Project bike just won't start

[MrShake]

Hello folks!

I 've got an 82 Yamaha Maxim XS400J.

I bought it not running, so its deffinatly a project. I've spent the last 2 weeks cleaning carbs and replacing parts (gaskets and stripped screws) and just got the carbs back together today. I got the carbs back on the bike. Checked, I have spark and did a quick compression test and I have compression. But still no starting.

I did notice that there is gas getting to the air box or dripping out of the back of the carb if the air box is not connected. I also pulled the plugs after trying to start it and they are went and dark. I assume this means the bike is running rich. Would that cause it to not start at all?

If it is running rich.. any sugestions on how to fix it? I'm suspecting possibly the floats, but I'm not sure how to adjust them correctly and my manual is not here yet.

Any sugestions would be great!!

[< I Fly >]

So does it turn over then?

I am assuming the starter turns the motor over but the engine doesn't actually start running.

If so, and especially if your plugs are wet, you are certainly running rich.
First thing to do is check your air filter.
A clogged filter will not let in enough air, producing a rich condition, possibly enough to flood the cylinders at which point you're definitely not going to be starting it.

Assuming that's fine, check the vacuum line coming out of your petcock as this was causing me some problems just this week (although it did actually start ok).

Another possibility is to check and see if the ignition is working right.
Good airflow, plugs, and carboration won't do craap unless you actually have electricity.
Test to see if the spark plugs are firing.

[MrShake]

Yes, the engine is turning over and the starter is fine. Both plugs do have spark. I've tried with and without the air filter and still no joy.

[< I Fly >]

How much do you screw around with the throttle and choke while starting it?

Not that you should have to, but sometimes that can get a recalcitrant engine to start humming.

[MrShake]

I've played with both quite a bit. Today I also checked the float bowl level with some clear tubing and its comming to just under the gasket level, so I know its not overflowing into the venturi.

still not sure what to do next.

[CORSCO]

If fuel is getting into the airbox, your carb needles are leaking. Check for debri between needle and seat, then check very tip of needle, should be perfect triangle, then check the seat for wear marks at sealing area.

Or just buy new ones.

[MrShake]

Update:

I've done some more troubleshooting and heres what I found:

Put carb cleaner in the carbs while turning it over and no bang, I also tried a bit right in the cylinder and no bang. I pulled the plug and grounded it to check spark again and noticed that the spark looks a little weak and yellow.

I'm thinking the next step is new plugs and wires. I am also concerned that perhaps the timing is not right (sugestion of my father), but I believe its not adjustable on this bike. Does any of this sound right?

[Stratus311]

On an 82 Maxim, you shouldn't have to worry too much about timing. If the spark is weak, check all the wires to the coils for shorts, lose connections, etc. When your manual gets there, check the specs on the coils like resistance, etc. I'm thinking definitely ignition, and still possibly carb issues.

[MrShake]

Heres a question.

I'm looking at replacing the plugs and wires before the ignition coils.

1. Are there aftermarket wires for these bikes?
2. Will universal kits work?
3. Is there a way to test the wires before replacing.

I also noticed that the caps and wires are seperate pats. I assume both need to be replaced (almost 70 bucks for a full set) but if thats not the case then can I just do the wires?