Measuring O-Rings

[Oddjob]

I was looking for something else yesterday and found 2 old oil pumps for the 500/550 lying in the bottom of a huge box, I decided on a whim to restore them, both were complete except one has one of the small collars missing that have the bottom O-Rings around, will probably find one of those somewhere. So I took them apart and cleaned them both up, must say they cleaned up very nicely. However the O-Rings will need replacing so I decided I'd see if I can find them without having to buy genuine Honda. After recently seeing a tappet cover O-Ring provided by an Ebay seller which claimed to be a perfect replacement for a genuine Honda O-Ring and finding it so bad I couldn't trust using it, I decided this time to source my own. The problem though is that Honda are kinda sparse with the info for the oil pump, the pressure relief valve (both of which were stuck BTW, that's both oil pumps and 3 filter bolts now where the relief valves are stuck, that could be from standing so long, they've been in that box since before 1980 I reckon) is the only one listed with it's full info, 19.4 x 2.8mm. Honda state the big O-Ring is 47mm but no section is listed. Same for the 2 collar O-Rings, just 14mm is listed, no section. The O-Ring under the cap isn't even listed as being available and it isn't included even in a full genuine Honda gasket kit so that will require some thought.

I looked online on advise on how to measure an O-Ring, looked easy enough but nope that didn't work. The 47mm O-Ring now measures 52mm, the 19.4mm is the closest to being correct at 20mm, the 14mm is now 15mm. The other problem is, if the diameter has changed so has the section, being squashed distorts them over time. I measured them all and wrote down what I thought they were, then I remembered having a genuine bottom end set in the loft, so that came out and I measured a brand new non distorted O-Ring and they were quite different. None of the measurements I'd carefully taken were correct, which means the one not even listed will have to be carefully thought about. It's now a loose fit on the top of the pump, it fits inside the cap just fine but there doesn't seem to be any compression taking place when the cap is fitted with the old O-Ring, I reckon it must have been a tightish fit around the flange on the top of the oil pump when new, it must be slightly taller than the flange as well or it wouldn't seal too well.

So now I have some on order, I've done a few choices for the cap O-Ring, I'll see which one I feel is best.

One word of caution on buying none genuine Honda O-Rings, first off they are all nitrile rings (AFAIK) and unless the ring comes into contact with petrol that should be just fine to keep using. Viton is usually harder to compress, not a huge difference TBH, a normal ring is 70 and Viton tends to be 75 or 80. A number of the genuine Honda rings are also really odd sizes, that can normally mean they aren't available to buy from a UK manufacturer, the tappet cover is one, which is also the same ring as the inlet manifold rubbers, on a tappet cover is not absolutely vital to get a perfect seal but on an inlet manifold that's another matter. The one I was given to fit was so bad I ended up robbing an old one from a tappet cover and fitting the new one there instead. You cannot buy these rings off the shelf, you have to have them made specially and the minimum order is normally 500. It's the same for the pressure relief valve cap on the oil pump, it's such an odd size they don't make it anymore. Incidentally it's also the same ring that fitted to the 3 oil gallery bungs in the crankcase, that's why there are 4 of them in the gasket kit. You'd need to order 500 specially to get a perfect fit, that can be expensive.

I'm in contact with a large UK manufacturer of O-Rings about getting some rings specially made for me,  tappet covers and inlet manifolds will be one, the relief valve and oil gallery plugs will be another if I feel my replacement doesn't fit the bill well enough.

[Orcade-Ian]

Ken,
Not sure if this might be useful but many years ago I wanted to re-furbish my Lake and Elliot Trojan trolley jack which was failing due to deterioration of seals (I bought it new in the early 80's). My seals were special and most places needed an order of 1000 units.  I contacted Barnwell services in Birmingham and they made some for me.  Might be worth a call or email
(web site http://www.barnwell.co.uk/) They were very helpful and not expensive either.

Ian

This is the story of the jack

http://www.stallard-engineering.co.uk/stories/other/Trolley%20Jack.htm

[Oddjob]

Just checked the site Ian and nothing close to what I need, Honda didn't seem to use normal sizes, they seem to like restricting you to buying theirs at inflated prices.

Nice try though Ian, thanks. I may contact them to see if they can price up some specially made ones though, depending on the price I get from my other source, who BTW are very big in manufacturing them. Their range is very big and even they don't stock the ones I need in most cases.

[Bryanj]

Ken, long time ago now i had an oil pump cover leak and spent some time at Dowty seals working out what to use and came up with 46x2 as a size which stopped the leak.
Thicker holds the cover too far off and pressure drops, smaller leaks.
There is  honda O ring that size used in a Goldwing.

I have a very early parts book that gives O ring sizes, even the carb seperate ones with sizes and part numbers.

[Oddjob]

I've measured the flange that's on the oil pump Bryan, as far as I can work out it's somewhere between 43 and 44mm, 43 being maybe just a midges too small and 44mm a midges too big. The flange height is hard to judge but 1.6 to 1.7mm is my best guess. I'm trying 3 different variations of those sizes to see what I feel would work the best, 46mm I'd say would be the internal size of the cover which sits on top of the flange and 2mm I would say would be just a fraction too big in section, 1.8 or 1.9mm would be my guess of the ideal section.

I'd love to see that parts book Bryan, never even heard of that being around, saying that I bet the partsman knew about it. If you have a copy of it anywhere please send it to me.

[Bryanj]

Its an early US one Ken, not sure if its the one i scanned, if so wiĺl send you a dvd, just checked and its the K1/2 500 parts in Ash's dropbox with my name on it, not the JDM one

[McCabe-Thiele (Ted)]

Ken,
Not sure if this might be useful but many years ago I wanted to re-furbish my Lake and Elliot Trojan trolley jack which was failing due to deterioration of seals (I bought it new in the early 80's). My seals were special and most places needed an order of 1000 units.  I contacted Barnwell services in Birmingham and they made some for me.  Might be worth a call or email
(web site http://www.barnwell.co.uk/) They were very helpful and not expensive either.

Ian

This is the story of the jack

http://www.stallard-engineering.co.uk/stories/other/Trolley%20Jack.htm

Your Jack story reminds me of my first trolley jack a used Bradbury that I bought back in 1978 for  £40  with a slight creep. Local motor factors fitted new seals that lasted until around 1995 when the creep returned. Repaired again for by a mates contacts foc. It gave out completely about 5 years ago. Ended up with a CostCo replacement that is about a quarter of the weight.

[davidcumbria]

Great resource that Bryan parts list. I need a replacement o ring for the gallery  plug behind the alternator. £13.60 delivered for one from DS. ( you must be shitting me) If the size is correct in Bryan’s part list £2.80 for five free delivery on eBay. 

[Oddjob]

Cheaper here David.

https://www.ebay.co.uk/itm/293213824316?hash=item4444e7e53c:g:eD8AAOSwz6Bdb7yV&amdata=enc%3AAQAIAAAA4MsAP9ribbu6qNn%2BAzCFoCoIM8V0xhO6Sq%2BEGAlhMqWAU9E94lo%2Bxyzho6AEPib9W6APtLnHydKb%2FEJt7uUhTYArP9ZprxbwXbIr6dZTvOa7LPh%2BegaTQFrWLoVQ3GKy8mkRJXdELFF4j%2B%2FdhBDVSTs6l35MjBf0xj7cv9BNRa%2FU6xSho6vDkEcCcwzNMOTCkm5C%2Fw9OI%2Brpq6AZYZycEvKdXL%2B9fS7WUBEjJbTGEJTOuyp%2BmuZCRGLUaE35Zz1ktEZDWaGGNbjX4uS6aUhYAWZ155huFOhixBkdR5zmo7GH%7Ctkp%3ABk9SR_qUvL6aYg


Looked at that list Bryan, interesting. It doesn't however show the ring behind the oil pump cover and lots of the others are still missing parts of the sizes, tappet covers for instance are still shown as 30.8, no section, as are the 2 on the pump and quite a few others. The float bowl drain screw is also missing the section. I wonder if Yamada (makers of the oil pump) is still in business? a quick email to them would solve the question, if they answered of course.

Seems they are, sent them an email, lets see if they reply.

[Oddjob]

O-Rings arrived today for the oil pump. The difference between the old and the new when laid side by side or over the top of each other is noticeable. I got 3 different sizes for the O-Ring under the cap and the one I thought it would be wasn't the best fit. It did fit but wasn't to my liking, I think I've got the clearance bob on, with the cover laid in place with no O-Ring fitted and it turned you can hear metal to metal contact, with an O-Ring in place you cannot so it's clearly holding the surfaces apart.

I'll send a complete set to a mate who's running this type of oil pump and ask him to test them to see if they leak. As the large O-Ring and the smaller dowel O-Rings are the exact size I'm not expecting any problems, the relief valve one is also a very good fit but is a close size not the exact size, that should be ok but I've got a quote for some specially made the exact size needed and the price difference is 2p so might as well go for the exact size, it's the cover ring I want to check, just to be safe.

If they work as expected I'll sell a complete kit for the 500/550 oil pump for £10 inc P&P.

If anyone wants some O-Rings for the 3 oil gallery plugs on the lower crankcase, I'll be selling them as well (not the one behind the generator, that's a different size, 91319-300-000, 8 euros at CMS, £9.94 at DS), part number 91315-044-000, seems to fit all the fours. CMS are charging £2.06 each, DS £2.04 each, plus P&P which we all know makes these bloody expensive if that's all you need. I'll do all 3 and include the one behind the generator so all 4 for £6 inc P&P.

I'll also being having some tappet cover and inlet manifold O-Rings made, the EXACT size, not as close as you can buy off the shelf like most Ebay sellers, 8 for £5 inc P&P or 12 for £8 inc P&P. I'll let you know when all these offers are available.

[davidcumbria]

That’s great Ken. I’ll definitely be in the market for the oil pump and tappet cover rings

[Trigger]

O-Rings arrived today for the oil pump. The difference between the old and the new when laid side by side or over the top of each other is noticeable. I got 3 different sizes for the O-Ring under the cap and the one I thought it would be wasn't the best fit. It did fit but wasn't to my liking, I think I've got the clearance bob on, with the cover laid in place with no O-Ring fitted and it turned you can hear metal to metal contact, with an O-Ring in place you cannot so it's clearly holding the surfaces apart.

I'll send a complete set to a mate who's running this type of oil pump and ask him to test them to see if they leak. As the large O-Ring and the smaller dowel O-Rings are the exact size I'm not expecting any problems, the relief valve one is also a very good fit but is a close size not the exact size, that should be ok but I've got a quote for some specially made the exact size needed and the price difference is 2p so might as well go for the exact size, it's the cover ring I want to check, just to be safe.

If they work as expected I'll sell a complete kit for the 500/550 oil pump for £10 inc P&P.

If anyone wants some O-Rings for the 3 oil gallery plugs on the lower crankcase, I'll be selling them as well (not the one behind the generator, that's a different size, 91319-300-000, 8 euros at CMS, £9.94 at DS), part number 91315-044-000, seems to fit all the fours. CMS are charging £2.06 each, DS £2.04 each, plus P&P which we all know makes these bloody expensive if that's all you need. I'll do all 3 and include the one behind the generator so all 4 for £6 inc P&P.

I'll also being having some tappet cover and inlet manifold O-Rings made, the EXACT size, not as close as you can buy off the shelf like most Ebay sellers, 8 for £5 inc P&P or 12 for £8 inc P&P. I'll let you know when all these offers are available.

Seems a lot of effort when, Nurse Julie already sells all these o'rings cheaper with a 10% discount to forum members for 10 years now.

https://www.ebay.co.uk/itm/166185519025
https://www.ebay.co.uk/itm/166185952380
https://www.ebay.co.uk/itm/166025470941

And most engine single o'rings

[Oddjob]

I don't think any effort I make to get a better deal for the members is a LOT of effort, yes it's some effort and TBH I doubt I'd have bothered except for a recent experience when I went to fix another members bike, FOC I might add, he paid for petrol and parts, all my labour was free and it was considerable I may add.

His problem was his carbs, the bike was hard to start, ran poorly and was generally a bitch to get running. A lot caused no doubt by the fact he had the wrong carbs on, he had the carbs used on the continent, with smaller jets and a snorkel needed etc. He had a spare bank of 627B carbs and I offered to completely strip and restore them for him, free. That's a LOT of labour. However I'm not in this game to make money, if I do it's a bonus but I don't let the pursuit of money rule my life, I saw a member struggling and offered to help, on the proviso that he didn't say anything on the forum, I didn't want everybody and his dog taking advantage of my good nature. So we met and the carbs were handed over, I had the lifter rod hard chromed as it was pretty rusty, the carbs were painted, the jets were all wrong, a real mixture of sizes, the needle clips were in different places, the mixture screws weren't set right, all in all the bank was a mess and someone had clearly been fiddling without knowing what they were doing. I heli-coiled all the stripped threads in the float bowls, sourced new genuine jets, cleaned everything up, polished the float bowls and carb tops to within an inch of their lives (and we all know what that means with me), had all the bracketry and everything unique zinc plated by another member on here as my kit is still in storage, in short when they were done they were as good as perfect, better than Gerbens if I'm honest.
I fitted all new Viton orings, which he provided, I compared them to a set I still have for mine off Gerben and noticed differences, not knowing which was correct I fitted them as the job needed to be completed.
I then travelled 125 miles to fit them and service his bike at the same time, this proved to be a very wise move as the bike was pretty bad TBH, it ran like a slug, wouldn't rev, wouldn't go, flat as hell, hard to start, hard to rev. Horrible. We did the tappets, checked the timing even though it was electronic, it was out, so that was fixed. Did the camchain tension. Then went to fit the carbs, I'd asked him to buy some new inlet orings as I wanted to be sure they were sealing, he had them in a small bag. However when we went to fit them we found they were such an appalling fit I didn't think they would seal, not wanting to chance that as it means removing the carbs again to change them I decided to use an old tappet cover oring instead, that's how badly they fitted, so we fitted the new orings in the tappet covers instead as they are easy to change afterwards.
Now clearly that shows that suppliers of these parts are not supplying the correct sizes, this concerned me as I know how critical the inlet manifold seal is to the good running of the engine, anyone finding the engine racing etc after fitting these would probably discount them as the cause as they were new.
So I decided I'd do something about that, enquired about having some made the correct size, not close, not within spec, the EXACT size as stipulated by Honda, that's 30.8 x 3.2mm not 30 x 3mm or 31 x 3mm or any other variation of those numbers, any member can search for those sizes and they'll find they aren't made, if you want that size it's a special order with a 500 minimum order. Now that gets expensive, especially when you factor in what the closest oring to it costs in comparison, double the price in fact. Same goes for quite a few other orings that Honda list, they used odd sizes and they just ain't available off the shelf, you can get close but not exact. So whilst I was talking with the UK largest manufacturer of orings I got some other quotes at the same time, I thought lets see if I can source all the hard to find ones. So all the carb Viton rings, got quotes for all of those, the oil pump, got quotes for those. Now I know what they cost and I checked to see what they were selling for on Ebay. And then I realise how much they are overcharging, over 500% on most of them, a ring that costs 13p is marked up to 90p in some cases and that's one of the cheaper ones and it's the wrong size which makes it really poor value.

So, a lot of effort, not really , few emails, a little searching and the desire to see people get value for money.

I did notice BTW that all your Ebay links are now significantly cheaper than they were yesterday, competition, it's a bitch isn't it. I can in fact go much lower with my prices, I don't mind not making any profit, I can also significantly expand my range, I have hundreds of orings lying around, I tend to buy them in 20s or 50s when I buy them so I've got loads spare. Dipstick, 550 clutch adjuster, petrol tap ones, starter motor ones, camshaft end cap ones. I may even start doing some carb overall kits in Viton, perfect sizes.

I should also point out an error in your post, Julie joined Aug 2014. That's not even 9 years ago never mind 10 and she didn't start selling anything until she joined up with you. Maybe 5-6 years I'll give you that.

Now please don't post on my threads, you're not welcome.

[Nurse Julie]

I haven't lowered my prices Ken, Graham put the links on to the Nitrile kits I sell, but I also have the kits advertised in Viton which are more expensive.

[Oddjob]

They were £5.99 yesterday Julie and £4.99 today. There was no listing for the oil pump that didn't include the 3 screws, now there are 3 and they are £5.99 when the one with 3 screws is still £12.99, £7 for 3 screws is expensive, especially when they say JIS and there is no dot on the head.

Odd as well that when I first muted the point of having the tappet cover orings specially made in Viton http://www.sohc.co.uk/index.php/topic,25917.msg247649.html#msg247649 you stated that it was too hard and wouldn't crush down properly,  this is your response. Viton is too hard and won't seal properly on tappet and inlet manifolds. Honda did them in Nitrile for a reason. On ebay I sell the tappet O rings for £5.99 for 8 with free post and inlet O rings for £3.99 for 4 Inc free post. I buy them in bags of 1000 at a time. Note the price as well. Also note that in 2021 I was wrong in saying they were 30.8 x 3.0mm, they are not. It was only measuring one out of a genuine Honda gasket kit that I noticed this error, when fitted side by side in the inlet manifold you can see the difference between the 2 sizes. Ones a genuine Honda one and one isn't. Close isn't it but what I failed to take a picture of is how much the genuine protrudes from the groove, without that extra 0.2mm you don't get a great seal IMO. As you said in your comment, Honda made them in Nitrile for a reason, they also made them that size for a reason.

I know because Graham has told me in the past that he sometimes uses your account to post comments, so I'd ask that you don't post on my threads either.