1971 Oil In Frame Triumph Bonneville Restoration: Tire Choices

The old Bonneville needs new tires and inner tubes so I'm wrapping my head around olde fashioned, pre-metric motor-bike tyre sizes.

Those would be the Dunlop K70s that came with the Bonnieville back in the day.
Fortunately Dunlop is still looking after the bike they designed the tire for.

The '71 Triumph Bonneville came with 3.25 X 19″ front & 4.00 X 18″ rears and used Dunlop K70 tires as standard equipment.

It looks like there are modern Dunlop options for vintage SAE (non-metric) wheels at Revco where I've gotten my last two sets of tires.  The handy chart below shows metric and imperial conversions but after some digging I was able to find SAE/pre-metric modern Dunlop K70s that are the exact fit for the bike.  Using recent versions of original equipment that give me the benefit of modern rubber durability and grip while still keeping close to the originally engineering intent in Triumph's tire choice is fantastic.  I'm not trying to recreate riding in 1971, I'm trying to start with that technology and update where prudent for 21st Century use.

  Tire Charts                               Motorcycle Street Tire Size Conversion Charts

Metric 80/90 90/90 100/90 110/90 120/90 130/90 140/90	Alphanumeric - NA- MH 90 MJ 90   ML 90 MN90/MP90/MR 90 MT 90 MU 90	Inch-(Series90) 2.75 3.00/3.25   3.25 3.50 4.00/4.25 5.0 - NA-	Inch-(Series82) - NA- - NA- 3.60 4.10 4.25/82/4.40 5.10 - NA-	Front Tires: Metric 80/90 90/90 100/90 110/90 120/80 120/90 130/90 Alpha MH90 MJ90 MM90 MN90 - NA- MR90 MT90 Inch 2.50/2.75 2.75/3.00 3.25/3.50 3.75/4.00 4.25/4.50 4.25/4.50 5.00/5.10	Rear Tires: Metric 110/90 120/90 130/80 130/90 140/80 140/90 150/80 150/90 160/80 180/55 200/60 230/50 Alpha MP85 MR90 - NA- MT90 - NA- MU90 MV85 MV85 - NA- - NA- - NA- - NA- Inch 4.50/4.75 4.50/4.75 5.00/5.10 5.00/5.10 5.50/6.00 5.50/6.00 6.00/6.25 6.00/6.25 6.80/7.00 7.00/7.25 7.90/8.00 9.50
Size 120/80V16 130/90H16 130/90V16 500S16 MT90H16 3.00 130/90H16 3.00 140/90H16 140/80VB16 140/90H16 150/80V16 160/80H16 160/80H16 200/60VB16 120/80V18 120/90V18 120/90H16 130/80V18 130/70VB18 150/70VB18 140/70V18 170/60VB18 180/55VB18 230/50 X 15	Rim 2.75 3.00 3.00 3.00 3.00 3.00 3.50 3.50 3.50 3.50 4.00 4.00 5.50 2.75 2.75 2.75 3.00 3.50 4.00 4.00 4.50 5.50 7.00 to 8.00	Overall Width 4.7 5.00 5.2 5.2 5.3 5.4 5.8 5.9 6.0 6.2 6.4 6.8 7.9 4.8 4.8 4.9 5.2 5.4 5.9 6.1 6.9 7.0 9.5	Overall Diameter 23.8 25.4 25.0 26.4 25.3 25.6 25.6 24.8 25.8 25.4 26.1 26.1 25.9 25.9 26.4 26.3 26.3 25.4 26.2 25.7 26.0 26.3 25.3

Note: Measurements are based on the given rim widths. A rough rule of thumb: Each additional 1/2-inch of rim width will be approximately 1/4-inch more in each tire width.

The K70s at Revco are just over a hundred bucks a pop and Counteract Balance Beaded inner tubes are actually cheaper than name brand plain old rubber inner tubes. I've been using the Counteract beads for years to great effect so they'd be my first choice even if they weren't cheaper. All in I'm looking at about $320CAN ($250USD) for new rubber for this vintage restoration project, which considering the price of some of the other parts is pretty reasonable.

In order to rebuild the wheels I'll need to replace the bearings and clean up the brakes before putting new pads and hydraulic brake cylinders back in them. All that and getting the frame sorted out will get me back to a correct rolling chassis ready for the upgraded engine.

Somewhere at the end of all of this will be a road worthy '71 Triumph Bonneville, but it's a lot of parts to find and get in and then a lot time in the garage to get there. I'm hoping it'll be on the road for next year's riding season.  As we thaw out here in Canada I'll be out on the Tiger and GTR and not spannering so much.

Meanwhile, here are some more motorcycle tire sizing reference charts found on the interwebs:

1971 Triumph Bonneville Restoration: Gudgeons, Johnson Rods & Cylinders out! (oh my)

I've got a degree in English, but working on the old Bonneville is stressing out even my vocabulary:

That'd be your gudgeon pin right there.

Gudgeon: one who will bite at any bait or swallow anything, credulous or gullible person Mer. V. I. i. 102.  (that might apply to this project)

Definition of gudgeon

1: PIVOT sense 1, JOURNAL  (we're getting closer)

2: a socket for a rudder pintle (a rudder pintle?)

Definition of gudgeon pin: WRIST PIN

Definition of wrist pin: a stud or pin that forms a journal (as in a crosshead) for a connecting rod (that's it!)

They can make up anything! Nobody knows!  Well, you need a new Johnson Rod in here!

A few people know, George.  Consumer ignorance is expensive, but who has time

to understand the machines they depend on?

Gudgeon pins?  After the massive fight that was removing the seized cylinder head, I was bracing for misery, but I was able to pop the circlips (!) out and tap the gudgeon pins (!) through with no sweating and swearing.  Pink Floyd was playing on the computer and I think music from its era calms the old Bonneville down when I'm working on it.

The circlips popped out easily and a 3/8 inch socket extension was the perfect size to tap out the 'wrist' pins.  I thought the one on the seized side might cause more problems because it had been stuck in place with moisture but it didn't and both came out easily leaving a motor bereft of its pistons.

British Cycle Supply Co. delivered my 750cc kit quickly and without any headaches (and also for about $200 less than comparable kits out of the USA), so I got the shiny new bits out and had a look:

You'd think a 750cc head would look significantly different to the stock 650cc unit, but you have to look closely to see a difference in size.

I had a close look at the connecting rods and they appear to be in good shape and the bottom end of the motor moves freely.  I think next steps are to remove the rest of the engine from the frame, give the oil-in-frame a deep clean and then recoat it with some quality paint.  With the frame cleaned up and sorted I'll strip the rest of the motor and clean everything out to ensure nothing's whacky before I begin the great rebuild.

I could just chuck it all back together now and hope for the best, but if it ends up having other niggles rushing things at this point is just false economy.  I'm not worried about making the bike look mint, but I do want it to be dependable and that wouldn't be the case if I haven't checked it over completely after such a long (30 year?) layoff.  An engine out deep restoration was always the intention here and I'm not in any kind of rush since the other two bikes are both five by five and felt fantastic on their first rides of the year this past weekend.

The gudgeon pin itself looks to be in good shape, which is good because the head kit didn't come with new ones.  The circlips came out nicely too but the kit did come with those.  It amazes me that even specialized material like that in these cylinders can withstand the extreme forces they operate in.  This Bonnie had done at least twenty thousand miles on these cylinders and they're still in remarkable shape considering they were face to face with more than 17 controlled explosions every second (a spark plug typically fires about 17 times per second at 2000rpm!).  You'd think all that heat and violence would cause more wear than I'm seeing in the beating heart of this motor.

This is the 3/8 inch socket extension I used to tap the gudgeon pins out.  Nothing grabbed or slowed the process down and I barely had to apply any pressure.  I might have even been able to push them out had I been so inclined.  I caught the pin as it came loose and the cylinder lifted off the connecting rods easily.  Again, considering the extreme conditions the heart of every engine operates under, I'm impressed by the engineering and metallurgy that makes all this possible.

The new cylinders don't have the carbon build up from all those combustion cycles and look pretty spectacular in their pristine newness:

Here's the whole kit from British Cycle Supply.  It includes the cylinder head, cylinders, piston rings, circlips for the gudgeon pins and a head gasket.  I swiped the last one they had in stock for $688.75CAD ($535USD - told you I got a good deal).  Unfortunately I might be the last person on the planet to get a 750cc kit that cheap.  Prices will be going up on the new stock and probably even higher than that as we're in an inflationary spiral thanks to Putin overreaching and years of pandemic fueled broken supply chains; we live in interesting times.

Another tool came in that's interesting.  I was reading Practical Sportsbikes last week (highly recommended if you love bikes and getting your hands dirty on them), and editor Chris mentioned an endoscope smartphone camera he was using on a project bike to inspect the internal parts of an engine.  I found one on Amazon for under $40CAD and it came in on the weekend.  It lets you see parts of the engine that haven't seen light before.  It's an exciting thing that offers you a look into the secret life of engines.  I'm looking forward to using it as i continue to work on the Bonnie.

Through an inspection hole inside the engine - it's disco in there!

That look on my face after the first ride in a long, long time.

The 12 year old Kawasaki (left) and the 19 year old (!) Tiger (right) were keen to turn a wheel after a long hibernation.

Bison were out bisoning at Black Power Bison Co. when I was out for a ride in balmy 6°C March Sunday.

First Ride of the 2022 Season: Scratching That Itch

Imagine having an itch you can't scratch for 112 days.  Riding a motorcycle in Canada is an ongoing act of stoicism.

It was a long one this Canadian winter.  I'm usually able to get out for a cheeky February ride, but not this year in Ontario. Winter started later but when it came it clamped down on us like an angry professional wrestler and didn't offer any breaks from Polar Vortexes and snow.  My last ride was mid-November, it's now March.

T'was -22°C on Friday and tonight we've got freezing rain and snow into tomorrow, but it was a balmy 6 today so off I went.

The C14 started on the first touch and was bullet proof on a 30km ride up and down the Grand River:

The bisons were out at Black Powder.

It was mennonite o'clock as I shook the cobwebs out of the Connie.

The Tiger took a bit more convincing but that wasn't its fault, I'd had the whole fuel injection system out for a cleaning and it needed to get represussurized.  Once it had fuel it took off like a rocket!

Leaning into a corner, finally!

The zipper replacement on the jacket is working like a charm!

The roads were thick with sand and salt so after a cleanup everyone is back under a blanket waiting for the next break.  I'd be a year rounder if I still lived in Norfolk (UK).

On the upside, the 750cc cylinder head for the 71 Bonnie project came in so I've got other things to do!

On bike photos were taken with a Ricoh Theta camera attached to the windshield and auto-shooting every 8 seconds.  If you're curious, here's a bit on how to make awesome on-bike 360 photos.  Here's another published on Adventure Bike Rider Magazine in the UK:  How to capture 360-degree photos while riding your motorbike.

Looking forward to leaning into more corners in less than another 112 days!

My First Distinguished Gentleman's Ride

I'm going to get past my age related hipster-imposter-syndrome and commit to taking part in the The Distinguished Gentleman's Ride this year, complete with ascot and tweed.  I bet I have a pillion willing to dress up and join me.  I'm hoping I can channel my granddad's riding style when I do it.

From my DGR Suggestion from the summer of 2020.

My '03 Triumph Tiger also struggles with the idea of being a faux-classic hipster style icon (DGR likes classics or faux classics to fit the image - I'd argue the Tiger is a kind of, um, scrambler?).  Tigger's too genuine for that kind of style police nonsense, but it's an old warhorse with over 80k on it from another era so we're both going to commit.  I wouldn't take the C14, that's missing the point, but the Tiger deserves the work.

The Concours is a fine thing and my wife and I are enjoying the rides together, but the old Tiger is still my two-wheeled spirit animal.

The question now is do we fight our way into the misery that is the GTA for an event in the Six with hundreds of riders or enjoy a similarly (time wise) ride through the country to London for a smaller event with far fewer riders but without the traffic?

There are many Canadian DGR events forming this spring to ride on Sunday, May 22nd:  Get out to one if you can, and don't be anxious about not meeting the hipster bike style code (though do dress nicely).

This is last year's poster - I'm sure they'll come up with a 2022 one shortly (it's on Sunday, May 22nd.)

With age comes wisdom, but age often comes alone

I'm up early on a Sunday morning out of a nightmare. It's a recurring one where I'm forced to do nonsensical things at work designed to run me into the ground and make me feel like my presence is meaningless and I don't matter. It's your typical lack-of-control nightmare and I always wake up from it in despair, but relieved that it isn't what's actually happening (at least not that badly).

I'm in that space late in my career when I want to direct rather than act but don't have the network around me that enables me to do that.  As I approach retirement I know more and more people who have crossed over into it.  I also know more people who are getting properly old and are struggling with the complications that brings.  Getting old is difficult and few people seem able to do it with any kind of grace.

Oscar Wilde's famous quote, ""With age comes wisdom, but sometimes age comes alone" comes close, but I'd reword it - I suspect most people aren't any wiser towards the end.  A few years ago we were working away on circuit building in class when one of the grade nines wondered out loud, "why is it that in movies old people always seem so wise and kind, but in real life they just kinda suck?"  This sparked a heated debate where many other students said that their grandparents were lovely, but when I asked them to name any other elderly people who were so giving and wonderful the room got silent.  It seems that only nepotism trumps the worst habits of aging.

As you get older it's difficult to retain a Yoda-like calm and act benevolently for the good of others without making it all about you.  You become less capable and have less of an impact in the world each year, usually while seeing your income decrease as well.  In those circumstances most people grasp for control and interfere with others in order to retain any kind of presence in a world that has passed them by.  I understand the impulse but I hope I'm not consumed by it.  The past few years have asked more of me than I have and I find myself ducking and covering when I used to be all-out in my teaching, but I hope my reflex to enable and empower others remains even as my ability to do it diminishes.

***

Getting old and retiring from riding has come up before in TMD.  A few years ago Jeff and I rescued a BMW from a retired rider which led to For Whom The Bell Tolls.  This guy had ridden the BMW home from a conference fifteen years earlier, parked it in his shed and it then sat there.  He finally sold it on to Jeff when he honestly told himself he was never going to ride again.  I get all Dylan Thomas about that and think I'll be riding to the end no matter what.  Twenty years of deterioration with no time in the wind at the end of life doesn't sound like living at all. 

Another time the Canada Moto-Guide wrote a strange obituary on a rider who crashed at over twice the legal limit on a rural backroad, suggesting that he was a motorcycling martyr rather than reckless rider who caused his own demise.  There is a different kind of abstract fatalism here that has more in common with the stingy pensioner than it does with those rare elders that have found and express wisdom even in their weakness.  Being honest is a big part of growing old or riding well.  Understanding your limitations honestly allows you to be genuine in your being in whatever state it's in.  There is an unfortunate arrogance around motorcycling (and aging) that often prevents us from thinking about either thing rationally and honestly.  If that's all true, then if I ever get to the point where I can't ride effectively I shouldn't.  That guy who sold Jeff the BMW was wiser than I.

I've tried to apply some eastern philosophy to my riding (and aging) on a number of occasions in order to manage the challenges both things create without devolving into dick-swinging nonsense.  Machismo, or just plain old gender-free arrogance, might move you up in the world of management but it doesn't make you a very nice human being.  I think I'd rather age honestly and retain my urge to mentor and support rather than force my way up the ladder in order to gain a fictional sense of control along with accompanying ego.  When it comes to directing, the only person I really want to direct is myself and I want to do it while enabling myself to act as genuinely and with as much fecundity as I'm able.  Perhaps then I can find myself old without finding myself frustrated and angry, hopefully while still riding.

Hasn't happened yet in 2022 and I'm missing the Frostbite.

This is the kind of thing I don't usually carry with me because I'd go out for a ride and ruminate on things until I found my quiet centre again, Zen and the Art of Motorcycle Maintenance style, but I'm in another never-ending Canadian winter with COVID piled on top (and on the verge of WW3), and instead of being in the wind I'm stuck inside.  This is the only year in the past many where I haven't managed a cheeky February ride on a clear day.  Riding and aging are both very difficult things and doing them well is more than many people can manage, for me it's even worse when I can't get out into the wind.

***

Nothing like a bit of poetry to create some perspective:

Do not go gentle into that good night

Dylan Thomas - 1914-1953

Do not go gentle into that good night,

Old age should burn and rave at close of day;

Rage, rage against the dying of the light.

Though wise men at their end know dark is right,

Because their words had forked no lightning they

Do not go gentle into that good night.

Good men, the last wave by, crying how bright

Their frail deeds might have danced in a green bay,

Rage, rage against the dying of the light.

Wild men who caught and sang the sun in flight,

And learn, too late, they grieved it on its way,

Do not go gentle into that good night.

Grave men, near death, who see with blinding sight

Blind eyes could blaze like meteors and be gay,

Rage, rage against the dying of the light.

And you, my father, there on the sad height,

Curse, bless, me now with your fierce tears, I pray.

Do not go gentle into that good night.

Rage, rage against the dying of the light.

Hamlet, Act 3, Scene 1:

To be, or not to be, that is the question:

Whether 'tis nobler in the mind to suffer

The slings and arrows of outrageous fortune,

Or to take arms against a sea of troubles

And by opposing end them. To die—to sleep,

No more; and by a sleep to say we end

The heart-ache and the thousand natural shocks

That flesh is heir to: 'tis a consummation

Devoutly to be wish'd. To die, to sleep;

To sleep, perchance to dream—ay, there's the rub:

For in that sleep of death what dreams may come,

When we have shuffled off this mortal coil,

Must give us pause—there's the respect

That makes calamity of so long life.

For who would bear the whips and scorns of time,

Th'oppressor's wrong, the proud man's contumely,

The pangs of dispriz'd love, the law's delay,

The insolence of office, and the spurns

That patient merit of th'unworthy takes,

When he himself might his quietus make

With a bare bodkin? Who would fardels bear,

To grunt and sweat under a weary life,

But that the dread of something after death,

The undiscovere'd country, from whose bourn

No traveller returns, puzzles the will,

And makes us rather bear those ills we have

Than fly to others that we know not of?

Thus conscience doth make cowards of us all,

And thus the native hue of resolution

Is sicklied o'er with the pale cast of thought,

And enterprises of great pith and moment

With this regard their currents turn awry

And lose the name of action.

Tao Te Ching Chapter 4

Tao is empty (like a bowl). It may be used but its capacity is never exhausted

It is bottomless, perhaps the ancestor of all things.

It blunts its sharpness. It unties its tangles. It softens its light. It becomes one with the dusty world.

Deep and still, it appears to exist forever.

I do not know whose son it is. It seems to have existed before the Lord.

Tao Te Ching Chapter 5

Heaven and Earth are not humane. They regard all things a straw dogs.

The sage is not humane. He regards all people as straw dogs.

How Heaven and Earth are like a bellows. While vacuous, it is never exhausted. When active, it produces even more.

Much talk will of course come to a dead end. It is better to keep to the centre.

Zipper Replacement on a Motorcycle Jacket

Back in 2016 we did a winter family holiday to Las Vegas and then drove down to Phoenix.  While there my son and I rented a bike and rode the Superstition Mountains just east of the city.  Having done some research, I thought I'd try buying a leather bike jacket while down there as US prices tend to be much kinder than Canadian ones.  I ended up with a Bilt black leather bike jacket that I've used on cooler rides since.  It's not high tech protection wise but the leather is thick and the jacket is a solid thing.  It was the last of the 2014 designs and I got it on sale ($159!) as they were wrapping up their Christmas shopping season at the CycleGear shop in Mesa.  Your typical excellent American sales service too.

Since then I've done thousands of miles with the thing and it has always done the job.  It isn't well vented so it tends to do early spring/late fall duties.  This past fall on my last big ride of the year I was wearing it for the 270km ride up to Deerhurst Resort and then it handled a torrential downpour when I rode into Algonquin Park the next day.

It was all good until on the way home I undid the zipper and it came off in my hand when I stopped for a drink before heading back south.  I managed to get the zipper to reconnect so I wasn't flapping all the way back, but a broken zipper meant the jacket couldn't be used anymore, which made me sad.  What followed was a deep dive into zipper technology as I attempted to fix it.

A six year old leather jacket might not be my first choice when getting caught in a downpour, but it did the job!  The hotel room had a lot of drying leather hanging up in it when I got back.

Some online research had me filling my head with new zipper related vocabulary.  The retaining box on the jacket had come off when I pulled the zipper down.  Most of the online advice (which turned out to be right) suggested that you can't fix a broken box, it requires a zipper replacement, but on a thick leather jacket that seemed like a bit much.  Of course, Amazon sells crap that insinuates that you can fix a broken retaining box, so I wasted money buying that and then found that it wouldn't grip and simply didn't work, even after multiple attempts.

Top Tip:  don't waste your time trying to fix an old zipper.  It took some effort, but removing the old zipper and installing another is just some work and isn't impossible.

I finally ended up buying a quality YKK replacement zipper (after learning an awful lot about YKK zippers).  My crafty wife has all the sewing kit so she gave me a seam ripper that made removing the old thread very easy.  If you've got an exacto knife or craft blades and steady hands you could probably remove the thread that way, but the seam ripper does it without damaging the material.  With the old zipper removed and the outer leather separated from the inner liner, the jacket ended up sitting under my work table for a couple of weeks because the thought of pushing a needle through the leather seemed like a bit much, but it's no harder than other mechanical work (makes your hands ache though).

I got some heavy duty coat thread when I purchased the replacement zipper.  This stuff is nylon-rope strong which helped with the sewing, which I did by hand.  The stitching doesn't look like it's done by a machine but it's consistently spaced and didn't cause any pinch points up the zipper.

I came in through the back lining and out through the existing holes in the leather.  By separating the layers I was able to line up the needle with the holes and then it was just a matter of keeping everything straight as I worked my way up the zipper hole by hole.  Alanna suggested I start at the bottom and work up - that was good advice.

Using the existing holes on the thick hide is the trick.  You might be able to do this on a machine but I don't know how you'd do that as the jacket material is thick and you'd need to align the holes the machine is punching with what is currently there.  Doing it by hand is a bit tedious but it works and means you're not punching any new holes in anything.

When I got to the top I tucked the zipper (I couldn't get one the exact length of the old one so got one about half an inch too long) into the collar which had been separated when I removed the zipper thread.  With the top of the zipper tucked into the collar, I sewed everything up using the existing holes in the leather.  Once again, separating the material let me align the needle with each hole one by one.

The final product zips up like new and has no pinching or clumping on the front of the jacket.  Sewing in the other side was easy.  I separated the zipper once one side was in and then  did the other just the same way.  By the time I was wrapping it up I'd gotten quick at it.

Alanna had a thick needle and that strong thread really helped the process.  With a leather jacket the trick is to use the existing holes in the material rather than trying to punch new ones, which in my case meant doing it by hand.  The end result is that my old leather jacket, which now has some nice patina on it, is back in service and ready for the 2022 riding season, should this never ending winter end.

If you lose a zipper on your favourite old motorbike jacket, don't toss it out.  A replacement zipper is less than $15 (CAD) and with thread and other odds and ends you should be able to replace that tired zipper with something that'll let you enjoy your well loved leather jacket for years to come.