Ok, so my Mini is running since the rebuild. All is fine, it starts and stops BUT when it is taken for a drive and you have to stop at an intersection or traffic lights it idles but at about 500 rpm higher than idle. Checked the twin SU's but have no idea how to fix. Any ideas of what needs looking at?

BTW I have new needles and jets damper springs and using correct SU damper oil.

I would suggest getting it tuned professionally. You have done the basics of getting it running, now look after the rebuild by getting the correct mixture in it.
It could have vacuum leaks, butterfly linkage issues, insufficient damper oil, oval jets.
Good luck with it

_________________
1963 Morris 850 Smoke Grey
1963 Morris 850 Shadow Blue
1965 Morris Mini Smooth Van
1966 Morris Mini Van
1969 Morris Mini Deluxe Resto
5/72 Clubman Gt

A quick check is to ensure the inner cable isn't getting hung up on the outer sheath at both ends . Ie at the foot pedal ( a good idea to look anyway and squeeze the 'forks together) and also at carb end - look carefully at linkage kit, trunnion , and or swivel barrel . Most likely is linkage kit when it goes overcentre ( on full accel). See if you can replicate it without the cable connected to isolate.

Yeah, give the linkage a wiggle when it's doing it, you'll find something getting hung up

But maybe it's just excited and saying "That was fun! Let's go again!! Yaaayyy!!

_________________
did I tell you that I won a trophy?

Assume you adjusted idle when engine temperature was warm? Also check the positioning of your "fast idle cam" as this - whilst actuated with choke - can maintain a high idle when your choke is not in use, i.e. after the engine has reached an operating temperature and the choke is no longer required, the adjustment screw against the fast idle cam can produce this symptom.

Hinesy1275 All adjustments made when car is upto temperature in the garage.

It only happens during a run of several miles, never when started cold overnight and brought up to temperature in the garage, say 10 to 15 minutes.