The Triumph Dolomite Club - Discussion Forum

Isn't there normally more than one return spring attached to the bracket (yellow on Mahesh's car) above the inlet manifold?

Pippin wrote:Isn't there normally more than one return spring attached to the bracket (yellow on Mahesh's car) above the inlet manifold?

Early 1850 linkages had 3 springs, later linkage systems had 1 spring, I think Sprints are the same. This cut down on spindle wear.

Depends on carb. Ones that have a self return spring around the throttle shaft only need a spring on the mechanism. Carbs which don't have a return spring of it's own do need an external one.

Jeroen

Here a pic. In the red box you see the differences. You always need one returnspring per carb and one on the mechanism. So it depends on the carb howmany and what type of spring you have to use.

Jeroen

On the new manifold there is an extra threaded hole, is this for a vacuum gauge ?,
or am I missing something ?

For now I have just put a bolt in.

Yes, I suspect so. Aluns new Sprint at the NEC had one in the same place leading to the vacuum gauge.

Got bored with the bolt, so put a gauge in,

but even at idle it does fluctuate a lot between
the two points, (1/20th sec) rpm tacho is stable.

I don't think it's a vacuum leak at that speed of
fluctuation, more likely rotor or cap.

Must get going on the 123 dizzy.

You sure its not just registering the pulses you will get in the manifold at idle? I;d suspect it gets steadier at higher revs?

Dont forget it only fires on each pot every other turn...

Jonners

I straightened up the gauge this morning, and tweaked the mixture and idle, to reduce
the movement, this has resulted in the rpm settling and has smoothed
the engine a bit. (Something put on for novelty value actually done some good )

You are right Jon, it does smooth out somewhat at higher revs, and as it's a dry
gauge, twitchyness must be part and parcel, or so it seems.

Hi Mahesh, When I had my original Mini, I put all sorts of after market gauges in it. Including the very colourful Smith's vacuum gauge. Now this was supplied with a length of clear plastic pipe and something called a "restrictor " I seem to remember this had to be installed at the manifold end which had to be tapped 1/4in BSF and the idea was to remove vibration on the needle but not so much as to stop the rapid vibration due to weak valve springs. I'll see if I can find the details.
HTH,
Tony.

I have a 4 gauge set up for bike carbs and they have screw restrictors on each gauge pipe to stop fluctuations. Not normally needed on a shared manifold but maybe pinching the pipe with thumb and finger until it stops may prove it.
Tony

I'm just surprised that the gauge isn't day glo acid house pink!

Don't be putting ideas into his head. We've already seen his colour-coded axle stands.

Don't forget the yellow multimeter

So does this mean you have to have the bonnet cracked open so you can see it when you are driving?

Looks to nice a gauge to be wasted in the dark...

Jonners.