Size of Jets for 1984 Daihatsu Charade G11 Turbo Carburettor

You won't need to change the jets. We have had the Cb60 pumping 75- 90kW on the stock carby. Are you trying to increase performance there are better ways: e.g. RHF5 series turbo, lightened flywheel (4.5kg) with Mazda 121 clutch plate and 1600lb pressure plate. Swap in a G202 electronic dizzy& coil, and replace vacuum advance diaphragm.

Carby hat looks like this:

My '84 Charade G11 Turbo's rev counter exhibits some strange properties.
Most of the time, it works perfectly, and then it will creep slowly round the dial to rest on the bottomside of the pin.....suddenly it will shoot back to where it should be.....earthing problems, you think? On my wiring diagram there is a "filter" in the circiut. What is this item and where is it situated?
Thanks
Howard