Bah. Could've seen this coming a mile away. In an effort to fix my previous problems I decided to give the bike a good workover. Took off the carbs, cleaned the bowls, jets and air screws with carb cleaner and did a bit of other work. Now, I reassembled everything (not saying I did it correctly, but we will get to that) and tried to start the bike. It turns over, but does not want to start. Now I will run through everything I have done so far: - Choke and no choke, does not affect it. - Battery fully recharged (though it is beginning to run down again due to lots of cranking). - Oil level is good and looks clean. - Fuel is readily available (checked fuel tap), fuel is also reaching carbs as tested by draining float bowls (though I have not done this with the fuel tap on as of yet to check quality of fuel flow). - Drained float bowls, did not have any effect. - Checked airscrews and tried them in different positions, no effect. - Tried it with air filter both on and off, no effect. - Used new spark plugs (correct ones), no effect. Checked spark plug gap on both new and old ones so thats OK. - Sprayed some carb cleaner straight into carbies while cranking, no joy. - Tested compression, however I do not have a guage so I did the guesstimate method of placing thumb/finger over hole while cranking it over. Supposedly you should not be able to keep finger on the whole. While I can't say that I kept my finger on it (couldn't actually form proper seal with finger/thumb), the pressure seems fairly weak (however this is a novice's assessment; also I tested its compression before I worked on it with a guage and though, while not as high as it should be it did seem stronger than it is now). Can also feel pressure at the exhaust. - Checked for a spark on both cylinders. Now people say you should see a nice big fat spark but to my novice eyes I only got a very small one, is there a better way to tell (maybe some pictures of what it should be like? Short of some electrical testing equipment which I do not think I have). Do you think it's probably a spark or compression issue? Perhaps it might be wise to throw out some ideas (no matter how noobish, because those are probably the sorts of mistakes I would make) about what could cause poor compression and/or spark as a result of cleaning/removing the carbs and things that may have been effected near by (I didn't touch the cylinders apart from spark plugs/leads). I might go get a compression tester to get an accurate reading and might test the valves using the oil in spark plug socket test. Go on, help a noob and get +1 karma.