craig70240

Ah the joys of SU's.I have an early 240 {HS30000219}and recall having problems tuning them initially after the car had sat for a long time from previous owner.I did have access to a tuneup machine though.The problem we had was if you set the CO reading as recommended,the car would idle fairly well but as soon as you put any real load on it i.e. drive around a corner and up a hill, it would bog down and labour and almost stall.A friend that was helping me,a mechanic with years of experience tuning british su's on triumph's etc was at a loss. We then found an expert who'd had the same problem recently and he said to set the mixture up at about 1750RPM.this was the trick and the car ran perfectly.A simple check to see if you have a vacuum leak around the throttle shafts is to spray carby cleaner at the throttle bushes and see if the car bogs or the revs drop noticeably, do this at idle.If it doesn't bog down, you don't have a problem.Do not use different needles in the carburettors,set them both at exactly the same spot in the pistons.Checking the sparkplugs is also a real easy way to check the tune of the engine especially if you don't have access to a tuneup machine.I hope this helps. regards Craig.