I just bought an 81 xs400 that wasn't running. I cleaned the carbs and it does run now, it just runs like crap. It will idle well but any throttle will make the bike sputter, backfires bog down. Im assuming it's the carburetors still because the engine only has 6700 miles and looks good. I'm new to carbs can I buy new needles at the stock size and swap them out? Also I cannot find any adjustment screws on the outside of the carbs except for little pinhole plugs where they seem to be located above the carbs on other ones I've seen.
-
Enjoy XS400.com? Consider making a donation to help support the site.
XS400.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
Trying to fix an old bike
- Thread starter Riordan2
- Start date
gpounce32768
XS400 Addict
That could be a vacuum leak- make sure the diaphragms are in place and not torn, springs intact and they slide properly. Vacuum line ports on both intake boots should be plugged- usually the left one has a hose up to the fuel petcock.
Also - are the carb holders good? How about gaskets between them and the head?
They look fine. I figured out the carbs are definitely the issue. The left one was running so rich it was blasting unburnt fuel into the airbox every once in a while while the other was running lean. Going to do a full clean and rebuild on them
gpounce32768
XS400 Addict
Leaking float valves will drench a carb in fuel... When you take the bowls off note the passage which the brass tube dips into, there is a hole in the bottom of the well leading to the bottom of the bowl; that is the starting circuit. Its super easy for that to clog up.
Yep one of them had a little bit of liquid in it. Going to have to find a replacement somehow
