Bringing My '79 Bonneville Special Back to Life

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Sep 3, 2007
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As I noted in another thread http://accessnorton.com/norton_commando2084.html I have a '79 Bonneville Special that I pulled out of storage yesterday and am working to make it run again after almost twenty years. I'm faced with the following challenge:

I have a European tank which holds more fuel and would like to replace the American "peanut style" tank currently fitted to the Bonny.

Here's what the workshop manual says on page E3:

REMOVING AND REPLACING THE FUEL TANK

..."Remove the rubber grommet from the centre of the fuel tank and unscrew the sleeve nut revealed below."

"The tank can now be pulled away from the frame. Note assembly of rubber sleeve and washers securing the tank. See Fig. E2.

Figure E2 is quite clear and shows a special bolt with a round head. That head fits into a slotted receiver welded to the top of the frame, diagrammed clearly on the opposite page (E2).

The sleeve nut will not turn; the entire special bolt turns. Oil on the sleeve nut didn't help.

I tried lifting the tank to put pressure on the slotted receiver on the frame, hoping it would hold the bolt enough to allow the sleeve nut to turn. No such luck.

Reaching under the tank, I was able to remove a semi-circular rubber fitting which cushions the tank. I installed an old guitar D-string under the tank so I could put pressure on the bolt in a further attempt to hold it fast. Although the bolt/sleeve nut assembly was harder to turn, it did continue to turn.

I just (this moment) had another idea. I'm going to use a larger (perhaps an E) guitar string, loop it around the bolt and use a lever in hopes that by completely encircling the bolt I can exert enough pressure to hold it tightly enough that the bolt won't turn while I loosen the sleeve nut. I'll post the results afterward.

Has anyone else had this problem? Is there a known way to loosen the sleeve nut? I'd appreciate any tips that might reside within y'all's experience.

Al
 
Re: Bonneville Tank Removal

Tulsaalva said:
Is there a known way to loosen the sleeve nut? I'd appreciate any tips that might reside within y'all's experience.

Try sliding the tank as far backwards as you can, and hold it there while you try to unscrew the nut, as the bolt could be a normal hexagon head type? The one in the manual diagram seems to show it to be similar to a coach bolt? I don't know if that is what you would call them in the US (a shallow dome head with a squared piece below (or in this case above) it which should probably sit in the groove to stop it turning)? If it is a hex head (as my own is) one of the corners of the bolt hexagon should then catch in the frame slot that holds the bolt and that is likely to give some resistance to stop it turning?
 
I bought this Bonny new and resold it to a friend in Germany. Eventually, after I'd returned to the States, he shipped the bike to me more or less because he owed me some money. That's not exactly right as I'd never have asked him to do that nor tried to collect the money. He's like a brother.

I'm telling y'all that because I want to disclaim any responsibility for what I found tonight. I've never removed and refitted the tank before. My guess is that the artist who did the mural on the tank is responsible.

Your tip almost worked, L.A.B., and definitely led to the successful removal of the tank. When pushing the tank to the rear didn't hold the bolt tight enough to loosen the nut, Fifteen and I tried pushing it forward. The bolt slid easily out of the slot on the frame and the tank lifted off. After that it was easy to clamp the round head of the bolt in a pair of vice grips and remove the very tight! nut.

The problem was that a nut of the wrong thread pitch (wider) was used and was a regular nut, not a sleeve nut. Consequently, the threads on the end of the bolt are quite distorted. I'll try to find the correct replacement but can probably rethread this one if need be. I'll need to find the proper nut, of course.

I've measured and know the thread is not metric. I vaguely remember a conversation years ago with Peter Britain in which he told me the Meridan Triumphs used American-sized fasteners. Do you know if this is true? Whitworth went by the wayside long ago, didn't it?

You're right. The bolt has a round head with a "flat" machined into it to fit into the slot. It is held in place with a flat washer and a spring washer retainer which grips the shoulder of the bolt, keeping the flat in the slot.

L.A.B., you are truly a gentleman and a scholar! Your range of knowledge is amazing and your willingness to take time to help, extraordinary. Without your suggestion, I'd still be scratching my head in wonder. Thank you!

Cheers,
Al
 
Tulsaalva said:
I've measured and know the thread is not metric. I vaguely remember a conversation years ago with Peter Britain in which he told me the Meridan Triumphs used American-sized fasteners. Do you know if this is true? Whitworth went by the wayside long ago, didn't it?

I'm glad that what I said was at least of some help, (as I'm a bit of a newbie to Bonneville ownership myself) and you are correct about the fasteners being American thread, Triumph/BSA did the main change over in 1968 so the majority of fasteners were American Unified thread (UNF UNC UNEF as we in the UK know them) from then on, although they did continue to use the odd British Standard thread here and there.

Amal carbs & fuel line fittings do not have Unified threads.

Nortons however, continued with BS threads BSW/BSF/BA/CEI/ -and more until 1972 when there were some changes to American Unified threads (at a time when the rest of the UK auto industry was converting from Unified to metric!) so Commando thread identification can be a bit of a headache; -especially as they still used BSW hexagon sizes for some of the Unified fasteners!
 
The Bonny keeps getting cleaner! The hardward store had the proper nut and matching die. I was able to clean up the threads on the bolt so as to make it usable. As y'all can see below, the European Tank is on the bike. I also put the side covers on, but the reds don't seem to match, so I think tomorrow I'll put the black Bonneville Special side covers back on.

I also need to go up north to Jack's Motorcycles and get a new battery. I'll try to get that done tomorrow, too. I can't wait to kick it over! :)

Bringing My '79 Bonneville Special Back to Life


I have two of the logos that plug the hole in the tank that allows access to the bolt that holds the tank on. I never noticed before, but the Triumph logo on one is silver and the other is gold. Both paint schemes have gold striping in the trim so I don't know which one came originally with which tanki. Since both tanks have the same chrome gas cap, I chose silver. It surely doesn't matter but it interests me because, to me, the history of the machine is an important part of bringing the Bonny back to life.

Bringing My '79 Bonneville Special Back to Life


Another interesting thing I discovered in changing the tanks is that there are two small threaded holes (one on each side) in the forward part of the tanks but there is nothing there to bolt to them. Does anyone know what they are for?

If I hadn't discovered this website, both my ol' Brits would probably still be sitting in the store room with squirrels homesteading the Norton's battery box. I owe y'all another vote of thanks!

Al
 
Tulsaalva said:
Another interesting thing I discovered in changing the tanks is that there are two small threaded holes (one on each side) in the forward part of the tanks but there is nothing there to bolt to them. Does anyone know what they are for?

Presumably you mean holes on the *underside* of both the tanks?

Those holes are likely to be the tank brace bolt holes? As there would normally be a brace between the two sides of the tank, these are secured on the later models by bolts (earlier tanks have studs/nuts).

This brace is important, as it stops the tank flexing due to vibration, which can cause the tank to eventually split!

US and UK/gen. export tanks should have them, although the part numbers change for the different tank types.

If you do not have one, then I suggest that you either get one, or make one (or two if you intend to use the other tank at all?) as they are only simple flat steel strips.
 
Yes, L.A.B. They are on the underside of the tank — one on each side, near the front. I'm sure they're the ones you're talking about.

No, I don't think I have such a bracket, although I'll sift through the spares I do have to make sure. I just went down to the garage and looked at the bike but was unable to see where brackets would bolt to the frame. The holes in the tank are obvious, but where does the other end fit? Will I have to remove the tank to install them?

Oh!! I think I get it! Is there just a simple steel bar that reaches from one side of the tank to the other, not being connected to the frame at all? If that's the case, it should be very easy to both make one and to install it, nicht wahr?

I don't plan to use the "peanut" tank. Firstly, I'm not a fan of air-brushed motorcycle tank murals (my friend had that done), secondly, the European tank has a greater capacity and, thirdly, the Euro tank looks better, in my opinion.

Again, thanks for the help!

Al
 
Tulsaalva said:
I just went down to the garage and looked at the bike but was unable to see where brackets would bolt to the frame. The holes in the tank are obvious, but where does the other end fit? Will I have to remove the tank to install them?


No, the brace does not connect to the frame.

It just connects both sides of the tank together to stop it flexing.

When fitted, the brace passes under the frame tube.

The tank needs to be fitted in position first, then the brace is bolted in position afterwards.
-------------------------------------------------------
See workshop manual section E1:


"REMOVING AND REPLACING THE FUEL TANK

Unscrew the two bolts which retain the tie strap at the forward end of the tank. Note the positioning of the spacing washers.

The tank can now be pulled away from the frame....."
etc...
 
My service manual, published in 1978 by Triumph Motorcycles (Meridan) Ltd., does not include the sentence "Unscrew the two bolts which retain the tie strap at the forward end of the tank. Note the positioning of the spacing washers." It also does not show the positioning of the spacing washers.

The only drawing in section E1 (page E3) is Fig. E2, that of the "Fuel tank mounting." There is a full-page drawing on page E2, showing "Fig. E1. General arrangement of frame assembly." but the strap of which you speak is not shown.

Nevertheless, I believe it would be a good idea to make a strap and install it. I would be most grateful, L.A.B., if you might inform me how to install the spacing washers. It would be perfect if you could scan section E1 in your book and either email it to me or post it here. Then I could print it and add it to my manual.

Again, thanks so much for your help. I fear it will not be the last time I ask.

Al
 
Tulsaalva said:
My service manual, published in 1978 by Triumph Motorcycles (Meridan) Ltd., does not include the sentence "Unscrew the two bolts which retain the tie strap at the forward end of the tank. Note the positioning of the spacing washers." It also does not show the positioning of the spacing washers.

Yes you're right, that information does not appear to be in section E1 in the earlier factory manual versions! All Bonneville/TR7 tanks would seem to have had the bolt-on tie strap from 1974.
The T140 manual was originally written in 1973 and updated as necessary, but the need to add this extra information about the tie strap appears to have been overlooked until much later on?

My own Bonneville tank which I believe to be from a 71/72 model (the bike is a '78 model) has studs (actually welded-on bolts), however, the strap & fittings do not appear to be listed for those years, so it may well be a modification done by a previous owner, or a factory upgraded part supplied at a later date? So the remark I made earlier about 'early' T140 tanks having *studs* may be wrong?

Tulsaalva said:
The only drawing in section E1 (page E3) is Fig. E2, that of the "Fuel tank mounting." There is a full-page drawing on page E2, showing "Fig. E1. General arrangement of frame assembly." but the strap of which you speak is not shown.

The tie strap isn't really a part of the 'frame assembly' so would explain why it isn't shown in Fig. E1? And it isn't illustrated in the later (more specific to '79 E-onward models) manual either, it's just mentioned in the text as I quoted it.



Tulsaalva said:
Nevertheless, I believe it would be a good idea to make a strap and install it. I would be most grateful, L.A.B., if you might inform me how to install the spacing washers.

By saying: "Note the positioning of the spacing washers" I think they were just referring to the general assembly of all tank fittings (including the sleeve nut assembly)? As the parts diagrams ('74-on) shows the following tie strap parts in the following fitting order = strap (83-4395 x1 US tank/83-4118 x1 UK/Gen. export tank)-washer (60-2321 x2)-spring washer (60-2428 x2)-bolt(14-0113 x2) -so that's it, just a washer, spring washer and bolt each side to hold the strap.


Tulsaalva said:
It would be perfect if you could scan section E1 in your book and either email it to me or post it here. Then I could print it and add it to my manual.

OK - I will contact you by e-mail.
 
Sorry, L.A.B. The sentence "note positioning of the spacing washers" led me to believe there was a diagram. There is a space in my manual where it might have been so I thought I might be able to add the (non-existant) diagram to my book.

I'll just write the information about the tank strap on the same page.

My guess is the strap disappeared as one of Meridan's many attempts at survival. If one were to drop a part that cost a pound, it might save 100,000 pounds over the long haul.

In any case, I'll make a strap and write about it in my manual. Thanks again for your help!

Al
 
Tulsaalva said:
My guess is the strap disappeared as one of Meridan's many attempts at survival. If one were to drop a part that cost a pound, it might save 100,000 pounds over the long haul.

No, I don't really think so, the strap certainly has a purpose, as it helps to stop the tanks from fracturing!

The strap continues to show up in the parts lists,-right to the end of Meriden Triumph Bonneville production-and beyond, (even the Harris manufactured Bonnevilles appear to have it as it is still included in the Harris parts book).

I would think that these straps generally get discarded by owners, as they may consider it to be a nuisance to remove and refit it each time, when removing/refitting the tank, and owners may not be aware of its actual purpose?
--------------------------------------------------
I am unable to reply to you directly by e-mail, as you have that facility disabled (and I can't send files by PM).
 
Right you are! My email was disabled. I've fixed it in my profile.

I had guessed that the tanks came from the factory without straps because the bolt-holes still contain paint. I don't know if my friend ever fitted the European tank, though.

Here's another question:

I know the American Special came with the peanut tank which was painted black with a gold striping design. That's how it was when I sold it to my friend and bought an R100RS. How was the European Special painted? The Euro tank I have, as you can see from the pics, has a center side panel painted red. I'm thinking it would look better all black and may so-paint the red portion. I've fitted the black Special side-covers because the reds don't match. Both side covers have "Bonneville" on them. The red ones also have "750" while the black ones have "Special."

I know it's all a matter of taste but I'd like the bike to look as original as possible and I doubt Triumph delivered bikes with a red panel on the tank and black side-covers. :)

Fifteen and I spent a couple of hours polishing aluminum and chrome with Never Dull yesterday. The bike keeps looking nicer and nicer!

Al
 
Tulsaalva said:
I had guessed that the tanks came from the factory without straps because the bolt-holes still contain paint. I don't know if my friend ever fitted the European tank, though.

Maybe the underside of the tank has been repainted? Or it was supplied as a spare and never got fitted with the strap when/if it was used? I would be a little bit surprised if it left the factory fitted to a bike without a strap, but who knows?



Tulsaalva said:
I know the American Special came with the peanut tank which was painted black with a gold striping design. That's how it was when I sold it to my friend and bought an R100RS. How was the European Special painted?

They mostly had the US tank, (although there's a photo in Steve Wilson's Bonneville book of the of a D model with the UK/Gen. export tank) , as the Bonneville Special (T140D) was a US style model, and these were all black with the gold pinstripe, and some UK D's had the twin exhaust system instead of the rather restrictive two into one system normally fitted on the D model, apparently.
The UK tank you have is painted in one of the normal E model styles of that period (black with a red panel) , and the matching side covers to that would have been all black.
 
Can you tell me about how thick and how wide the strap needs to be, L.A.B.? My brother works in the aircraft industry and can nick a couple of pieces of stainless steel straps from the scrap bin without incensing his boss.

There is also some one-inch extruded-aluminum alloy "C channel" available along with aircraft-quality bolts and washers (for which I must pay).

Which would you use?

Al
 
Tulsaalva said:
Can you tell me about how thick and how wide the strap needs to be, L.A.B.?

I don't have an original tie strap handy, but I would guess around 3/4" wide by 3/16" thick would be fine for steel or stainless steel? Maybe a little thicker for aluminium but I don't think it's that critical although it may be more likely to fracture than a steel one?
I expect alloy C channel would work OK?
I'd probably go for the stainless option myself, in fact I may very well end up doing just that, as the strap that came with the tank that I have is just a piece of rough steel.
 
Bringing My '79 Bonneville Special Back to Life


I thought I'd show y'all a picture of the ol' Bonny as it progresses on it's way to breathing fire again.

As y'all can see, I've painted the red panels on the UK tank black and fitted it.

I removed the wide American bars and replaced them with BMW R90S bars. They actually aren't BMW bars. A friend made them for me. He used his jig for the BMW "S" type bars but made them with 7/8" tubing instead of 22mm. They fit perfectly after a lot of adjusting of the master cylinder so it would sit upright.

The seating position is perfect! Exactly what I was looking for. Now I'd like to find a fairing much like the old R90S or something like Paul Dunstall used to make. Any suggestions, y'all?

I'm really beginning to like the Special and looking forward to putting some miles (actually, kilometers... the speedometer is still the one that was on the bike in Germany) on it! I can see, though, that I'm going to have to beat Fifteen (He'll be sixteen on Saturday and legal for over-250cc motorcycles.) to the keys. :) Should I require that he spend an hour polishing for every hour he rides?

I owe a huge "THANK YOU!!!" to this website. Otherwise the bike would still be gathering dust in the storage building.

Next comes the Long Range. The squirrel-chewed wiring will make it a more difficult project, I fear.

Al
 
Tulsaalva said:
I'm really beginning to like the Special and looking forward to putting some miles (actually, kilometers... the speedometer is still the one that was on the bike in Germany) on it!

That's good Al. It all seems to be coming along quite nicely.


Tulsaalva said:
I can see, though, that I'm going to have to beat Fifteen (He'll be sixteen on Saturday and legal for over-250cc motorcycles.) to the keys. Should I require that he spend an hour polishing for every hour he rides?

Over 250cc!

He'd only just be old enough to ride a restricted 50cc (moped) on the road displaying 'L' (learner) plates until qualified, in the UK at sixteen after completing a CBT (compulsory basic training) course! And then only allowed a restricted 125cc at seventeen.
If he passed the A2 motorcycle test then he would be restricted to a 33 BHP bike for two years, so he wouldn't (legally) be able to ride the Bonneville until he was at least NINETEEN!
I would tell him how lucky he is that he doesn't have to abide by the UK (I think Europe [EC] is much the same) regulations, -and that's got to be worth at least two hours polishing! http://www.apexmotorcycletraining.co.uk/licences.html


PS
I'm curious to know if you received the files (manual & parts book) that I emailed to you?
 
I did receive the emails with the files attached, L.A.B., but haven't been able to download them. It gets about half-way through when the prompt "Timed Out" appears. I don't know if it my Macintosh or if the files are too large.

I appreciate your efforts. I am able to get by with the Factory manual and a Clymers. I'd appreciate your mailing address, if you don't mind. I'd like to send you a little "thanks" gift.

Al
 
Fifteen (his name on this board will change to Sixteen on Saturday.) took the Motorcycle Safety Foundation's Beginning Rider Course shortly after he turned fourteen. The completion certificate, along with a successful written test, licensed him to ride a 250cc (or less) motorcycle with some restrictions.

Under Oklahoma law, a fourteen year old rider:

1. Must wear a helmet.
2. Can only ride between 3:30AM and 9:00PM. (The early hour is to allow kids to have a newspaper delivery route.
3.. May not carry a passenger, and,
4. For the first thirty days must have a motorcycle-licensed driver with him, either on another bike or in a car. After that he is able to ride on his own.

Since I'm a former MSF instructor, I worked with him after he passed the MSF course, in our neighborhood, fine tuning his control of the bike as well as evasive maneuvers, traffic safety, good braking techniques, etc. I must say I'm pleased with his progress and his maturity in riding.

At age 15.5, a teen in Oklahoma can get a limited learner's permit for a car. He must pass the written test and have a licensed driver, over 21, in the front passenger's seat. At the time he had the auto learner's permit added to his license, the DMV left the motorcycle endorsement intact but failed to include the 14 year old restrictions. He never took advantage of the mistake, though.

We started him in the family mini-van with automatic transmission, went to his older brother's '87 944 automatic, and then my 928S five speed to teach him to shift gears. Fifteen's car, an '82 924 five-speed, a project car I've owned on for years, is almost ready. It has new brakes, braided stainless steel lines, Pirellis, "silber-blau" paint, interior, tinted windows and body rubber throughout. I also have a '78 924 automatic that is finished except for paint, which I hope to do this week if the weather cooperates. Our agreement is that he must drive the '78 auto until it is sold. Then he will get the '82.

I don't know how we would deal with high school if sixteen-year-olds couldn't drive. Our sons, during football season, have to be at marching band practice at 6:50AM daily. They have a practice on Tuesday afternoons, Thursday evenings and a football game every Friday. Band practice begins in July and runs through November if the football team makes the State Championship playoffs, which they always do. This year we won the State Championship. When one includes trips to private music lessons, Jazz Band practice, Rock Band practice, the music store for guitar strings and reeds for their wind instruments, Latin Club, and German Club meetings, chauffeuring them around would be a real hassle!

Al
 
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