[TR] TR4A - Balancing Carbs Oddity

[Q]

You may want to check that the pistons did not get swapped from one carb to the other.  While the piston itself is a generic fit part there is a height adjustment at the bottom of the piston, a small brass area if I remember correctly, that sets the stop height of the piston at idle.

I had a set of TR4 carbs come back from the rebuilder in such a condition.  The telltale was that with the engine stopped and the air cleaners off I could see that the gap below the piston was different on the two carbs.  Swapping the pistons made the gaps equal and cured all the strange idle problems I was having.

Edward Hamer
Petaluma CA