sorry, I have to warn you guys again about the torch tip cleaner. It will change the orfice size of any of the holes you run it thru. WE had a Yamaha engine that was runing rough under load, everything checked out when we took the carbs apart. On the dyno, its was "fourstroking" trying to hit every other time under load, indicating a rich condition. We took the carbs apart and checked the jet size against teh book,it had the correct jets. It wasn't untill we found out the owner had receently rebuilt the carbs himself did we start a closer inspection. We compared the jets in his carb against another set of the same size and discovered his welding tip "cleaner trick" had opened up the main jets by a clear margin( you could easily see the difference without any visual aid). We repalced the jets with new ones from Yamaha, and the engine ran perfect. Welding tip cleaners are made to remove metal, I use them to open up air bleeds on Q Jet carbs(allways mike the reamer to make sure its the correct size). If you can't get the jets clean with cleaner(or teh sonic cleaner), then they are usually pitted and will need replacement as teh pits will affect fuel flow. If you happen to alter the jet size on purpose, remember to polish the jet openings to remove the swirl cutting marks left by a drill or ream as it will affect fuel flow as well. We use a tooth pickcovered with lapping compound in a biderectional drill, work it just like lapping valves
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