Firing on one cylinder, wont stay running

[jacjr]

Whats up guys, my 80 xs400 is firing on one cylinder,its hard as all h*ll to get it to start and then doesnt like to stay running at all, my dad says its most likely the carb but i dont know where to start my money is tight so a rebuild kit is kind of out of the question right now i was just wondering if there was something that could be wrong that could be fixed with out really spending money, but all answers are welcome!!

thanks bros, John

 

[XSLeo]

If you carefully tear down your carbs and clean them you won't need rebuild kits. Most kits are a generic kit that seldom has the right parts for your application.
Once you tear the carb down and are cleaning it inspect the parts, only replace the parts that need replacing.
This carb guide is for the XS650 carbs but the XS400 uses a very similar BS34 carb. The specs for adjustments can be found in your repair manual.
www.amckayltd.com/carbguide.pdf
Leo

 

[Liamthedevastator]

Have you replaced the spark plugs recently? I had a misfiring piston on my '04 gsxr and changing the plugs fixed it (at least for now...) so maybe that could help if you need something cheap n' easy to try first? It'll be $20

 

[arfstrom]

My bet has been on Stale connections on your plug wires. I have had luck recommending, and cheap too trim 1/2 inch off either side of your plug wire, both sides. then when you reseat the wire into the coil and the plug cap, it will be fresh wire connection to the old connecting points. and when you can get the $$ for it, you can get the plugs, the ones recommended in my signature are close to USD 2.50, and then caps and new wires should not be too much.

But the other side of the issue is the Carbs. So my recommendation is cheap up front, and then if the bike is still only one side, then work the carb issue. (lots a cleaning threads here)