New carburettors - one step back

It's already over two weeks ago that I got round to fitting the refurbished SU HS6 carburettors to my TR7 DHC. And I also managed to take the car for a ride to see how the new set up behaved. Overall pretty pleased with how the engine runs now! Pick up has been clearly improved, and the engine also revs much freer compared to the old set up. Sadly though there were also a few issues that have prompted me for some drastic action, removing the carburettors!

And the two reasons for this is that the choke mechanism doesn't function properly. Also the jet adjusting nuts on both carburettors are very stiff. Let's start with the first problem, the choke mechanism. Compared with the (original spec) carburettors that came of the car, the refurbished  ones have much more free travel before the jets are lowered and the throttle discs start opening. With the carburettors of the car the mechanisms could be compared:

It is clearly visible that the cam which activates the throttle disc is rotated slightly compared with the old carburettors. This results in the throttle disc not opening as far as with the original set up. And another choke related problem is that the bracket for lowering the jets is activated even later. So the jets are hardly lowered when the choke cable is pulled. The reason for this was more difficult to spot. But it turned out that the bracket that came with the overhaul kit has a slightly different shape that causes this:

The second problem was caused by the very stiff action of the mixture adjustment nuts. With the back plate of the air box in place it was almost impossible to adjust the mixture. The fact that newly supplied (non wax stat) choke's lever link is preventing good access to the adjusting nut doesn't help there. As a result of this fine tuning of the mixture was impossible. So after spending an hour or so in the shed, with the parts for the '76 FHC, I decided to use the newly plated carburettor parts that I prepared last year, together with the choke lever links from the old carburettors. To be continued!