starting Hassles xs400

[kar_the_terrible]

'78 Yam xs400

My bike wont start <sob>. I just cleaned the carbs, made a make shift fuel tank out of a coke can and a supply line (works well), and ran the starter. No soap. I did the following things:

1) I thought the battery might be weak, so I took out the battery out of my car and used it to jump start.
2) I checked the plugs, I get a decent spark (Not a fat blue spark), but I think this spark *should* ignite the mixture.
3) Checked the carb floal bowl drain plug, bowls have fuel in them. When I remove the plugs and run the starter, I feel the blast of air from the cylinders, so im getting compression.
4) Gave it the choke and tried again, but no.

Now why wont she start? Is this a complete checklist:
1) Check timing again.
2) Get new plugs (if the old plugs fire, isnt that sufficient to at least ignite the mix? I know new plugs give good performance.... but still
3) What else must I check again. The carbs are extremely clean I just sprayed them down with carb cleaner and put in new gaskets.

[skate13420]

check to see if your clutch is engaging slightly. Put your bike up on its centerstand and put it in neutral. Kick it over a few times and watch the back tire to see if it spins a little bit. If it does, you need to adjust the tension in your clutch wire. I had a similar problem with my 81 xs400 and this seemed to fix it