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Gearbox Question
#813608 06/22/20 9:28 pm
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SJS Offline OP
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My brake saga over, I've moved on to what was another issue, that of poor gear selection.
You could get them all but the action of the lever was stiff and it did'nt seem to return as good as it should.
All indications pointed to springs, plungers and a probable general clean up of the components involved in that procedure.
So, off with the kick start cover for a look and yep, fair bit of rust on the plate holding the plungers, the plungers themselves did'nt look too bad but I bought new of everything so replaced the lot, greased it all up and put back on.
Problem. Can't select gears ! Maybe one if I'm lucky.
The levers got a nice up and down sprung action to it now but turning the rear wheel and trying to get gears, somethings not right.
Had cover on / off a number of times, still the same.
Points to note:
1. The bike was in neutral when I took the cover off and thats the position when I'm putting it back on.
2. With the cover off and moving the gear lever by hand on the other side, should I still be able to select gears when I move it, cause I can't.
Surely the cover being on the other side is simply to provide the return action of the lever, not actually selecting the gears ???

I naively assumed this was going to be a fairly straight forward exercise !
Cover off, replace all springs and plungers, cover back on.
Ever wished you'ed just left things alone !

Any suggestion or pointers appreciated as usual.

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Re: Gearbox Question
SJS #813610 06/22/20 10:13 pm
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Originally Posted by SJS
2. With the cover off and moving the gear lever by hand on the other side, should I still be able to select gears when I move it, cause I can't.

No, because the cross shaft must be disconnected from the gearbox mechanism before the outer cover can be removed.


Originally Posted by SJS
Surely the cover being on the other side is simply to provide the return action of the lever, not actually selecting the gears ???

I don't follow your thinking as the selector return action is in the gearbox and not on the primary side where the gear lever is.

Re: Gearbox Question
L.A.B. #813612 06/22/20 10:31 pm
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Maybe a combination of my lack of knowledge and poor explanation.

I've disconnected the cross shaft as you say in order to remove what I'm calling the kick start cover.
I haven't touch the the other side ( primary ) cover.

To me ( not necessarily the reality ) the plunger mechanism, plate and curved return springs in the kick start cover is to provide the spring action up and down for the gear lever and to hold a position as opposed to being the mechanism by which gears are selected ??

I've reassembled everything to the reverse of disassembly ( photos taken and all ! ) but can't get satisfactory gear selection.

With the kick start cover off, should moving the gear lever on the opposite side ( primary ), be moving anything internally in the gearbox as opposed to simply "flopping" up or down freely ?

That doesn't seem right to me ?

Re: Gearbox Question
SJS #813614 06/22/20 11:37 pm
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Originally Posted by SJS
I've disconnected the cross shaft as you say in order to remove what I'm calling the kick start cover.
I haven't touch the the other side ( primary ) cover.

Ok.

Originally Posted by SJS
To me ( not necessarily the reality ) the plunger mechanism, plate and curved return springs in the kick start cover is to provide the spring action up and down for the gear lever and to hold a position as opposed to being the mechanism by which gears are selected ??

Well, the two angled plungers select the gear by moving the selector quadrant either up or down, the curved springs are the returns.


Originally Posted by SJS
With the kick start cover off, should moving the gear lever on the opposite side ( primary ), be moving anything internally in the gearbox as opposed to simply "flopping" up or down freely ?

No. Pedal movement turns the cross shaft via two toothed quadrants in the primary so if the cross shaft is disconnected on the gearbox side as it must be in order to remove the outer cover then there's nothing connecting the gear pedal to the gearbox selector mechanism so the pedal will 'flop' up and down within the 'stop' range of the quadrants.

Last edited by L.A.B.; 06/23/20 12:02 am.
Re: Gearbox Question
L.A.B. #813620 06/23/20 12:56 am
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Quote
With the kick start cover off, should moving the gear lever on the opposite side ( primary ), be moving anything internally in the gearbox as opposed to simply "flopping" up or down freely ?

[Linked Image from t160.jgweb.org]
yes ,
the upper right selector Fork , under the locknut ( attached to the Cross shaft )
... rotates the second selector Fork @ lower left .
the lower left Fork is connected to the selector dog pieces ... on the other side of the cover .
... using the short , keyed connecting shaft

(it sounds like a least one piece is missing from the assemblage ? )
like maybe part # 62 ... the key ?
[Linked Image from draganfly.co.uk]

Re: Gearbox Question
SJS #813621 06/23/20 1:09 am
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Maybe you have the plungers in the wrong way around?

Re: Gearbox Question
SJS #813629 06/23/20 1:43 am
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Or maybe you have the guide plate in back the front. The one that bolts to the inside of the outer gearbox cover. A common mistake.
Part No. 66 in the above exploded view.

Re: Gearbox Question
quinten #813648 06/23/20 7:21 am
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(Second try posting as the first got lost somehow)

Originally Posted by quinten
Quote
With the kick start cover off, should moving the gear lever on the opposite side ( primary ), be moving anything internally in the gearbox as opposed to simply "flopping" up or down freely ?

[Linked Image from t160.jgweb.org]
yes ,
the upper right selector Fork , under the locknut ( attached to the Cross shaft )
... rotates the second selector Fork @ lower left .
the lower left Fork is connected to the selector dog pieces ... on the other side of the cover .
... using the short , keyed connecting shaft

With "the kick start cover" (item 2, below) "OFF" then the parts in the photo won't be there as the cross shaft, item 35, must be detached from the link, item 36 (what you appear to be referring to as a "fork") before the "kick start cover" can be removed, therefore, with the kick start cover off, nothing will move inside the gearbox when the gearchange pedal is moved.

The circular linkage inspection cover, item 10, I wouldn't consider to be the "kick start cover" unless that's what SJS actually means but I don't think so.

[Linked Image from i.postimg.cc]

Edit:
If the link, 36 has been detached from the cross shaft then it must be refitted at the exact same spline position again, if not, (although the primary cover has not been removed so the quadrant teeth shouldn't be mistimed) the primary quadrants (item 40 and the gearchange spindle quadrant) may not be centralised so pedal movement can be restricted in one direction.

There's a hole in the clutch lifter compartment to check the pedal spindle quadrant is positioned correctly.

See manual, section D5, Fig. D7, RH drawing.
http://www.classicbike.biz/Triumph/Repair/Trident/1975Triumph-T160.pdf

Last edited by L.A.B.; 06/23/20 8:42 am.
Re: Gearbox Question
L.A.B. #813652 06/23/20 9:59 am
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I think you have now articulated the hunch I was getting at with the above scenario, namely something wasn't engaging elsewhere else along the lever shaft mechanism.

As I was originally disconnecting the cross shaft link, I was thinking, should I have marked the spline position. I did'nt !
Thats the only area of doubt that I've subsequently had in knowing where the exact position of the gear-lever was prior to dismantling.

I did subsequently think that by manually moving quadrant 9 to select 1st gear and then letting the gear lever fall to its lowest position, ie selecting first gear and then fitting the spines in that position, that might then take the "guess work" out of it but obviously not.
I shall follow the procedure to check the gear change spindle quadrant but what you are saying is that the positioning of the splines really is critical ?

As an aside and like I say, I photograph stuff before I disassemble and upon removing the kick start cover as I call it, I photographed the plunger plate set up before removing the 4 securing nuts.

I subsequently stripped out that little assemble for replacement new parts.
After thorough cleaning and a couple of days later waiting for some further parts, I go to reassemble the new parts.

I look back at my photos and notice that the upper plunger had been installed with the "cut out" facing the plate 66 and not the chamfered edge which would then logically follow the underside chamfer of the plate.
This went against my basic engineering radar as how could the plunger be depressed by the chamfer in the plate when "in action".

After loads of checking of manuals, books and photos on line, I ignored my original photos and installed the plunger effectively facing the other way around, ie the correct way so that the movement of the shaft 60 and subsequent force would mean that the mating chamfers of the plungers and securing plate would then depress the plungers in either direct which indeed is where we are at now.

What I can't understand is how it worked as it was assembled before my disassembly.
If I could figure out how to upload a photo to show this, I would.

Re: Gearbox Question
SJS #813656 06/23/20 10:36 am
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Originally Posted by SJS
I did subsequently think that by manually moving quadrant 9 to select 1st gear and then letting the gear lever fall to its lowest position, ie selecting first gear and then fitting the spines in that position, that might then take the "guess work" out of it but obviously not.

As the inner cover wasn't removed then the selector quadrant, item 49 on the right-hand diagram that quinten posted (I don't know why quinten posted the '72 gearbox diagram on the left?) would still be correctly timed regardless of whichever gear position it was at when the outer cover was refitted so shouldn't have been the problem.


Originally Posted by SJS
I shall follow the procedure to check the gear change spindle quadrant but what you are saying is that the positioning of the splines really is critical?

Yes, the cross shaft quadrant must be positioned correctly relative to the link.

If it isn't, then the cross shaft quadrant won't be positioned correctly (correct in the photo, below) as a result, the gearchange spindle quadrant would also be set off centre and likely to hit either the top or bottom travel 'stop' before the gear is fully engaged.
[Linked Image from i.postimg.cc]


In the photo below, the gearchange spindle/pedal quadrant is at the top limit, the stepped casting lug is the lower stop so the quadrant must be positioned midway between the stops using the hole in the lifter chamber (not visible in the photo) before the link is fitted to the cross shaft.

[Linked Image from i.postimg.cc]



Originally Posted by SJS
I look back at my photos and notice that the upper plunger had been installed with the "cut out" facing the plate 66 and not the chamfered edge which would then logically follow the underside chamfer of the plate.

If one plunger was facing the wrong way then that was almost certainly causing the problem.

Last edited by L.A.B.; 06/23/20 10:38 am.
Re: Gearbox Question
SJS #813685 06/23/20 4:20 pm
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Originally Posted by lab
... As the inner cover wasn't removed then the selector quadrant, item 49 on the right-hand diagram that quinten posted (I don't know why quinten posted the '72 gearbox diagram on the left?)...

i had to see if you were paying attention .
no ... posted because , I'm just a sloppy resource librarian ... the image was snagged from dragonfly parts .
their images are often more generic to cover multiple model years .
You get the 72 as a free bonus .

Last edited by quinten; 06/23/20 6:05 pm.
Re: Gearbox Question
quinten #813686 06/23/20 4:22 pm
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"kick start cover " ... > I read this differently
...as the " inspection cover " on the "kick start side ".
[Linked Image from triumph-spares.co.uk]
when you lever the cross-shaft on the primary-side ( or gear-shift )
... the action is transfered and visible ...under this cover on the timing side

if " Kickstart cover removed " means " the whole outer cover assemby "... [Linked Image from cdn.myonlinestore.eu]
it contains all the important parts that control " the range of travel of each gear ratchet "
...and the 2 springs that return the ratchet dogs to the ready , middle position .
so these bits are the smart spring loaded parts ... the other shafts , cross-shafts and numerous forks are just the linkage
to get to the action here .
[Linked Image from cdn.myonlinestore.eu]
with this assembly removed ... the shift cross-shaft will " flop around "

sorry if this has led to any confusion .

Re: Gearbox Question
SJS #813691 06/23/20 5:35 pm
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Right, think I'm on the same wave length now. Thanks for assistance as usual.
Just waiting for some new cover gaskets to arrive to give it another bash ...... metaphorically speaking !

Re: Gearbox Question
SJS #814561 06/30/20 4:22 pm
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Right, me again !

So, in response to above recommendations, I've removed the filler / inspection plug on the Primary cover / clutch side along with the cover on the clutch cable mechanism.

If I move the gear lever up and down ( disconnected from the kick start side ) I can see that the quadrants on the inner and outer casings are obviously engaged and operating, as any movement of the gear lever can be felt instantaneously on the cross shaft if you poke a finger through the inspection / filler plug.
No play whatsoever, all smooth action, instant movement from gear lever to cross shaft, so I can't see any issues there.

So surely this is simply a question of setting the lever in the correct position relative to neutral ( thats the position it was at at point of original dismantle ) and holding that position whilst refitting the kick start cover and alining the splines in the link 36.

The million dollar question is, what is that position and how do you find it without trial and error guess work ?
I assume its a definitive position for all T160's ?
On other old bikes I have, there is a gear indicator position to assist this exercise using a fixed scribed mark on the casing and a marked up splined disc indicator of the gear lever, simples !

I've tried looking at photos of T160's on line to get an idea of the angle of the gear lever in what I'm assuming are parked in neutral bikes but its still effectively guessing.

Can anyone give me a datum point on the Primary cover that follows through the line of the gear lever in the neutral position if you placed a straight edge on top of the lever or am I barking up the wrong tree with this approach.

Thanks in anticipation.

Re: Gearbox Question
SJS #814563 06/30/20 4:50 pm
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Originally Posted by SJS
So surely this is simply a question of setting the lever in the correct position relative to neutral ( thats the position it was at at point of original dismantle ) and holding that position whilst refitting the kick start cover and alining the splines in the link 36.

The million dollar question is, what is that position and how do you find it without trial and error guess work ?
I assume its a definitive position for all T160's ?

With the clutch lifter cover removed, position the gearchange lever so the upper edge of the gearchange quadrant (arrowed) is visible in the inspection hole then fit the link to the splines on the opposite side with the 'fork' centred whilst keeping the edge of the quadrant as close to the centre of the hole as possible.

[Linked Image from i.postimg.cc]

[Linked Image from i.postimg.cc]

Last edited by L.A.B.; 06/30/20 4:53 pm.
Re: Gearbox Question
SJS #814709 07/01/20 7:00 pm
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Brilliant, thats easy to follow.
As an aside and unless I'm mistaken, I have not seen this detailed in any workshop manuals.
Which if you were rebuilding an engine / gearbox from scratch, is quite critical.

Anyway, thanks again for your help.
I might just get to ride this bike again before winter arrives !

Re: Gearbox Question
SJS #814712 07/01/20 7:32 pm
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... just wondering out loud ,
Doesn't the t160 have a neutral safety switch ?
and wouldn't this equate to in an assembly position ?

Re: Gearbox Question
quinten #814721 07/01/20 8:17 pm
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Originally Posted by SJS
As an aside and unless I'm mistaken, I have not seen this detailed in any workshop manuals.
Which if you were rebuilding an engine / gearbox from scratch, is quite critical.

Agreed, the information in the T160 manual is less than satisfactory.



Originally Posted by quinten
... just wondering out loud,
Doesn't the t160 have a neutral safety switch?

The T160 has a neutral switch. I'm not sure what you mean by "neutral safety switch"?


Originally Posted by quinten
and wouldn't this equate to in an assembly position?

Not sure what you mean? The neutral switch is triggered by the T160 camplate when the gearbox is in 'neutral'.

Re: Gearbox Question
SJS #814726 07/01/20 8:54 pm
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Re: Gearbox Question
L.A.B. #814730 07/01/20 9:37 pm
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never mind , just thinking out loud .
and on the wrong index ... does not apply here .
on a complete tangent , i was wondering about
using the neutral switch to index and assemble the gearbox . .. not the linkage .

Quibbling verbiage over whether the neutral-switch is a safety-feature
isnt worth pursuing .

i do like the primary side linkage index trick though ... looking at the pics , it took a while for it to click .
the small inspection hole into the primary
"sees" the position of the backside top of the outermost linkage quadrant .

Last edited by quinten; 07/01/20 9:40 pm.
Re: Gearbox Question
quinten #814736 07/01/20 10:04 pm
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Originally Posted by quinten
never mind , just thinking out loud .
and on the wrong index ... does not apply here .
on a complete tangent , i was wondering about
using the neutral switch to index and assemble the gearbox .


That might work on a late T140 (E etc.) as the neutral switch is triggered by the selector quadrant and not the camplate as it is on the T160.


Originally Posted by quinten
.. not the linkage .

The gear indexing all takes place inside the T160 gearbox the same as other Triumph triple 5-speed gearboxes.

The cross-shaft, linkage and primary quadrants play no part in the indexing of gears.

Last edited by L.A.B.; 07/01/20 10:29 pm.
Re: Gearbox Question
L.A.B. #814851 07/03/20 5:14 am
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Originally Posted by L.A.B.
The gear indexing all takes place inside the T160 gearbox the same as other Triumph triple 5-speed gearboxes.

The cross-shaft, linkage and primary quadrants play no part in the indexing of gears.
Yes, but if you get the crossover linkage wrong it has the same effect as getting the indexing wrong.
Where's my fifth gear?


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Re: Gearbox Question
DavidP #814859 07/03/20 7:55 am
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Originally Posted by DavidP
Originally Posted by L.A.B.
The gear indexing all takes place inside the T160 gearbox the same as other Triumph triple 5-speed gearboxes.

The cross-shaft, linkage and primary quadrants play no part in the indexing of gears.
Yes, but if you get the crossover linkage wrong it has the same effect as getting the indexing wrong.
Where's my fifth gear?


Setting the quadrants incorrectly would restrict pedal movement in one direction as the pedal quadrant would hit either the upper or lower stop before the gear was fully engaged which would affect all gears either when changing up or changing down.


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