1972 Triumph Bonneville Barn Find

mr_lits · Mar 14, 2016

On Friday the new project rolled into the garage. My friend spied this several years ago in an old warehouse in Eagle River and we were just now able to get a hold of it and open it all up. The bike is complete and has not been fired for years... many years. So it was a bit of a crap shoot just to see whats inside. Upon teardown, which we completed this morning, I was pleased to find most of the major components in good shape. The only major surprise was when we pulled the gearbox drain and at least a quart of water emptied out finishing its drain with a nice brown orange slurry. The frame is going off this week to be blasted and powder coated and the barrels rebored (for the second time in its life). I foresee many... many hours of tearing down, picking apart, polishing, refinishing and reassembling in my future... many wonderful hours... me, grease, gas and coffee.

Stearmen · Mar 14, 2016

Nice 72 Bonneville! Sadly, they are much maligned by the purist, but I like them! One thing, ignore all the arm chair experts on the 2LC front Conical brake! If there is a lot of shoe material left, don't replace them, just have a shop familiar with old brakes deglaze the lining. Then get a modern heavy duty Teflon lined brake cable. If you can find them and afford them, some extended brake arms are really great. Be sure to follow the factory manual on setting up the brakes. Then the front brake will almost through you over the handlebars!

mr_lits · Mar 14, 2016

Yeah I have read a fair bit about those brakes and want to do what I can to beef it up. Read a lot about how they are actually a down grade from the previous years but have a good Brit bike guy helping me along the way so I have that in my corner. Thanks for the tips I really appreciate it. Lot of little querks to the 71&72s, not the Bonnys greatest years but as the bike came complete and for a good price I figured it would be worth the tinker time.

Interbak · Mar 17, 2016

A good parts resource is Northen Eagle Cycles, he specializes in OIF Triumphs. http://www.northerneagle.ca

B

emigran · Mar 17, 2016

GREAT ... good luck on the refurb... and Happy Trails ...

mr_lits · Mar 20, 2016

Interbak said:
A good parts resource is Northen Eagle Cycles, he specializes in OIF Triumphs. http://www.northerneagle.ca

B

Thanks for the link. Looks to be a good source of parts.

kyboots · Apr 21, 2016

Had a 66 Triumph similar while in college. When it ran it was great. Good luck on the project.

kaiser · Apr 21, 2016

Me too, mthe statement about it being good when it ran hits it right on the head. My experinence exactly. Turned me off on English bikes really.

kyboots · Apr 21, 2016

kaiser said:
Me too, mthe statement about it being good when it ran hits it right on the head. My experinence exactly. Turned me off on English bikes really.

That's why you wish them "Good Luck".

Stanley Doble · Apr 21, 2016

Greetings from an old Triumph man. I ran them when they were just another late model used motorcycle and found them to be a lot more reliable than people gave them credit for. But, there are certain secrets to making them reliable. For one, buy a manual and maintain it properly. For another, don't put the battery in backwards. No kidding, they were positive ground like most English cars and bikes, and most of the electrical gremlins were from putting the battery in back to front.

I'm not sure if the 72 motor shares its oil with the primary chain case? I prefer the older model where they are separate. In that case fill the primary with automatic transmission fluid instead of motor oil. Your clutch and chain will thank you, and the clutch won't stick together if you leave it for a week. But if it does stick pull in the clutch and kick the starter over until it frees off.

Other things I remember, you must have the original type rubber mounts for the gas tank or it will crack. If you notice a sudden increase in vibration check your motor mount bolts, they may be loose especially the head steady. If you need a zener diode they are a standard part, from the local electronics shop they used to be $4.50 vs $22 from the Triumph dealer.

So, good luck with your project and I hope you have a lot of nice trouble free rides.

Stearmen · Apr 22, 2016

Stanley Doble said:
Greetings from an old Triumph man. I ran them when they were just another late model used motorcycle and found them to be a lot more reliable than people gave them credit for. But, there are certain secrets to making them reliable. For one, buy a manual and maintain it properly. For another, don't put the battery in backwards. No kidding, they were positive ground like most English cars and bikes, and most of the electrical gremlins were from putting the battery in back to front.

I'm not sure if the 72 motor shares its oil with the primary chain case? I prefer the older model where they are separate. In that case fill the primary with automatic transmission fluid instead of motor oil. Your clutch and chain will thank you, and the clutch won't stick together if you leave it for a week. But if it does stick pull in the clutch and kick the starter over until it frees off.

Other things I remember, you must have the original type rubber mounts for the gas tank or it will crack. If you notice a sudden increase in vibration check your motor mount bolts, they may be loose especially the head steady. If you need a zener diode they are a standard part, from the local electronics shop they used to be $4.50 vs $22 from the Triumph dealer.

So, good luck with your project and I hope you have a lot of nice trouble free rides.

All good advice. The primary gets it's oil from the crank baring, they simply did away with the seal, then it returns to the sump via three small holes in the primary case. Not the best system, belt drives do away with this! Do away with the rectifier and Zener diode, replace them with a Tympanium solid state rectifier, and an electronic ignition. If you can afford them, get a set of new made Amal MK1 carburetors. With these mods you should then have a motorcycle you can actually do 500 mile weekends on, I have!

Stanley Doble · Apr 22, 2016

Could you put a seal on the crank and plug the holes? The separate primary is better. I don't know why they changed it.

I gather you are an 'old hand' and know your way around the Triumph. Good to know you will treat it right.

Stearmen · Apr 23, 2016

Stanley Doble said:
Could you put a seal on the crank and plug the holes? The separate primary is better. I don't know why they changed it.

I gather you are an 'old hand' and know your way around the Triumph. Good to know you will treat it right.

On some of the belt drive conversions they do just what you said. On a funny note, you just drill out the three holes and tap them, put in small screws. If you don't want to strip the engine, you use a lot of grease on the drill bit and tap. I never did that, but I have been told it does keep the metal bits to a minimum!

mr_lits · Jul 24, 2016

After months of wrenching, waiting for parts, and the consumption of unfathomable amounts of coffee and cigarettes, she lives again. The Bonnie breathed life for the first time in over 30 years. She still needs a bit of timing and jetting love before I take her to the streets but she is loud and mean.

The work ended up a total teardown and rebuild. Frame freshly powder coated and and engine blasted, rebored and rebuilt. I am leaving the tank and fender repaints for winter months just want to lay the base down for a good operator. Fresh Amal carbs really helped out and accounted for a third of the total parts cost but are much easier that rebuilding the old ones. Points system replaced and updated with electric Pazon. And of course fresh rubber everything.

A few more days of tinkering (and hopefully some good weather) and I will do some street trials. Keep ya'll updated.

Stearmen · Jul 25, 2016

Looks great even with the old paint!

Edward · Jul 27, 2016

Lovely bike. Triumph never lost their aesthetic.

RJR · Jul 27, 2016

Edward said:
Lovely bike. Triumph never lost their aesthetic.

+1

mr_lits · Jul 27, 2016

Thanks gents, I am taking out tonight for street trials. Needed a bit of timing adjustment and as soon as I had that all cleared up it started raining. But today it is dry and temps are good enough to take it for a spin. Hopefully I will get some video and more photos tonight.

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