T120V 5 Speed - Indexing, False Neutrals Etc

[Woollybandit]

Hi all. Just joined up after lurking during the rest of the 1971 or 1972 T120V rebuild but now come to the dreaded gearbox!
Its a leaf spring 5 speed which I think is original as the engine is stamped T120V. Although the V5 says it is a '71 I think a mistake was made on re-import from the States as the engine number CG50763 indicates it was a year later. Also the casting date on the rocker boxes say 71 which I believe means they were due for the 1972 market.
Indexing ….. need I say more?

So, which gear to index in? Which orientation is that chosen gear on the camplate? How to keep it in that position when pushing leaf spring/tranny inner casing in?
My cam plate is the type with three clear cut channels through the plate - very different in shape to the trough type one LUNMAD has in his 4 speed.

Six hours yesterday and have gears assembled but many false neutrals if the gear lever even wants to move. The shafts and forks are assembled EXACTLY as the book(s) says and show, the thrust washers are in place and fork pins are engaged in the plate ….. fork selector rod nicely home and snug.
Engine is on bench stand and no gaskets are in place yet. I can lever cam plate quadrant with outer cover off but things lock up often when gear change selector casing is on and nipped up.
Will take selector apart for the hell of it today although the action is fine off the engine ……. catch those pawls someone!
I will finish rest of engine and get it in frame with chain attached to sprocket as that might make moving around the gears easier. Maybe a miracle will happen and it fixes itself, although that’s never happened in my last 50 years riding and spannering!

Any advice sought.

 

[grandpaul]

I had a heck of a fuss getting the 5-speed in my Triton correctly, took 3 tries.

Now I need to replace the outer bearing and do it all again.

 

[Woollybandit]

I had a heck of a fuss getting the 5-speed in my Triton correctly, took 3 tries.

Now I need to replace the outer bearing and do it all again.

I’ve slept on it and decided if pushing the leaf spring in rotates the cam wheel then I'll try to pre-rotate the wheel clockwise so the spring can’t push it any further and assemble. Perhaps the leaf spring partially pushing the wheel to a nomansland position between gears and the foot lever then moving on to another mid gear position is what’s giving me lots of false neutrals.
Now that it’s all assembled without gasket and we’ll see how it goes after putting it in the frame and rolling around. Then whip in some oil and start it. If all ok pull it out again and refit with gaskets.
If not ok - drain, pull off outer casing, pull out inner casing 1/4” move quandrant one tooth and try again.
Simples!

I'm not averse to input from those out there with the answer …… before I run out of hand-cleaner.

 

[Woollybandit]

I had a heck of a fuss getting the 5-speed in my Triton correctly, took 3 tries.

Now I need to replace the outer bearing and do it all again.

Hey Grandpaul, did you remember what the solution was or was it just a lucky dip affair that worked?

 

[grandpaul]

Hey Grandpaul, did you remember what the solution was or was it just a lucky dip affair that worked?

The alignment has to be very precise, as the tooth is able to push one way or the other very easily. If it's all properly aligned before the teeth touch, and you give it one clean push exactly straight into place, it should slot right in.

 

[scottholl]

Hi all. Just joined up after lurking during the rest of the 1971 or 1972 T120V rebuild but now come to the dreaded gearbox!
Its a leaf spring 5 speed which I think is original as the engine is stamped T120V. Although the V5 says it is a '71 I think a mistake was made on re-import from the States as the engine number CG50763 indicates it was a year later. Also the casting date on the rocker boxes say 71 which I believe means they were due for the 1972 market.
Indexing ….. need I say more?

So, which gear to index in? Which orientation is that chosen gear on the camplate? How to keep it in that position when pushing leaf spring/tranny inner casing in?
My cam plate is the type with three clear cut channels through the plate - very different in shape to the trough type one LUNMAD has in his 4 speed.

Six hours yesterday and have gears assembled but many false neutrals if the gear lever even wants to move. The shafts and forks are assembled EXACTLY as the book(s) says and show, the thrust washers are in place and fork pins are engaged in the plate ….. fork selector rod nicely home and snug.
Engine is on bench stand and no gaskets are in place yet. I can lever cam plate quadrant with outer cover off but things lock up often when gear change selector casing is on and nipped up.
Will take selector apart for the hell of it today although the action is fine off the engine ……. catch those pawls someone!
I will finish rest of engine and get it in frame with chain attached to sprocket as that might make moving around the gears easier. Maybe a miracle will happen and it fixes itself, although that’s never happened in my last 50 years riding and spannering!

Any advice sought.

On my 72 T120TRV I sheared the main shaft on a power down shift, cracked in a typical 45 degree shear fracture right where the splines blend into the round shaft journal, So i was looking at my first experience of transmission remove repair and replace. i was lucky to find a used mainshaft. i followed the work shop manual and i succeeded in the R,R,& R. i think the single most important and helpful technique was using the chain connected routed over countershaft sprocket and around the rear wheel sprocket i also did NOT mount the clutch basket and plates etc. on the main shaft in the primary case. i left the gear box case open so i could diddle with the transmission and shifter plate. I was amazed that i was able to accomplish the R,R & R. If i has access (which i didn't) too a shot peener i would have brought the shaft and peened right where the splines blend into the round shaft journal. hope this is any help.

 

[speedrattle]

indexing the leafspring five speed on my 72 T120 used to give me fits.

the one-year-only 1972 shop manual says to rotate the camplate into first gear-- you can tell because the layshaft first gear will be pushed out to engage with the first gear locking dog-- and then push the inner cover on with the top edge of the second quadrant tooth from the bottom lined up with the center of the gearchange spindle hole. here's the book page

this procedure appears to assume that you have the box held rigidly so that it cannot roll out of position as the leaf spring rubs on the camplate. ive never done it but you could do this by temporarily fitting the clutch basket onto the mainshaft on the primary side. stuff a rag or something under the teeth so it cant spin.

i used to back the camplate up so that when i pushed the inner cover on, the camplate would roll into the correct position. but a couple of years ago i drilled out the bottom of the gearbox and installed an old-style spring-loaded plunger. indexing now is easy, first time, every time.

 

[Woollybandit]

Thanks SpeedRattle. With the help of a friend we managed to dry assemble correctly without gaskets by using a drift through the drain plug to hold cam plate position. Now have to do it all again with gaskets!
It's a pain having to wait for assistance so will give your method a try single-handed.
Just found that the PO has split the timing case at the pressure switch ..... grrrr!

 

[sikatri]

What does the split look like? Fixable?

 

[speedrattle]

it splits because triumph used two types of threads in there, straight and tapered, both the same pitch. you can break the case either way by screwing in the wrong sender unit.

 

[sikatri]

it splits because triumph used two types of threads in there, straight and tapered, both the same pitch. you can break the case either way by screwing in the wrong sender unit.

Can the split be welded?

 

[Woollybandit]

What does the split look like? Fixable?

I have ordered a replacement. Will try hylomar along the threads as an attempt at sealing it rather than risk the same happening to me

 

[sikatri]

View attachment 51078

I have ordered a replacement. Will try hylomar along the threads as an attempt at sealing it rather than risk the same happening to me

It’s on a cover?

 

[Rudie]

PO has split the timing case at the pressure switch

Can the split be welded?

It can be welded but might never be completely oil tight - the case has expanded around the hole, the thread will remain loose around the switch, sealant is likely to required ever after but might not always be successful.

it splits because triumph used two types of threads in there, straight and tapered, both the same pitch. you can break the case either way by screwing in the wrong sender unit.

The basic reasons for twins' timing covers split around the oil pressure switch mounting hole is modern incompetence:-

. Mechanically insensitive p.o. whose only reaction to a fitting problem is to use more force, instead of ascertaining why two parts that should fit together apparently do not.

. The switch maker certainly for around the last two decades to my certain knowledge has not been able to make either switch thread accurately consistently, some are oversize.

. Wholesalers (who commission the switches' manufacture) and most retailers who choose to continue to supply one switch with the wrong thread then blame owners (who, as above, can be their own worst enemies ...) for the consequent problems. I am sure there are some retailers who will claim not to 'know' this information, but that more points up the competence of people who can advertise themselves as "dealers"?

If a "PO" of the T120V of the thread title simply looked in the contemporary parts book and ordered a new oil pressure switch by the listed part number - D2133 - most retailers do not give a damn and happily supply a current production NPT thread switch, although Meriden certainly did not build any twin engines with NPT threads after October 1968 ...

Nevertheless, that in itself would not be a problem if the current switch maker could actually make them accurately consistently - 1/8"NPT and 1/8"NPS threads (without any "F", "M", etc. suffixes) have the same maximum 0.405" major diameter and NPT should taper downwards ... Or the wholesaler could refuse to accept switches that are not made accurately? Instead of leaving owners and retailers to sort out the problems and financial consequences? Heaven forfend ...

Then there is also fair amount of historical incompetence:-

. When Meriden adapted the original 650 timing cover oilway drilling/temporary pressure gauge take-off for the permanent oil pressure switch, material should have been added to the timing cover - the thread major diameter was enlarged from 3/8" to 0.405", any fool with eyes could see the resulting timing cover thickness was silly thin.

. Although there were only two different oil pressure switch threads, there were/are three different Triumph part numbers for different switches. All switches were made by Smiths Industries (as in speedo and tacho supplier) up to late 1978, when Veglia took over all. The non-controversial part numbers/threads are:-

.. D1943 (60-1943) listed for triples built before January 1969; has a 1/8"NPT ((US) National Pipe Tapered) thread.

.. 60-3719 listed for 74 on triples and twins; has a 1/8"NPS (National Pipe Straight - i.e. parallel) thread.

. The problem part number is D2133 (60-2133) listed for all twins 69-73, triples January 1969-end 73 and all singles. Afaict, this switch always originally had a 1/8"NPS thread:-

.. Unfortunately, despite putting D2133 in 69 twins' parts books, Meriden built some early 69 twins (some 650 DU prefix numbers, some 500 H prefix numbers) with NPT thread switches and timing covers, and listed a NPT thread blanking plug (E9526/70-9526) in the 650 parts book ... If any documentation explained this clearly at the time, it is not in the public domain now ...

.. Provision of outside suppliers' part numbers in Triumph parts books was dismally inconsistent:-

... the first 69 T150 parts book has the correct Smiths part number for Triumph D1943;

... the second 69 T150 parts book has Triumph D2133 but the Smiths part number is unchanged, although the switch changed ...;

... twins' parts books do not have the Smiths part number with D2133;

... so it it not hard for someone looking at 69 parts books and a switch out of an early 69 twin to extrapolate "D2133" has a NPT thread ... just that is wrong ...

... (aside, BSA used exactly the same switches, its parts book compilers were better and more consistent with outside suppliers' part numbers and at least one contemporary BSA workshop manual contains an explanation of the Smiths part numbers ).

1971 or 1972 T120V

The engine number date code will have a different year letter - 1971 = "E", 1972 ="G". Also, afaik 71 5 speed T120 were built only in June 1971 = "GE" engine date code letters and, unless a 71 T120 has had replaced restamped crankcases, the engine model code was originally "T120RV", the "V" stamped separately in a slightly larger font than the "T120R".

 

[Rudie]

That is not accidental incompetence, that is a PO who should not be allowed tools unsupervised ...

Or it might be a PO who fitted an oil pressure gauge sticking out from the engine ... before hitting it with the front fender the first time he turned the steering to the left ...

replacement. Will try hylomar along the threads as an attempt at sealing it rather than risk the same happening to me

I would not.

First find a good knowledgeable - likely bricks and mortar - Meriden Triumph spares dealer, who knows the difference between the threads I detailed in my previous post.

Then, depending on the "replacement" timing cover:-

. Assuming not from an early 69 650 with a tapered (NPT) pressure switch hole thread, the good knowledgeable dealer should sell you a 60-3719 switch - not listed before 74 but the only one today with the correct 1/8"NPS thread that Meriden built your engine with.

. Only use a modern D2133/60-2133 switch if the cover is from an early 69 650 with a tapered (NPT) pressure switch hole thread.

Whatever switch your are supplied and use, you should be able to screw it into the timing cover by hand with little force:-

. A NPS thread switch should screw right up to the sealing washer at the end of the thread, a wrench will be required only to give the switch a light 'tweak' just to squeeze the sealing washer between it and the timing cover.

. Alternatively, a NPT switch, depending how accurately it has been made, might not tighten all the way to the end of its thread. Ahead of discovering it leaks under pressure from a running engine, I strongly advise against 'trying' a wrench on the switch.

Whatever switch you use, do not be surprised if the switch leaks from elsewhere apart from the thread. As I posted above, modern switches are dismal quality ... eventually, you might cut your losses and use the timing cover hole for a hose to a gauge.

View attachment 51078

Do you have the broken piece?

When I wrote my previous post, I assumed "split" would be the usual tiny one in the thin timing cover wall outside the switch. Broken piece available, a skilled ally welder should be able to refix it? Even broken piece not available, said skilled welder should be able to rebuild the area, although an old/sacrificial switch might be needed as a 'core' - to avoid need to recut the thread in the welded area - and the welded area will need to be finished to blend it into the original casting.

 

[grandpaul]

You MIGHT just be able to Loctite an Allen plug in the hole until you get it welded up and fixed properly...

Then it would be on you to ensure you have proper oil & flow, etc...

 

[sikatri]

Definitely make sure the next threaded part matches the cover.

 

[sikatri]

If you have the broken piece, I’d get it fixed later. Never hurts to have a spare part.

 

[Woollybandit]

All good advice, thanks.
New cover arrived today and new switch hand threads in 3/4 of the way then nips up almost like it bottoms out.
The new primary casing is 70-7318 (broken one is 70-8797) with straight cut thread to suit 60-3719 switch. It has the swage milled for the 4 valve pump but fits perfectly.
I've found an old switch which runs into the hole to the washer so maybe I'll wet and dry the peaks of the new switch threads and see how it goes in - the old switch was 9.8mm OD whilst the new is 10.1mm ….. a bit tight.
Just don’t want to push my luck with the new cover.

 

[speedrattle]

That is not accidental incompetence, that is a PO who should not be allowed tools unsupervised ...

lol

that is exactly true