Tuning Attempt one

15th Feb 2006

I decided that after fitting the new spark plugs I would have another attempt at tuning up the engine. The baseline setting I had for the mixture screws were 2 turns out from bottomed. Before I ventured to the car I spent some time reading on the Internet I looked at the Redline Weber web site :http://www.redlineweber.com/html/Tech/idf_adjustment_controls.htm and saw that the mixture screws here for baseline were one turn out, this was a lot more than my previous article had stated. I decided to look further and found an excellent article on jetting, and synchronising: http://www.aircooled.net/gnrlsite/resource/articles.htm . The air cooled website had some very useful information abed out jetting which contradicted the print-out that I had about jetting. It suggest that my main jet should be smaller a 50 idle jet , were I had a 55. It also suggested my main jet should be 1.17 were it was 1.30, my Emulsion tubes were correct . The article went on to say that the spitting and spluttering that I was seeing ad high revs was due to the main jet being to lean and needing to be go bigger. My Air corrector was set to 2.00 and the crackling exhaust noises could also be attributed to the the jet being to lean and it suggests a 1.80 jet.

This all sounded interesting reading and to be honest was something I was going to have to look into further obviously the Redline jetting was a guide and not a completed solution. I would have to find out were I could buy main, idle and Air corrector jets to try this and this was going to have to be picked up another day.

I got out to the garage and decided to ensure that my idle was set OK and that the linkage kit was well balanced I started by looking at the down adjusters that adjust the position and balance of the linkage kit. The left arm did not have much track on it for adjustment. I decide to remove the ball joints and run the car without the linkage kit. This enabled me to set the carburetor idle screws up for each carb to try to balance them out. I had read somewhere that using a 1/2 tube across the top of each ram tube would enable you to hear the difference between the carburetter pulling on each side. The interesting thing was that you could hear the tappets drumming too.

I shortened the left adjuster taking care to thread the correct end. This is important as only one of the threads can be thread with conventional taps and dies as the other is a left hand thread. Threading down the wrong end with the idea of then shortening it would severely brake the adjuster. I checked and checked again the end threaded it with a 5mm die further down replaced the nut and then cut the end off the rod. This fitted beautifully and allowed a lot more movement for adjustment. The afternoon was going well I warmed up the engine and set the mixture screws up at 1 1/2 turns out. The car was starting to run better. I still had the pops and crackles at hi revs and believed i needed some more information. I would contact Air Cooled and see if they would make a recommendation differant to what I learnt from their site.