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Off to the welders tomorrow for the swing arm pivot reinforcement and a spurious PO 1/8 screw hole in the headstock that penetrates the spine tube to be welded up. Why would you drill a hole up there?
A grease nipple perhaps? In my off-roading days it used to be a common mod so the entire headstock could be packed with grease to avoid having to take it apart to re-grease the bearings.
 

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Discussion Starter #62
Hi Chris, my use of the term 'headstock' was maybe a bit misleading. The hole is in the gusset plate that bridges across the headstock tube, the spine tube and the downtubes. Someone has drilled a hole through the gusset plate into the spine tube. Normally that probably would not matter as that part of the tube is just air space above the oil surface, and there's a spigot a bit lower down which takes the breather tube that goes along the rear mudguard - so the hole does not do anything. But since the welder's got his tools out, I'll get him to bung it up too.
 

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Hi Andy,

engine
casings have been vapour blasted.
Barrel bored +40 and 7.4:1 Harris pistons supplied. Big ends reground -10
Just as a matter of interest, did/do/will you check-clean crank and case oilways and cylinder bores?

Test fitted the crankcases and the engine plates and it all goes together without any need for hammers of any sort, let alone big ones.
Looks like the frame is OK and not bent.
Mmmm ... without wishing to rain on the parade, ime this isn't any guarantee that steering head and/or swinging arm pivot aren't misaligned. :( When I've had frames jig-checked, the jig owner has always required at least the crankcases fitted and bolted up (on dry-frame Triumphs, I prefer to use the complete engine, because it was only the very last that didn't also have head-steadies as standard); the reason I've been told is that, especially when the engine is secured in the frame, it prevents misalignment of the frame around the engine when the frame is straightened and, by definition, when it was bent originally.

Hth.

Regards,
 

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Discussion Starter #65
This head?

We are just about at the bottom of the curve - everything stripped, some things cleaned, specialist stuff mostly done.

Tiger 750 head was stripped and vapour blasted.

Thoroughly de-gritted to remove all traces of machining/lapping muck from the valve guide area (Stuart!).

All new valve guides, valves and springs (LF Harris), valves professionally lapped by machine shop. Not me!

Should get frame back end of the week, or next Monday. It's with a frame builder/repairer for minor damage fettling and the swinging arm pivot reinforcement, and repairing of a cracked lug on the DS crankcsae.

Swinging arm off to machine shop shortly for new bushes to be fitted and line reamed as necessary. Both bits then go for chemical dipping and powder coating.

Wheel builder rang to say half of the front wheel spokes were seized so better to re-spoke - so it'll be 2 wheel re-builds with polishing of rims and hubs. And a big bill........ again.

Pics have been in short supply as there's not been much to see - I am in the doldrums of bits being off at workshops having things done that I neither have the skills or the tools to do myself. I (more or less) know my limits, and getting older, I'm not as brave as I used to be, but at least now I have a bit of spare cash to cover up my mechanical deficiencies.

But, as GPZ needs photos!:

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Should have the DS crankcase back by next Monday so bottom end build will commence (with photos), with lots of flushing of oil passages and bearings/bushings with brake cleaner.
 

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Discussion Starter #68
Thacker washers........

Just re-assembled the inlet side rocker box. I've done these before, and they don't get any easier.

What's the trick? And the first person to volunteer the answer "Patience" will be off my Christmas card list.......

Triumph can't have spent an hour on each one - or maybe that's why they went bust. Bet Hinckley do it differently.

Mind you. I got more practice than expected because I left off the tool for getting the O ring into the housing the first time. At least when I tapped the shaft home there was no sliver of O ring left outside - so it looks like the tool works at least until that first seep of oil that is......

And yes, the plain washers are next to the ali to stop the Thacker washers eating into the housing. And yes, there's loads of oil on the shaft, and the oilways are very clean.

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Discussion Starter #69
More progress - the wheels are back.

I asked my local wheel builder to do what needed to be done - at least to make them look better.

He had to re-spoke them, and in doing so vapour blasted the hubs and polished the chrome rims. The rear wheel had the hub in backwards (so the drum effectively should have been on the timing side).

So, I now have 2 shiny wheels, both with new butted spokes (so they taper towards the rim) and all straight and true.

I have all new bearings and dust shields etc ready to go in.

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Hi Andy,

The rear wheel had the hub in backwards (so the drum effectively should have been on the timing side).
This I'm curious about?

The threads on the standard bearing "Locking ring" (brake side) and "Speedometer drive ring" are such that turning the wheel in the normal direction will always tighten them - the "Locking ring" has a normal right-hand thread, the speedo. drive ring has a left-hand thread.

If the wheelbuilder means these threads are reversed, you've a truly 'rocking-horse poo' hub - the only ones that BSA/Triumph made this way were for the ill-fated Fury/Bandit ...

Because this range was intended to spearhead BSA/Triumph's fight back against the Japanese, especially in the US, two things they were to have were left-foot gearchange and right-foot rear brake. Both were achieved by fitting the gearbox 'upside-down' to the 'normal' way, that placed the final-drive sprocket/chain on the right (what we normally refer to as "the timing side"); both brakes were to have been the new-for-'71 conical hubs but, with rear brake on the right with the final-drive sprocket/chain, the brake-side bearing "Locking ring" has the left-hand thread (same as a front conical) and the speedo. drive ring has the right-hand thread.

Regards,
 

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Discussion Starter #71
Hi Stuart - essentially the rim was on the wrong way around on the hub - side for side. I'd noticed that the spokes were all slightly bent (I've built bicycle wheels so I know a little bit about them). The hub's fine, the wheel had been re-spoked in the not too distant past, but whoever did it put the rim on the wrong way around.
 

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Hi Andy,

rim was on the wrong way around on the hub - side for side. I'd noticed that the spokes were all slightly bent
wheel had been re-spoked in the not too distant past, but whoever did it put the rim on the wrong way around.
A Paul posted earlier in a different context, "Ah so" ... :cool:

Thanks for clarifying. :)

Regards,
 

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Discussion Starter #73
This is the frame after having the s/arm pivot mount reinforced, as per advice from Don et al.

Just awaiting the return of the s/arm from having new bushes fitted and reaming to suit, then the black bits will go off to chemical strip and powder coat.

The welder (a motocross frame builder) had a good look over the frame and reckoned it was 'a good 'un'. He did tidy up a few other minor dings but there are no structural issues and it all appears straight - we had some straight edges over it and checked the obvious alignments.

He did say though that the plating for the rectangular sump at the base of the spine tube was thin - only about 0.75mm. This is just the way it was made, so welders beware.


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Discussion Starter #75
Ah, yes, the "Big D" frame reinforcing scheme. Well done.

They also do a few upper cross braces, but that's for racing...
It'll be a rare occasion if it goes over 50 now! Plenty quick enough for me.

FWIW, I've just measured the difference in height between the top of the rectangular sump and the centre of the bracket that holds the ali air box casting. 330mm on the T120R (so the early OiF), and 315mm on the 73 OiF. That will nicely allow me to hook up the carb to the airbox with the stock rubber boot. Problem solved I think (at a price!)
 

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Nice welding. So the re-enforcement strengthens the round oil tube between the swinging arm bearing mount and the base of the tube? Is that a common area of weakness that was never fixed by the factory?
 

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Discussion Starter #77
Thx Chris, but it should be! This guy is ex Air Products (Ruabon) - they used to make huge compressed gas tanks that went all over the world. He's competed all over the world in welding 'Olympics' and picked up medals. He can weld anything. Brilliant guy. He also welded a cracked lug on the DS crankcase - can't see where he's been. Whilst he does make one off fabrications, he's a reputation for welding where real skill is needed. Specialises in motocross machines.

TR7RVMan (I think it was) posted some photos of the stock repair to the earlier OiF frames. AIUI, the s/a pivot moves (but difficult to see how as it's fixed to the frame at both outer ends - but apparently it does) and then cracks at the spine tube, and you get an oil leak. Apparently, the factory fixed this later.

There's also a stock fix to stop the c/stand mounting tube rotating too - but this frame has the factory reinforcement already. It's interesting to stand the early (71) OiF and the 73 OiF side by side and look for the differences.
 

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Discussion Starter #78
We are now properly into the re-build.

I had a new sludge trap fitted to the flywheel, but then thoroughly flushed out the crank oilways with a full 2 cans of brake cleaner. Took many squirts to get the effluent to run reasonably clean and there were many sparkly bits in the oil ways - the remnants of the partial piston seizure I suspect. Then pumped a load of engine oil through the oilways and out of the ports in the big end journals.

The rods had been thoroughly checked by the workshop and pronounced serviceable, and the big ends reground to -10 thou. They were shot, even though there was no discernable play on the journals and the engine had showed no signs of knocking. Made sure everything was clean and fitted the new shells, oiled them up and torqued down the caps with new bolts and nuts.

Fitted the drive site roller bearing after heating in the oven for a few minutes. It dropped over the crank journal and soon shrank into place. The timing side ball bearing was already in the crankcase but would not let the t/s crank journal through, so warmed up the bearing with a hot air gun and it soon allowed the crank to drop into place.

Selected enough crankcase joining bolts ready and did a dry fit to make sure I could get everything back in place, then put two coats of Wellseal on the crankcase mating surfaces. The photos shows the first coat. Thoroughly oiled up the camshaft bushes and te mains and then assembled.

Bother. I had previously checked that the two long bolt/stud that connect the halves just in front of the gearbox would screw in Ok, but when I came to assemble I was not convinced that the stud had gone in far enough, so pulled it all apart. The stud was fully home, so added a third coat of Wellseal around the circular face around the crank and re-assembled. A bit of a faff getting the camshafts to drop into their bushes but easy enough.

Checked that the two halves were fully home and nipped the case up with some bolts. It's nipped up and a lot of Wellseal oozed out, easily cleaned up with acetone. I have not fully tightened the bolts in order to let the Wellseal go off a bit and I'll finally tighten the joining bolts in the morning.

Checked for crank and camshaft rotation, all is free. Checked the barrel seating surface for flatness at the joint, all OK. If it's going to leak oil, it won't be through the crankcase joint. I hope never to see the inside of that crankcase again.


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Discussion Starter #79
Dry fitted the gearbox to see that all is OK before proceeding further. What a battle....

I have the downloaded manual and a parts book for the 73 TR7RV/T140 - so that should be OK. No it's not.

Whilst I thought I'd cable tied together all the mainshaft and layshaft parts, in their correct order on dis-assembly, I was now doubting myself as one or two parts didn't look to be in their correct order. No matter, a good opportunity to understand how it all works, rather than blindly re-assemble it.

Fifth gear and the sprocket were already in - I had the shop change the bearing and seal.

Dropped the g/b main shaft in and 4th gear, and then the mainshaft 4th gear selector fork. This is the one shown in the parts book (#22) with a cutout on the inboard end of the boss that the selector shaft passes through. You'd think that the cutout is necessary to clear 5th gear.

No way on this planet was that selector fork going to fit. No way could I get the fork to fit in the 4th gear fork groove and the knob fit into the selector plate slot, such that the selector shaft could be inserted. No chance. The angles were all wrong.

There are no part numbers on the forks. There is only one other fork that it could be - the parts book layshaft 1st gear fork has a smaller diameter knob to fit in the narrower slot on the selector plate. So, the 4th gear selector had to be one or the other of the two shown in the parts book with the larger knob that fits in the wider of the two selector plate slots.

On a whim, I tried the other selector fork - this should be the layshaft fork according to the parts book. Doddle. Dropped right in. Simples. It does not have the cutout in the boss at the inboard end, ostensibly to clear 5th gear - but it does not need it. Loads of clearance.

Carried on and assembled everything else in about 10 minutes flat and loose fitted the g/b inner cover to keep it all in place and the muck out. It all dropped in, and it all seems to mesh OK. Everything rotates, and the various pinions are free to move along the shafts.

I did it all dry, on the bench, to check everything but it won't readily change gear because everything's bone dry and I've got it laid on the d/s side - so the gears have to move vertically - it needs oil - but I've no doubt that it's all gone back in as it should.

So, what's with the 4th gear fork as shown in the parts book ( item 22)? Is this another example of a parts book error?

And, several of the pinions had slightly different part numbers on them - usually by one or 2 numbers. Is this another example of the parts book? That or someone's been here before me with updated parts.

The g/b worked just fine before I stripped it - I did 1000 miles with it this summer with no major issues so I know it's serviceable.

I'm going to leave the g/b alone now until I get the frame back from powder coat. Once I've got the engine in the frame, I'll oil up the gearbox and index the change, and then make sure everything's working as it should.

And I didn't forget the layshaft thrust washers......

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Discussion Starter #80
In for a penny.....

Gearboxes may be complex, but AIUI, they should just slot together like Lego, if you get everything in the right place and in the right order.

Tappet blocks are another matter. Never taken these out on any of my Triumphs - they haven't leaked and if it ain't broke.....

However, the vapour blasters had taken one of them out when they painted the barrels, so I decided to take the other out, and renew the O rings, which proved to be hard and brittle.

Reading up, I was forewarned that the drifting tool was essential, and I bought one. Glad I did. The tappet block they left in was well tight, but I felt OK in drifting it out. I was nervous though - I don't like hitting cast iron in any form, it has a habit of snapping like a carrot without warning.

Changing both O rings took no more than 10 minutes, so an easy job. However, cleaning the glass media left over from the vapour blasting from out of the cylinder head bolt sockets and generally around the casting took a lot longer. I know vapour blasting does a good job, but it gets everywhere. I was particularly careful to make sure the exhaust tappet oil feed was clean.

This engine is going to have filters on both the feed (in the sump) and return oil lines (the Norton-type) and I'll be changing both at about 50 miles I suspect. Then 100 miles, then 150, etc etc....

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