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Hi all,
My 69 Bonnie needs the mains bearings replaced and I am not sure whether this is something that I should attempt (with the workshop manual) or whether this is something that is best done by a qualified mechanic. I have searched through the forum and haven't found anything specific on this. I have a 'basic' mechanical background and service my own vehicle and my dirt bike, but the Bonnie is another level.
Thanks in advance for any tips, etc that you all may be able to provide.
 

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croc, it can be done, but you will need a clean shed/garage and a good selection of tools [sockets, spanners, screwdrivers, tension wrench, hammer, neoprene hammer, timing light, Loctite, assembly lube, degreaser, oils, grease, etc etc. The first one is never cheap or easy, but the ones after that are much easier.
If you are in a town that has another Triumph [or pretty much any older british bike] enthusiast in it then knock on their door and introduce yourself...see if they want to be a coach, it would be unusual if they said no, most are only too happy to help....it is pretty much how we all started.
Also a Triumph workshop manual is the bible, a Haynes manual sometimes helps [adds a different perspective] but they do have some mistakes etc.
A mate of mine remotely [he was 400 miles from me] built a 650 Tiger with both manuals and the phone with a few numbers in it...........and he had never done one before and he did a very good job of it. So it can be done.
The added expense is the tools [generic and Triumph special] and gearing up with gaskets, seals, lubes, etc etc. And once you pull the motor apart there are generally other issues like valves, tappets, clutch or primary that you also find...so be prepared for a bit of a journey. But its always the journey that is the best part.


This very forum is an invaluable tool...there are many on here who have a wealth of knowledge and experience...and who can articulate it better than me [we all take a lot for granted at times and miss the little things], so start a build thread and ask as you go. Have a look at Rod Rockets thread: http://www.triumphrat.net/classic-v...140-general-engine-disassembly-questions.html
that's what he did.


Also check out http://www.britbike.com/forums/ubbthreads.php/forums/4/1/triumph-bulletin-board
they have a lot more 650 content.
 

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I have years of experience working on motorcycles and I would say no way a less than highly skilled mechanic is gonna be successful at main bearing job on an old Triumph. Good luck if you go for it!!!
 

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Discussion Starter #5
Thanks for the replies guys.

tridentt150v, you have instilled a little more confidence in me. I already have the tools, oils, etc.

tr4mikek, you have me worried. What is it particularly that may pose an issue?
 

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I can't see the issue...remove crank, get machinist shop to check/measure up and re grind or linish if needed [along with barrels, cams, and followers, then you're good to reassemble.
 

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Hi creativecroc, I just went through '69 Bonnie motor to the very last part including main & transmission bearings. Even tach drive came apart. Only thing didn't take apart was AAU. Did that a few years ago.

It is a large job. Have you done any motor overhaul work, like replacing crank & pistons in a car?

You will need most of the tools in the shop manual. With out tools you risk much damage. A skilled mechanic may jury rig some tools, but make or buy most. You need clutch puller, cam gear puller/installer, crank pinion puller, trans needle bearing tool, puller for crank sprocket. Torque wrench for larger bolts, Torque wrench for smaller bolts. Both US & BS/whitworth wrenches & sockets. The '69 is a mix. You'll need to grind drag link socket to remove sludge trap plug. I recommend make sludge tube puller. You'll need tappet block driver. AAU puller. Engine stand is well worth the money. Make any tools you can to save money if you have time. Engine stand is easy to make. You'll need 6" Vernier calipers & 1" micrometer You do know all the Philips screws are actually Pozidrive & you must use Pozidrive screw driver, not Philips? Need clutch locking tools & chain whip too. Giant socket or tool for trans sprocket nut. I'm sure I didn't list all the tools you'll need.

Trust me, when taking motor out remove at least head & clutch first. Also remove studs at left bottom frame as shop manual states. Makes it much easier. Lifting handles are a real help. The motor is 130# but not easy to grip.

With all the proper tools taking motor apart is not very hard. Crank pinion puller often will need to be ground for clearance. Just how it is, they usually don't fit from factory. If you have a grinder you'll use it.

Once crank is out the bearings are not very hard to change. Often the left bearing is not very tight & can be pried off crank. If tight you'll need a clam shell puller or the like to prevent damage.


The bearings in case are the hardest part. You need to heat case very hot, like 350f & often the bearing will just fall out when turning case over & dropping case on a block of wood. While still hot the new bearing will drop in, but you must line it up with you fingers perfectly. Have a drift & hammer handy just incase it doesn't go all the way down. With wife not home heat case in oven. Both sides you do the same even though right side is ball bearing.

Trans bearings do the same. Heat the case hot. You can use propane torch also. Some heat guns will work too. Don't even think about not heating cases. They must be good & hot.

Trans needle bearings must be installed just right depth. You must make or buy drift. Some have stop shoulder some not. Sometimes the shoulder still doesn't position bearing correctly & you have to adjust depth. Not hard, but you pay close attention.

Take hundreds of photos as you go. Just photo everything even if you don't think you'll need it. Inspect & measure every last part as you remove it. Keep a detailed journal. Have dozens of food storage bags & cardboard boxes. Put parts in bags & write with felt pin what parts are. The amount of parts is staggering. Takes lots of space for all the parts.

Inspect every last part as you remove it. Any parts that need replacing write it in a list. List every single last part, seal, gasket whatever you need. Don't just say motor gasket kit. List everything. Photo bad parts.

You must have a real paper copy of shop manual & parts book. Make notes in both as needed. The '69 parts book uses the old E prefix number system. Go online & find # conversion chart so you can convert to later number system as most sellers use later system. Not hard to figure out, just takes time.

Do not rush. Take your time. As a rookie you can expect to spend several hundred hours by time it's running & tuned. It is process of learning & doing. That takes much time.

Is there a bike club or skilled mentor in your area you can call if when you get stuck with a question? Online is very different that real life. Is there a shop in your area you can travel too for advice & machine shop work you can't do yourself? Many shops that sell parts will give lots of free advice. They will inspect parts for you too.

Suppose you get started then decide it's too much to handle. Is there a shop you can take the bits to & have them take over? Trust me if parts are bagged & marked they won't mind. I've taken over on many jobs the owner decided to pay to have finished. I just hated it when parts were missing. Otherwise no problem.

For machine shop work, ask around for a known good shop. Even if you have to drive 400 miles, it's worth it. Good work results in good results.

Warm the alternator wires with heat gun & don't bend wires more than needed. They will be stiff & fragile. Make sure you store rotor in stator so it doesn't loose magnetism.

A very fun & rewarding job to overhaul these motors. What if you started by taking head & clutch off. If clutch hub is still good, replace the rubbers as they will most likely be worn. That will get your feet wet on fighting these things. If that goes ok, pull cyl. Remove tappet blocks for resealing. That will be a good start.

You get started & email me photos of your progress & I can help. I have photos of the entire process. I can advise you as much as possible via email if you need it.
Don
 

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I have years of experience working on motorcycles and I would say no way a less than highly skilled mechanic is gonna be successful at main bearing job on an old Triumph. Good luck if you go for it!!!
I'm sorry, I cant agree with you here !
Personally, I believe you have to have a certain aptitude and if you don't, then your opinion is valid.

If, as mentioned above by others and from the fact you have had some mechanical experience in the past, be it servicing other bikes or vehicles, then although it will be a whole new experience, but in my opinion, one worth having a go at. I would say there's more old bonnies been rebuilt by enthusiastic owners than skilled mechanics by a long way.
I'm currently doing mine and within a month will commence with the re assembly, I'm certainly no skilled mechanic and its my first motor. But, listen, its not rocket science ! even for the un initiated, you can rebuild.
Here is a great place to start a rebuild thread and you will get questions answered as you go along.
It's already been said, but the special tools and some improvised ones are necessary and of course attention to detail, might sound a bit daunting at first, but once you get into it, with help on the way, its not so daunting.
There is a whole pile of info on line including strip down and rebuild youtube video's there for watching and alot of info on here as well.
So as I first said, if you have the aptitude, want to give it a go and it not be a race, don't be told its only for the skilled mechanic, give it a go, the satisfaction achieved is certainly worth the effort.

Regards
Col
 
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Not really a difficult engine to work on. First rebuild i did was with no information apart from a Haynes manual and a basic spanner set. Later on in life, it became easier as i had some better tools and the Triumph special tools that are needed. As mentioned, you need some ability and knowledge and a feel for just how much tension you can put on bolts in alloy. With these forums, it has become much easier to build an engine.
Just make sure that as you dismantle,put assemblies in separate boxes and where possible, link some with cable ties so you can see you have all the parts for that assembly.
The whole job, if you are new to these engines might take 70 hours to a stage where you are riding it. I take about 40 hours to do the whole job having stripped the engine to this degree 4 times so far. I can take it apart without going through books now. A parts book will be a great help to get assemblies in order without having a few parts left over.
Worth having a go as many so-called mechanics are not experienced with this engine, and ,will not have the special tools.
Get started and enjoy the frustration and then the pleasure of having repaired it yourself.
 

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- Its not a big job --- its lots of small ones ! -- you will definately need special tools - the cost of those tools will be miniscule compared to paying a "specialist" to do the work - if you service your own vehicles then you can strip and rebuild these engines - you will have questions but thats what this site is about
 

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Some special tools and just a few tool cabinets. A lift might become useful and i would not consider working on a bike without one now. I was going to take a picture of the pinion remover but the garage pixies are hiding it today.
I suppose i have been playing with the T120 twin for near 40 years now so i do have a tool for every job on this bike. First time, i just had open end spanners and one socket set and made do and struggled. Often, the special tool will save you money and time. Some parts are easily broken by improvising a tool.

The electric motor on the lift is used to pull the bike up the ramp when my knees are too bad to push it up.I can sit on the bike and remote control the motor which auto stops when the bike is in the right position.
 

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Hi all,
My 69 Bonnie needs the mains bearings replaced and I am not sure whether this is something that I should attempt (with the workshop manual) or whether this is something that is best done by a qualified mechanic. I have searched through the forum and haven't found anything specific on this. I have a 'basic' mechanical background and service my own vehicle and my dirt bike, but the Bonnie is another level.
Thanks in advance for any tips, etc that you all may be able to provide.
Hi C.

This guy has produced a number of videos (so far #1 to #7).

He's up to the fitting of the new bearings into the crankcase halves (see #7).

These clips will give you a good idea of what you're up for.

They'll also give you a base from which to explore issues as they arise.

If you start with #1 you can work your way through them.




Cheers


R R
 

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And, of course, the incredibly long videos of lunmad which are worth watching to get a good idea how to begin.
 

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And for parts storage, the bottom half of egg cartons work great.

I like icecream containers, the plastic ones........but I don't eat icecream. My dog liked a dogfood that came in great plastic containers, I have a heap of them, very handy.
 

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Nice thing about egg cartons is they can be used to simultaneously group small parts according to section (carbs, rocker boxes, transmission, gearbox, etc) and also sort parts according to left/right (carbs, rockers, pushrods, etc).
 

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Ziplock bags

For now....they are changing....we can still get Coles/Woollies shopping plastic bags with the groceries. I usually degrease and wash everything, dry, hit with a smear of oil or petroil mix and then bag in the supermarket bags ready for reassembly. Its called recycling....all puns intended!!!
 

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Discussion Starter #19
Guys - thank you so much for your help with this. I am overwhelmed by your responses and there is a lot of info that I have to take in. I'm just about to take 12 months leave from work (and relocate interstate). Once the move has taken place, then I will settle in and begin the task of becoming familiar with my 69'. The bike used to belong to my father (passed away). He was the 2nd owner and was an 'A' grade mechanic. Unfortunately, I never took the time to learn from him. I tracked down the previous owner and managed to purchase the bike so it is now back in the family. This is definitely not a 'standard' 69 Triumph and I do not intend to try and rebuild it to resemble anything close to the 'original' condition, but rather to keep it as my father had it. Once I figure out to post pics on this forum, I'll add a recent photo of the bike.
 
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