1980 xs400 special II won't start... Help!

[unitedhow]

Hello again,

I'll start by saying thanks everyone for helping me so far the advice here is sooo helpful.

Now the problem is. My bike won't start.
I have checked spark. (Plugs are old spark looks good though)
I have just rebuilt the carbs. (New gaskets,New jets air screwed out 1 1/4 turn, floats (set to 32mm as per the manual posted in the tech section of this site)
I have clear gas line going from the tank can see the gas going into the carbs, I forgot to tighten the float bowl nut all the way so I saw a drop from there on both sides before I tightened them.
New carb boots.
New air filters.
New battery.
And compression over 120 within a psi or two of each other on both sides.


Tried kicking it... Nothing
Tried electric start... Cranks but doesn't start.

What could be the problem?
If it had to do with the carbs wouldn't it start but run poorly?
Tried a small squirt of starter fluid in the spark plug holes but nothing.

Thanks for your input!

 

[willem]

Try starter fluid into the hole of the air filter (take it out for a second)

If that doesn't help, you're missing your spark. Sometimes it will spark outside of the bike, but not under pressure. Change the plugs, caps and wires, charge the battery (sometimes it has enough juice to crank, but not spark) and report back.

If starter fluid helps, it's your carbs. Check your float height, make sure your carbs are getting fuel (check petcock, kinks in fuel line etc) and use a little choke.

 

[unitedhow]

Ok I will try that with the fluid. Do I spray it into the intake hole of the air filter case with the filter in and still attached? Or do I remove the air filters and then spray it in where they would connect? (I'd hate to ruin brand new air filters) and replace the plugs and wires. I have been looking for answers and have seen that people say 26mm for the floats (brass floats 1980 xs400 special II b34s) is that right? or is it 32mm like the manual in the tech section says (the manual that is for older bikes but says it should cover all sohc engines)

​

 

[willem]

it's better to remove the air filter and spray it directly into the air intake. At least change the plugs, and check the caps and wires for corrosion. If you're unsure about them as well, replace them.

the float height I'm not sure about, I think I also read some different values on the forum yea. The manual isn't always right, especially when setting up the fuel mixture so it wouldn't surprise me if the float height isn't exactly correct.

anyone else know?

 

[unitedhow]

Changed the spark plugs and it still didn't start. Adjusted the float height and success! I read 26mm and 28mm so I did 27mm and it sounds great! Thanks willem for your help. The starter fluid suggestion helped out.

So I'm going to say here that if you have a 1980 special II with brass floats the correct float height is 26-28mm

 

[willem]

awesome! good to hear its up and running. Now get some miles on it, quick!