow cardboard packing. It didn't include the stem seals..so I bought those separately  online and are already fitted. I also got a genuine bottom end set a year or so later in a job lot of gasket sets (already detailed earlier in this thread).

[Bryanj]

Still got some of those for mine, didnt realise there were no stem seals, sorry Ash.
Stumped about the O ring then, cant think of any other small ones

[AshimotoK0]

Still got some of those for mine, didnt realise there were no stem seals, sorry Ash.
Stumped about the O ring then, cant think of any other small ones

No problem mate ... that set was a bargain quality one .. stem seals or not.
I wonder what the green ones are made from ... probably  something with superior properties to standard nitrile rubber. Possibly some kind of fluoro-elastomer.

[Nurse Julie]

They are silicone Ash.

[Oddjob]

Probably specced as silicone due to the high heat those rings would be under connected to the valve stems. The valve stem seals seem to be made of the same stuff, most of mine are green as well although some are black.

[Oddjob]

After much searching I managed to find a CB500K parts book in America, printed May 1971. A little haggling over the price ensued and it eventually dropped through the door today. The odd thing is that it is half size from my other book. My old book is about A4 size, this is much smaller. The carb diagram is a fold out affair but doesn't include oring sizes, the back however does have the complete list of part numbers like the UK version.

Very odd.

[Oddjob]

You got me thinking Ken. Where are the part numbers for the complete gasket sets listed? You don't see them in parts books AFAIK.  Dont forget also that you can earn £1k in eBay sales before it's deemed as taxable. At least I believe that is the case. Mick Taylor ( kettle738) told me about it.

Spotted this today Ash. You might find it interesting, it's on the back of the card of the 5 bottom end gaskets set I bought.