Total Motorcycle Community Forums

'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.

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