Bought a 1982 xs400s cant get it running need help

[smurf_x400s]

Hello, im new to this fourum so please bare with me. I bought a 1982 yamaha xs400s and i cant get it running, it sat for years so i cleaned out the carb and the gas tank, all of that is fine. it gets compression and cranks but does not start. i need some advice

 

[HoughMade]

Does it get spark? Take a plug, attach the cap, and lay it against the head. If it sparks, you still have fuel issues. If it doesn't there;s the problem.

If it sparks, it the petcock set to prime? Try taking a air filter off and spraying starting fluid or carb cleaner while cranking, if it fires- again, fuel supply is the problem. You would not believe how clean these carbs have to be to work well. Every little internal passage must be clean.

 

[volcomskater77]

im in the chicago area. where are you located? mine isnt running yet either. but it never was before i started my build. so ill be in the same boat as you in a week or so

 

[smurf_x400s]

ya my buddy tried that while i was at work...im gonna try that agian...also the wires are from 1982 lol so maybe there junk you think??...and tested the coils theyre good...and petcock was on prime and i left it on open by accident another day and flooded the carb..do you think its maybe plugs or wires?? and im located in harwood heights, il its a suburb next to chicago

 

[lhaolpa]

ya my buddy tried that while i was at work...im gonna try that agian...also the wires are from 1982 lol so maybe there junk you think??...and tested the coils theyre good...and petcock was on prime and i left it on open by accident another day and flooded the carb..do you think its maybe plugs or wires?? and im located in harwood heights, il its a suburb next to chicago

You'd better check your oil to see if it smells like gas if you left the fuel on.If the float needles don't turn off the gas,the gas can flood into the crankcase and into the oil,then there go your bearings,and if it starts,it could blow up! lha

 

[Under Dog]

I see you cleaned the tank and carbs, but here's a thought. Did you clean out the petcock and fuel lines? They will gunk up too and it's possible if you put "clean" fuel into the tank it just pushed gunk from the petcock and fuel line back into the carb and clogged it up again...

 

[HoughMade]

Before you go buying or switching parts- do you know that lack of spark is the problem? Changing parts should be a last ditch method to diagnose. 99.947% of the time, you should have a diagnosis before you start buying parts.