Carb strange problem

[BSA500]

Hi,
 On my A7 I have noticed a strange tickover 'issue'.With my hand on the throttle and pushing it fully closed I have a normal tickover lets say 900rpm for argument(no tacho).If I then gently take up the cable slack(not alot) the tickover drops quite low nearly stalling then as I open the throttle picks up as it should.Not really a huge problem but curious to see if its normal?.The carb does not appear worn and is correctly jetted.
Andy

[beezalex]

What you describe is a typical symptom of a worn slide.  You could also potentially have an air leak.  Two ways to check for this:  (Messy) spray some carb cleaner at the joint to the head and the carb top. (Clean) hold an unlit propane torch near the two "leak prone" regions.  If the rpms change at idle, you have an air leak.

[Triton Thrasher]

You may be able to tune it out by holding the throttle at that "bad" spot and twiddling the pilot mixture screw until it fires properly.

[BSA500]

I cannot feel any play in the slide but of course that doesn't mean there isn't any.I shall just tune into that low spot.