Venting radiators

[dave bushell]

We all know, or should, to lean the bike over to the left to allow trapped air in the left hand header tank to escape when filling the radiator. Would it not make more sense to have the overflow pipe on the left instead of near the filler cap? That way any trapped air would be vented automatically when filling!
Dave

[BRIAN MARSHALL]

I have an old Dirt-Track Model radiator that was fitted to my sprint bike. It has a smallbore pipe, (same diameter as the overflow pipe), connecting the two halves of the header tank. I’ve no idea if it is original though !
Brian

[Stan Thomas]

There should be an internal inter-connecting pipe in the radiatior which automatically vents the L/H header. It is most important that it is in place, not only to allow the L/H header to fill properly, but because if it does not, when the trapped air in the L/H heats and expands, it forces coolant out via the overflow pipe.

Check this out on your rad – and also check the rad is earthed to the frame.

Stan Thomas.
Professor of snow-sweeping technology.
H.M. Borstal. Penkridge.

[dave bushell]

Stick to snow sweeping Stan, I tried earthing the rad but the dirt clogged the honeycomb and It ran even hotter but the worms were nicely cooked!
Dave

[Stan Thomas]

In the valley of the blind, a one-eyed man is king.

[dave bushell]

Whilst replacing dented end caps with new caps, I had the opportunity to look inside the header tanks of a 1930s rad produced by Norther Radiators and there was no evidence of an inter-connecting pipe between the header tanks.

[Stan Thomas]

I have three brand new unused “Northern” radiators – two have inter-connecting pipes, and one does not. As they were supplied to the Scott factory for three pound ten shillings a chuck, I suppose it was down to the individual on assemby who was probably on piece work and/or having a fag at the time…………………

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