Britbike forum Forums Thread Like Summary - ‘79 T140E oil light flicker

Good evening
This is a new one to me .
A new Brit bike owner and friend did his first oil change on his new to him ‘79 T140E with low miles on it . (Indicated 7500)
He used Spectro mineral Heavy Duty 20w50 which is what I use in my ‘76 T140V .
Cleaned the frame screen and the engine screen .
On third start up with engine cold, the oil light flickers below 1500rpm.
Over 1500 the oil light goes out .
At idle, the oil light is solid on.
Before the oil change the oil light behaved normally .
Key on, light on. Engine start , light off .


Thanks in advance .
Curious in Clovis

You guys know your stuff, unlike those silly nits at Triumph.

I’d check the oil pump, clean it, reseat the balls.

There may be dirt under a ball valve.

And inspect the crank nose oil seal.

Brass (soft) has very poor wearing properties and would not be any good for a pump. They appear to be made of Gun Metal (Red Brass in USA), which is a type of bronze; an alloy of copper, tin and zinc. Its typically around 88% copper, 8–10% tin, and 2–4% zinc. It cast very well and was originally used chiefly for making cannons. It was also widely used for valves and fittings on steam locomotives and steam boilers and is much harder, stronger, wear and corrosion resistant than brass.
I see it regularly working on steam locomotive valves and fittings regularly at a heritage railway, It is a different colour (more gold coloured than yellow) like brass and I am quite familiar working with it.
A number of steam loco valves have steel (stainless) non return ball valves and the practice of seating the ball in the seats by a sharp tap with a drift is a normal practice and works well to seat restore a slightly worn seat.

The secret is to give the ball only ONE sharp tap, if its going to work, that is enough.

I haven't actually done this on a Triumph pump, but I see no reason why it should be any different.