moving on...1978 T140 hard shifting

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+1 on what LAB sez...

This is why Triumphs of this era should only use engine oil that is suitable for wet clutches.
Don't Triumph twins have holes drilled into the crankcases on their unit twins so that the primary oil always gets fillrd up to the bottom level whe engine is running?
 
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Thats from 1970 on ( and BSA's )

' Friction Modified ' oils modified the friction - of the clutch . To its detriment . GTX in 1970 WAS ' Friction Modified ' But likelys been altered a half dozen time since .
Was a C R I Castrol 40 wt. Non Detergent petrol / diesel / turbo oil , which was just the thing for ' large cylinders. Used for V-8 circuit racing .
So the irdots changed it to 30/40 multigrade . In N.Z. anyway . May be worth checking out though . Castrol . They even changed their CASTOR to 30/40 there ! .:(

Brings us the story of ' Detergent oils ' introduced to ' De Coke ' in service . ( previously you needed to pull the head periodically to ' De Coke )

These oils ' De Coked years of buildup , from one end of the country to the other . Engine Rebuilders became very wealthy men , around 1960 .
 
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Fast Eddie

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Don't Triumph twins have holes drilled into the crankcases on their unit twins so that the primary oil always gets fillrd up to the bottom level whe engine is running?
Yes, and they have no oil seal against the main bearing. So the primary and engine oil will always mix, hence the need to use the same oil in the engine and primary and ensure it it suitable for wet clutches.
 

Fast Eddie

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Is Castrol GTX 20/50 compatible with wet clutches?
According to Comnoz’ brilliant oil testing, yes. See the test thread here:https://www.accessnorton.com/Oil-Tests/NortonOil.php

However it doesn’t handle heat well and won’t stay good for long in a hot and stressful engine. And T140s do run quite hot. The BEST oil for a Triumph IMHO, based on that testing, is the Bel Ray 10-50 V Twin Synthetic.
 

L.A.B.

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Is Castrol GTX 20/50 compatible with wet clutches?
Castrol GTX 20W/50 is now a modern 'car' oil.

The correct oil would be to JASO MA/MA2 standard.
 
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I changed the oil to 20-50 Valvolene guaranteed good for clutches.
Backed off on the clutch nuts so now the lever is tolerable and gets full pull. Ran the bike up a steep hill in third to see if it would slip. So far so good.
Drained the very stinky GB oil and added shockproof lightweight oil (blue) .
Added a washer under the GB plunger. Shifting is easier but still near impossible to find neutral when hot and running.
I put in new fiber plates but for some reason I have to kick them free every day. that condition usually presents itself after a few years and new plates cures the problem for another few years.
The shift throw is very short, neutral from first is almost imperceptible.
Is there any way the crossover shaft or linkage could be binding? There is no free play in the shift shaft when I pull/push on it.
Tomorrow I will put some slack in the primary chain and see what happens.
 

L.A.B.

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The shift throw is very short, neutral from first is almost imperceptible.
I would have said that was normal for a left foot change T140 as the pivot point is some distance away from the footrest and the pedal is short resulting in a short, heavy throw and can be worse for a rider with normal or smaller than normal size feet. The shortness of the throw can make neutral selection difficult.

Is there any way the crossover shaft or linkage could be binding? There is no free play in the shift shaft when I pull/push on it.
There's no actual "linkage". Does the pedal initially move up and down freely (allowing for the heavy return action)?
 
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It seems that I will have to accept some heavy foot shifting and hit-or-miss on Neutral while hot. I talked with Jaye strait about this and he offers a full routine that takes about 8 hours of work to improve clutch and shifting. More later.
 
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update....I have been putting miles on the Triumph and it seems be shifting easier and neutral is easier to find.
 
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