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Friday, 5 November 2010

A Triumph of motorcycle design (not)

Modern Triumph motorcycles, along with most other modern bike brands are the epitome of good engineering.  The generation of riders who have grown up with modern bikes quite rightly expect high levels of reliability, but it wasn't always like that, oh dearie me no! Teeth-gnashing and loss of temper was a regular occurrence for the old farts among us.  At least we all became mechanically and electrically competent as a result of it all.

"Electrickery" problems were legendary and manufacturer Joseph Lucas wasn't called the Prince of Darkness for nothing.  However, it was a recent post about lubricants on a Triumph forum which took me back to the 60's when training as an engineer. Triumph motorcycles were my sole form of transport and as such, reliability was paramount to get me to lectures (and more importantly, the pub) in a timely manner.

Now, Triumph in particular produced some of the earliest oil-cooled engine designs on the planet.  At least, I'm assuming that was the main reason that there was more oil on the outside of the engine than sloshing around the internals, although woeful seal design could well have contributed!  The old joke about the first after-market accessory Triumph owners bought being a large drip tray wasn't all that far from the truth.  Anyway, I digress.....

Oil leaks aside, Triumph twins were pretty sound mechanically although there was one little device on them which had the potential to cause mayhem for the unwary.  Let me introduce you to the Oil Release Valve and Indicator:

 It served 2 main functions apart from the unintended one which I'll come to shortly.  The first function was as a pressure regulator for the lubrication system.  The second function was to visually demonstrate that the engine actually had oil pressure and wasn't about to lock solid and chuck the unfortunate rider up the road.  The photo below shows its location at the bottom of the timing gear cover on pre-unit construction Triumphs.  Later models saw it located on the engine block just in front of the timing cover.

 Location of the valve on a pre-unit construction Triumph

When the engine was running, the oil pressure lifted the cruciform-head screw (shown on the first photo) clear of the body to reassure the rider that the bike did indeed have oil pressure so that he or she could then concentrate on worrying whether the electrics would fail before reaching the intended destination.  So what's wrong with that you may ask - an enlightened bit of design, surely?  Well..... no, actually.

From the line drawing below, you'll note that part #5 is a piece of rubber tubing which slips over the indicator shaft to prevent hot pressurised oil from making its escape from this particular location.  Those of a cynical nature or legal persuasion will note the word "should" on the second line rather than the more reassuring word word "will" in terms of maintenance requirement.  In horse racing terminology, this wording must be equivalent of Triumph having a dollar each way, and with good reason.


The problem was that in the environment it worked in, the rubber sleeve had a limited life before it perished or split, pumping hot oil out onto the rider's right boot.  At least Triumph riders had one dry sock in heavy rain, which I suppose was the only (unintended) good thing to come out of an engineering cock-up.  A close friend and I both owned Triumphs which waterproofed our right-hand boots every 6-12 months.  There was no real risk of running out of oil when this happened as the smokescreen from oil pouring onto a hot exhaust pipe was a fair indicator that something was amiss, even to the visually challenged.

Why Triumph shifted it to the front of the engine on later models is a bit of a mystery.  To see if the indicator was actually working required quite a forward stretch combined with a downward focus - not exactly an OSH-approved riding posture when tearing up the highway!  Also, although an oily boot was a thing of the past, oil now streamed round the crankcase and the slipstream neatly redirected it onto the rear tyre, adding another interesting dimension to already indifferent cornering.  After a few decades, Triumph came to their senses and did away with it altogether.  Only a tiny component but perhaps indicative of resistance to change and the eventual collapse of the British bike industry.

Who'd have thought that one tiny component would have been the subject of a (slightly) tongue-in-cheek bike blog?

As an aside, I still have 2 pristine Triumph manuals which are an endless source of amusement, particularly in terms of their earnest optimism.  I may share more from their pages in the fullness of time if I continue blogging...

18 comments:

  1. ......if i continue blogging.......? Wouldn't be the same around here with out you Geoffrey!!!!!

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  2. Roger:
    Only started blogging when I was round home a lot looking after Jennie following her hip op, just to fill in odd gaps in time and to learn something new. That time is long past.

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  3. Geoff:

    " ......if i continue blogging.......?

    What is this nonsense !! do you not think that we hang onto your every word and you just snuck it in and thought we wouldn't notice ?

    another thing . . . just because we don't always leave comments doesn't mean we didn't visit. so get this notion out of your mind or we'll have to come over and smack you around

    bob
    Wet Coast Scootin

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  4. Geoff:

    PS: is 2011 your Cowichan Bay year ? I'm working on my trip planning . . .

    bob
    Wet Coast Scootin

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  5. Well, Bob my old friend... talk about everyone biting!! I think that Canajun summed it up rather neatly in a past post in that he blogs primarily for himself. That's the case for most of us I suspect. The reason for me having a go at blogging in the first place has long since passed so I'm perfectly relaxed about stopping and just going riding (as soon as my leg permits!), no big deal at all.

    No concrete plans yet for visiting Canada. Vietnam is still unfinished business. Decisions, decisions.....

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  6. Geoff,
    I wouldn't mind if you could continue posting some pictures every once in a while to keep my memories awake. Hope to meet you and Jennie next year in person! Plans for this are in the make...

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  7. Sonja,
    Sounds like your employers have had a change of heart in sending you to far-flung places. Excellent news and looking forward to it!

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  8. Geoff,
    I hope you continue blogging because you definitely have all of the qualities necessary - riding, photography, writing, beautiful NZ scenery.

    Bobskoot is right, as usual. I use to live or die by the number of comments on a post. I got discouraged by that. He gave me the same quote that he stated above. I know you didn't make the point about comments but sometimes I think it has an affect on how we judge the value of our posts. Personally I've come to realize that readership has more value than comments.

    I'm reading your posts and enjoy your take on things as well as your knowledge and experience on riding. Please don't stop now!

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  9. Mike:
    Thanks for the kind comments. I'm more with Canajun in just doing it for my own fun. Comments, either critical or positive are fine but they genuinely don't affect whether I write or not as there have always been plenty. Whether it's the fact that my leg is still stopping me from riding or that I feel like I haven't got anything fresh to say will no doubt reveal itself in due course.

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  10. Geoff, I have read every one of your blogs and have really enjoyed them. You do seem to have a gift for it! I do hopeyou carry on but as I have found recently, times and situations change! Whatever you decide, keep on riding!

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  11. Thanks for the kind words SB - continuing riding when the darned leg heals is a racing certainty!

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  12. Geoff, my bro' in NZ:

    Lately I have gotten back into Photography. It all started to rear its head when I purchased my new camera for my big trip. I have been doing enlargements, getting to know PS (Photoshop), and I have even purchased a new printer and some other goodies at the camera swap meet yesterday. I even got my framing supplies out. for the past couple of weeks I have been going through my photography forums and sort of ignoring the Blog. Right now I'm so busy I have no time . . . it's not from lack of content

    bob
    Wet Coast Scootin

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  13. Geoff:

    PS: I think I am going to adopt more of a Diary format, modeled after my buddy (Key West Diary) and just include everything that rumbles in my mind. Whether it be riding, photography or something else. You're right, it has to be something you do for yourself and if others are interested then that's a bonus, but I do enjoy having friends in the blogging community whom I hope to meet - one day

    bob
    Wet Coast Scootin

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  14. Can the Oil Release Valve Indicator rubber sleeve be replace with a plastic tube or something else or even be left out completely? I am thinking of using hospital type breathing tube that fits to the mask. This fits snugly over the shaft. If not is this rubber available loose? Or is there some thing else that can be used?

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  15. Hello Anonymous,
    I guess that technology has improved immensely since the first oil release indicator rubber material so the answer is almost certainly. The first photo in this post of the indicator assembly is of a BRAND NEW one which I found on the internet. I presume these new ones have been specifically manufactured to overcome the problems of the old ones. I doubt that they'd be very expensive so tracking one down would probably be your best option as the manufacturers may have improved the whole internal design.

    Hope this helps.

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  16. Anonymous:
    A quick perusal of Google Web Images led me to this website who make upgraded oil pressure indicators for Triumphs: http://petersclassicbikeparts.nl/contents/en-us/d152_02.html.

    Cheers,

    Geoff

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  17. Hi, Have any idea where l can get replacement pressure release valve rubbers. Regards Phil

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  18. Phil, I have no idea where you live so can't be specific but if you're not a member of the Triumph international website try www.triumphrat.net as they ate fully international and someone can advise you.

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