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Re: 1928 Ariel Model C [Re: Magnetoman] #752246
10/11/18 12:03 am
10/11/18 12:03 am
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New Jersey USA
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"As an aside, we're discussing whether the correct valve geometry would have the force from the lifter parallel to the valves when they are half-way, or fully, open. Not that it means it's correct, but it's interesting to note that the composites in my earlier post yesterday show that, assuming the original valves also were 4" long, Val Page thought the guides would have minimum wear if the force were parallel to them when they were closed."

Yes--that is interesting.
I can see rationales for the normal position to be at half lift and at full lift but not at zero lift.
Val Page is one of the giants of motorcycle engine design but maybe even he had feet of clay (ora couple of toes anyway!).

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Re: 1928 Ariel Model C [Re: Magnetoman] #752252
10/11/18 12:33 am
10/11/18 12:33 am
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I don't think the vectors you have drawn have anything to do with the issue at hand. As you said, it is the friction between rocker and valve tip that brings about the sideways force. If you freeze the geometry at any moment, there is no side force. It is only relative motion of the surfaces that produces side force in the dynamic situation.

IF during valve actuation the surface of the rocker simply "rolled" over the surface of the valve tip (ie without sliding), there would be no sideways component of force imparted to the valve.
This would be true if the contact "line" between rocker and valve tip moved equally with respect to both of their surfaces (the distance across the flat valve tip and the distance around the curved rocker surface). There would then be no involvement of friction to impart a sideways force, which only arises when one surface is sliding over the other.

I reckon what is important is to get the best rocker profile to acheive minimum sliding between those surfaces. Almost certainly there will need to be a compromise (ie most sliding at some part of lift).

This is where my brain turns to mush, because on first view I'd agree with TM that the scrubbing force will be higher at higher lift, but of course with your high revving Ariel and the aggressive cam opening profile, the inertia of the valve may be a complicating factor? That would require analysis beyond myself, but...?

On a general observation note, it does seem as though the rockers were only working on their inner halves with lash caps. Removing the lash cap looks as if it may have allowed the inner edge of the valve tip to be involved in early lifting. It is easy to understand how this could have ground through the hardening of the rocker to such a result. The OD of the lash cap was enough to prevent this happening. Is it possible both valves are (were) too long?

Re: 1928 Ariel Model C [Re: Magnetoman] #752255
10/11/18 1:15 am
10/11/18 1:15 am
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Originally Posted by Tridentman
Val Page is one of the giants of motorcycle engine design but maybe even he had feet of clay
He was only a youngster of 35 when he designed the Ariel engine. His K&E wouldn't have even lost its new slide rule smell by then so we should cut the kid some slack.

Because of the diameter of the wear pattern on the lifter we know it happened in the last ~1000 miles, after the lash cap had been removed. That many miles at 40 mph would have taken 25 hours, and the gearing gave ~2000 rpm, so the engine made 3M revolutions, and the exhaust valve opened and closed 1.5M times. As the photo shows (open on left, closed on right), each time the valve opens (and closes) the rocker slides across the top by about 1/3 the diameter of the valve stem, i.e. is slides by 2x1/3x0.34" = 0.23" in one open/close cycle. So, in 1000 miles the rocker and valve slid against each other 1.5Mx0.23"= 5.4 miles and in doing so plowed a furrow 0.15" deep.

If the material removal had been constant over those 1000 miles then 0.15" (0.38 cm) removed divided by 3M back-and-forth movements = ~13 Angstoms /movement. That is, each time the valve opened the sliding removed a layer of ~4 atoms, with another ~4 atoms when it closed. Although that's very little material, it added up.

Attached Files LiftersOpenClosed.jpg
Last edited by Magnetoman; 10/11/18 1:43 am. Reason: fixed open/closed switch
Re: 1928 Ariel Model C [Re: Magnetoman] #752257
10/11/18 1:38 am
10/11/18 1:38 am
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I think it's actually open on left, closed on right, but primarily it shows the "one sided-ness" I was referring to, and the vulnerability of the edge of the valve tip.

Re: 1928 Ariel Model C [Re: Magnetoman] #752258
10/11/18 1:46 am
10/11/18 1:46 am
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That the contact between the rocker and valve tip moves isn't the same thing as saying that it slides, sliding being the important consideration.

Re: 1928 Ariel Model C [Re: koan58] #752259
10/11/18 1:48 am
10/11/18 1:48 am
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Originally Posted by koan58
I don't think the vectors you have drawn have anything to do with the issue at hand.
Yes they do.
Originally Posted by koan58
It is only relative motion of the surfaces that produces side force in the dynamic situation.
No, that's incorrect. I'm not done with the subject so maybe future posts will make the situation clear.

Re: 1928 Ariel Model C [Re: Magnetoman] #752262
10/11/18 2:01 am
10/11/18 2:01 am
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Thanks, I always look forward to your illuminations.

Good on you for what you achieved, and such a great log to have it all from start to ... Not end yet with this health check (not a PM!).

Can't wait.

Re: 1928 Ariel Model C [Re: Magnetoman] #752408
10/12/18 2:16 am
10/12/18 2:16 am
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In preparing to repair the lifters with Stellite I first "repaired" them with Photoshop. As can be seen if I grind a larger radius surface it would make contact about 1/3 of the way across the lash cup when the valve is closed, and about 2/3 of the way across when open. This will require adding some material at the tip, which I will do with low carbon ER70S-2 welding rod to bury the cased-hardened surface. Stellite doesn't like carbon and will crack unless it is deposited at an appropriately-high temperature that depends on the % of carbon. After grinding the profile in the ER70S-2 I'll add the Stellite at a high temperature despite the lower carbon content, just to be sure.

Attached Files LifterSimulatedProfile.jpg
Re: 1928 Ariel Model C [Re: Magnetoman] #752432
10/12/18 11:41 am
10/12/18 11:41 am
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Quote
If the material removal had been constant over those 1000 miles then 0.15" (0.38 cm) removed divided by 3M back-and-forth movements = ~13 Angstoms /movement. That is, each time the valve opened the sliding removed a layer of ~4 atoms, with another ~4 atoms when it closed. Although that's very little material, it added up.


Surely you are not suggesting a linear rate of wear .
To come up with a conclusion like that you would need a MBA, mastering in inappropriate application of spreadsheets.


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Re: 1928 Ariel Model C [Re: Magnetoman] #752434
10/12/18 12:05 pm
10/12/18 12:05 pm
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Originally Posted by Magnetoman
Originally Posted by Tridentman
a) You compare the with and without lash cap pressures on the basis of areas but the contact between rocker and valve top/lash cap is much more of a line contact --so arguably the ratio should not be 1.76 but rather 1.33.
A line is only a line in geometry class. On my Ariel the line has a finite width so it's an area that matters. However, it's true that when the initial wear started the area was a fraction of the circumference times the linewidth, so it started out at 1.33 and moved toward 1.76 as the wear progressed.

Originally Posted by Tridentman
As the applied force is at a maximum at maximum lift due to maximum spring compression at this point then arguably one should aim for the rocker arm/ valve geometry to be normal (in line) at this point.
At the installed length of 1.68" the seat pressure is 87 lbs. The inner and outer spring constants are approximately equal (40 and 45 lbs/in) so in compressing them an additional ~0.35" at full lift that increases by ~0.35x85=30 lbs. (i.e. by ~34%) for a total of ~118 lbs. Anyway, minimizing the sideways thrust requires minimizing the deviation of that tangent line over the entire travel, and since the force is a constant-ish average of 102 lbs. I think that means the tangent should be parallel to the valve stem at the center of the travel.


I think 87 lbs on the seat is high for that bike. Was there a spec in the manual? We use 95 to 100 lbs on full race Triumph motors than turn 7500 RPM. What is redline on the Ariel? I would back it off to about 60 to 65.
I would also look at installing an oversize valve on the exhaust to catch a better and higher valve seat before replacing valve seat itself.

We went to Barber Vintage Festival and got to ride the Cannonball Nortons on the track for a half dozen laps. I did not want to get off the bike. Super fun!

Re: 1928 Ariel Model C [Re: Magnetoman] #752439
10/12/18 2:08 pm
10/12/18 2:08 pm
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Wisconsin, USA
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If the rocker was set up off to the side of the valve, so as to cause the valve/cap to turn with the drag caused by the rocker, would the turning/following of the rocker reduce wear, as it would reduce the area that the rocker would have to slide across?
Also as the valve would turn, would this reduce the pull of the valve against the valve guide?

Last edited by franko; 10/12/18 2:11 pm.
Re: 1928 Ariel Model C [Re: Magnetoman] #752444
10/12/18 3:05 pm
10/12/18 3:05 pm
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Originally Posted by BSA_WM20
To come up with a conclusion like that you would need a MBA, mastering in inappropriate application of spreadsheets.
Sorry, but I'm sticking by what I wrote. The estimate I gave provides a physical feeling for the amounts of material involved, also showing that even a tiny removal rate of a few atoms at a time adds up to something significant when you repeat it a few million times.

Originally Posted by RPM
I think 87 lbs on the seat is high for that bike. Was there a spec in the manual? We use 95 to 100 lbs on full race Triumph motors than turn 7500 RPM. What is redline on the Ariel? I would back it off to about 60 to 65.
The almost complete lack of technical information means I've been feeling my way through this rebuild from the start. One of the reasons I post all the technical details I measure myself is in case someone, like you, sees in them something worrisome.

Ariel doesn't give a figure, but I infer from their literature that they considered ~5500 rpm as redline. I'm using springs supplied by the Owner's Club, but that by no means says they're correct. However, seat pressure is only part of the story, with spring constant and lift the rest of it. What keeps valves from floating is the pressure from the springs when compressed to the full lift value and that pressure for your Triumps' springs might -- or might not -- be much higher than that of my Ariel's, depending on their spring constants. Do you know what that full-lift pressure value is for the Triumphs? As for me backing it off, that's not really possible with the current springs without cutting pockets in the head to reduce the preload. I'd have to try to find replacement springs of the correct length, ID, OD and spring constants to give the desired preload as well as pressure at full lift, which wouldn't be easy.

Originally Posted by RPM
I would also look at installing an oversize valve on the exhaust to catch a better and higher valve seat before replacing valve seat itself.
After replacing the guide in your rolling shop we had to cut quite a bit of material from the seat, but the old guide was so worn that other possibilities for the problem with the seat didn't come to mind. However, the ~0.015" wear of the lifter during the subsequent 1000 miles should have resulted in that much additional valve lash. But, it didn't. I wiggled the lifter each time I greased it and the lash always was close to 0. The only way a groove ~0.015" deep in the lifter wouldn't have increased the lash by that same amount is if the valve had receded into its seat by ~0.015".

I'm not 100% sure the exhaust valve actually has receded into the seat (only 75% sure), but if recession is taking place due to modern fuel than installing a larger valve won't solve the problem. That's why I'm thinking of installing a hardened seat. But, it's fairly major surgery so I'm not rushing into this and am more than interested in advice on this matter.

The above reminded me that I might have given an incorrect answer for a measurement in an earlier post so I've added some text to clarify it.

Originally Posted by RPM
We went to Barber Vintage Festival and got to ride the Cannonball Nortons on the track for a half dozen laps. I did not want to get off the bike. Super fun!
What?! Does this mean you weren't racing on the Cannonball when I passed you? I thought it was my superior riding skill that let me get by the gaggle of side-valve Nortons each time I encountered them.

Originally Posted by franko
would the turning/following of the rocker reduce wear, as it would reduce the area that the rocker would have to slide across?
Even if it were possible to offset the rockers, reducing the contact area would increase the wear because the resultant pressure would increase. The fact the inlet rocker acting against the lash cap was fine after 3000 miles shows that the current geometry is fine. It's (presumably) the too-thin case hardening of the exhaust rocker after I reground it that caused the problem, in which case Stellite should fix it.

Re: 1928 Ariel Model C [Re: Magnetoman] #752450
10/12/18 3:43 pm
10/12/18 3:43 pm
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Farnham, Surrey, UK
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I know nothing about valvetrain geometry and how it's meant to work, however there is some guidance available on the web which seems to make sense, see This Link.

In essence, the idea seems to be that the ideal rocker to valve contact position is established by using a marker pen/engineers blue on the top of the valve/lash cap to determine where the contact point between the valve and rocker actually is and making adjustment to the pushrods/rockers as necessary. The photos of the rocker wear seem to show the rocker contact is too short.

Using new stellite or whatever hardened material on the rocker pads is clearly the best way forward to build up the rocker contact point and eliminate wear in future.

Just wondering what the cam and lifters look like after the 3K miles with Shell Aero Plus Oil ?


Last edited by gunner; 10/12/18 4:03 pm.

1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: 1928 Ariel Model C [Re: gunner] #752452
10/12/18 4:09 pm
10/12/18 4:09 pm
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Originally Posted by gunner
The contact point between the rocker and valve is meant to be in the centre of the valve top. The photos of the rocker wear seem to show the rocker contact is too short.
That's why I did the Photoshop reconstruction to determine where I need to add material to the rocker to have contact vary from somewhat on side of center to the same somewhat value on the other side.

Originally Posted by gunner
Just wondering what the cam and lifters look like after the 3K miles with Shell Aero Plus Oil ?
Patience, patience. I'm very curious as well, but I won't be diving into the rest of the engine, or the gearbox, until I finish with the head. I'm not facing a hard deadline this time so progress will be (even) slower than when I rebuilt it the first time.

Re: 1928 Ariel Model C [Re: Magnetoman] #752453
10/12/18 4:13 pm
10/12/18 4:13 pm
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Overland Missouri
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Keuffel and Esser, can't fool us!

Re: 1928 Ariel Model C [Re: old mule] #752454
10/12/18 4:27 pm
10/12/18 4:27 pm
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Originally Posted by old mule
Keuffel and Esser, can't fool us!
Valentine Page's engine design tools:

Attached Files DesignTools.jpg
Re: 1928 Ariel Model C [Re: Magnetoman] #752459
10/12/18 5:12 pm
10/12/18 5:12 pm
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Posts: 900
Farnham, Surrey, UK
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Back in the 70's I went to a High School in Kent whose pupils mainly went on to serve in Chatham Dockyard in various engineering or clerical roles.

The school was great as we had a dedicated classes for metalworking, woodworking and electronics. I remember having my own slide rule and Trigonometry/Algebra books. The best part was learning how to use a lathe/mill as well as brazing and wood working skills.

I'm sure I have my original slide rule hidden away in the loft somewhere but I'm not sure what reaction I would get if I was to show this device to current 18-20 year olds.

I guess in some ways it would be like comparing a navigational sextant to a gps device, however I note that navigation by sextant is now being retaugt by various militaries incase of gps failure, so its always good to have a fallback.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: 1928 Ariel Model C [Re: gunner] #752465
10/12/18 6:42 pm
10/12/18 6:42 pm
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Originally Posted by gunner
I'm sure I have my original slide rule hidden away in the loft somewhere
I don't think I've actually used logarithm tables since learning how to in high school and I'm pretty sure I'd have to fumble around for a while if forced to multiply two large numbers using them rather than my trusty TI-59 or HP 41CX. Going further off-topic, development of programmable scientific calculators reached a plateau with these two c1980 calculators. By then every key had three functions assigned to it, ROM modules for additional specialty functions, and archival storage on magnetic cards, so there wasn't much more to do to improve them (graphical displays are only a marginal improvement). As a result, and despite the tremendous developments in microelectronics and data storage over the past 40 years, if one of these two c1980 calculators can't do what's required I pretty much need a computer anyway, not a 2018 calculator (nb. I do have newer calculators as well)

Attached Files HP41CXTI59.jpg
Re: 1928 Ariel Model C [Re: Magnetoman] #752474
10/12/18 7:48 pm
10/12/18 7:48 pm
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I won't pretend to know how to do this on a computer.

!!!!!!!!!!!!!!!!!!...................(\ /)
!!!!!!!!!!!!!!!!!!.................(((\ /)))
!!!!!!!!!!!!!!!!!!..............(((((\ /)))))..........I'm trying to show apposing directions
!!!!!!!!!!!!!!!!!!............(((((((\ /))))))).........of travel for the drag area when it twist.
!!!!!!!!!!!!!!!!!!..........(((((((((\/)))))))))........All the periods are just to keep the drawings
!!!!!!!!!!!!!!!!!!...........((((((((/\))))))))..........from collapsing next to each other when posted.
!!!!!!!!!!!!!!!!!!...............(((((/ \))))))
!!!!!!!!!!!!!!!!!!..................(((/ \)))
!!!!!!!!!!!!!!!!!!.....................(/ \)

straight..................twisted drag to side of
drag......................valve/cap, also reduces
........................... forward pull as it turns

I'm just think out loud.

Last edited by franko; 10/12/18 8:03 pm. Reason: trying to learn how to post this stuff
Re: 1928 Ariel Model C [Re: Magnetoman] #752518
10/13/18 12:00 am
10/13/18 12:00 am
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Originally Posted by Magnetoman
Originally Posted by gunner
I'm sure I have my original slide rule hidden away in the loft somewhere
I don't think I've actually used logarithm tables since learning how to in high school and I'm pretty sure I'd have to fumble around for a while if forced to multiply two large numbers using them rather than my trusty TI-59 or HP 41CX. Going further off-topic, development of programmable scientific calculators reached a plateau with these two c1980 calculators. By then every key had three functions assigned to it, ROM modules for additional specialty functions, and archival storage on magnetic cards, so there wasn't much more to do to improve them (graphical displays are only a marginal improvement). As a result, and despite the tremendous developments in microelectronics and data storage over the past 40 years, if one of these two c1980 calculators can't do what's required I pretty much need a computer anyway, not a 2018 calculator (nb. I do have newer calculators as well)


Funny you should mention that
First programmable I bought was a Hp 25, from the unreliable memory it was the cheapest of the line up 25 & 35 and I was banned from using it in exams but the same tutors would pinch it in prac sessions to run the results through as it was a lot quicker than preparing punch cards for the brand new IBM 360 then waiting 2 days for computing services to run them to find there was a syntax error & you have to punch them all again, anyone miss fortran ? The data operator at NSW Public works would borrow the 21 to run all of the surveyors stadia data through because it was quicker than the magnetic card "computer" they had in the office.The district engineer was so impressed he bought one for each division out of his own pocket and the IR printer to go with it, because the Government would not stump up the $$$.
Left Uni firm in the belief that with the 25 I would never need a computer which just goes to show I have been wrong most of my life.
Kept that calculator for near 10 years till I had to make battery packs for it so it got replaced with the HP27 s , a lot cheaper version with only 2 functins per key.
Still got the 27s, used it for 30 years to run 2 different business .

Apparently those old TI & Hp's are now worth big money and have quite a cult following.
The geek in the electronics shop under Vogue went gar gars when I told him he could have my old 25 one day when he asked why I was using so many button batteries.
Never paid for a battery after that .

Last edited by BSA_WM20; 10/13/18 8:33 am. Reason: Failing memory had the wrong model.

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Trevor
Re: 1928 Ariel Model C [Re: Magnetoman] #752542
10/13/18 5:38 am
10/13/18 5:38 am
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Canterbury, New Zealand
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Ha ! Great story Trevor. I recall tripping over and dropping a big bunch of punch cards for a Fortran satellite simulation program, running on a Burroughs B6718 mainframe that was probably the size of my house. The program had taken weeks for me to get almost working - just about cried. Remember having to work your way through those damn hexadecimal crash dumps to work out what had gone wrong ? Programmers don't know how easy that have it these days !!!

I had cause last year to visit the University Physics lab where I did a lot of pracs; they still had the HP rpn calculator with its beady little red digit display mounted on a stand that we all used in 1976 !

Cheers,
Bevan

Last edited by BevanC; 10/13/18 5:45 am.
Re: 1928 Ariel Model C [Re: gunner] #752553
10/13/18 8:20 am
10/13/18 8:20 am
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Scotland
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Originally Posted by gunner
navigation by sextant is now being retaugt by various militaries incase of gps failure, so its always good to have a fallback.

So I'll have a marketable skill when I'm so doddery that actually lifting the sextant will cause fallback ... <sigh> ... cool

Re: 1928 Ariel Model C [Re: BevanC] #752556
10/13/18 8:36 am
10/13/18 8:36 am
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Sydney, Oz
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Sydney, Oz
Originally Posted by BevanC
I recall tripping over and dropping a big bunch of punch cards for a Fortran satellite simulation program, running on a Burroughs B6718 mainframe that was probably the size of my house. The program had taken weeks for me to get almost working - just about cried.
While we reminiscing about vintage computers, that's why we were taught to number the cards (by 10s in case we had to add lines)

Re: 1928 Ariel Model C [Re: BevanC] #752572
10/13/18 10:16 am
10/13/18 10:16 am
Joined: May 2004
Posts: 3,893
Sydney Australia
B
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Joined: May 2004
Posts: 3,893
Sydney Australia
Originally Posted by BevanC
Ha ! Great story Trevor. I recall tripping over and dropping a big bunch of punch cards for a Fortran satellite simulation program, running on a Burroughs B6718 mainframe that was probably the size of my house. The program had taken weeks for me to get almost working - just about cried. Remember having to work your way through those damn hexadecimal crash dumps to work out what had gone wrong ? Programmers don't know how easy that have it these days !!!

I had cause last year to visit the University Physics lab where I did a lot of pracs; they still had the HP rpn calculator with its beady little red digit display mounted on a stand that we all used in 1976 !

Cheers,
Bevan


Gees you Kiwis had it good.
Undergrads had to use optical cards, only honours or post grads had the luxury of punch cards
I have always been a grub ( still am ) but very quickly found the card readers could cope with plain old B pencil marks rather than the requested 2B which used to smudge or transfer from one card to another.
Came across these a few days ago [Linked Image] but I think the cans of hair spray have probably gone off.

And Shane allways thought the requirement to number the cards was to prevent you reusing old cards or borrowing some from a friend that actually worked, cause the tutor alway inspected them and you got an F if they were numbered out of squence.

Last edited by BSA_WM20; 10/13/18 10:26 am.

Bike Beesa
Trevor
Re: 1928 Ariel Model C [Re: RPM] #752623
10/13/18 2:56 pm
10/13/18 2:56 pm
Joined: Nov 2011
Posts: 4,834
U.S.
Magnetoman Online content OP

BritBike Forum member
Magnetoman  Online Content OP

BritBike Forum member

Joined: Nov 2011
Posts: 4,834
U.S.
Originally Posted by RPM
I think 87 lbs on the seat is high for that bike.
Something I meant to write earlier that has nothing to do with the Ariel, but does have to do with valve springs, is a couple of days before the end a Cannonball participant lost one of the pushrods from his i-o-e 1914 Harley somewhere along the route. However, he said it ran nearly as well without it as with and he continued riding the bike without the pushrod until the end.

The fact that his engine still worked means his valve spring was weak enough that the pressure difference on the intake stroke was sufficient to open the valve and suck enough fuel in to keep that cylinder happy. This means that, assuming his inlet valve was ~1.5", the seat pressure was less than ~8 lbs.

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