SU Carb needles

[gripper]

I've just stripped my IP2 carbs in an effort to cure poor running when cold (even after the retard has kicked in) My carb needles are stamped 51XA yet the manual says they should be ADR. Any Ideas as to if these are wrong or an early designation? The tickover and general running are fine after about 5 miles but until then it's like riding a pogo stick, gradually improving until fully warm. I've replaced coils, ignition (digital now) plug leads, plug caps, plugs. Maybe the old Sparkrite box was ok. At least I've got Carlos Fandango digital ignition now. I seem to recall reading about different needles in some old Epitrochoids but they are hiding at the moment so I can't refer to them.

[Richard Negus]

I believe that 51XA is correct for both IP2 (twin rotor idle) and Commander, and that AEF is an equivalent 'production' reference from SU.Although I haven't got a Manual here, I think ADR is for single-rotor idle only.Andover have (or had) AEF needles under part number 55-0818.

[ZFD]

According to the stock list Andover Norton have them in stock.Joe

[johnbirchjar]

I have the same problem with Classic,I just run the old girl with the choke out about 1/2 an inch(or a clothes peg width) untill the temp; guage reads over 100c then just push the choke fully home(removing said peg of corse)I,ve used this method of cold running for many thousands of miles.Readers of this forum will be well aware of the problems I,ve had with hot running,(almost 150c on a bad day)well, removing the cover plates at the rear of the cylinders has made quite a differance, running up to Stamford Hall & back the old girl never went above 110c,mind you, it was not the warmest of days,but still a vast improvement,ride safe,regards,J.B.

[gripper]

Thanks for that John, I don't tend to leave the choke on for very long at all. I've just obtained some viton tipped float needles from Burlen fuel systems on Richard's recommendation.(quite cheap) I've also made up a setting tool to take a dial test indicator and set the needle jets but I don't think they were far out using my digital vernier. I'm sure the cover plates trap air behind the engine. Another benefit of removing them is that you can quickly access the temp switch and the vacuum fuel tap pipe. The rubber adaptors for the vacuum pipe don't seem to be able to deal with the heat in that area very well. I might solder a longer copper pipe onto the fitting (from an oil pressure gauge) to reduce the length of flexible pipe and take the rubber adaptor away from the heat source. Any thoughts?