How to measure carb floats on XS-400

[Juelze]

Hi there,

My brother recently bought an 81 XS-400 and it was having starting problems. We took apart the carbs and found the issue. One of the floats was stuck. We got it cleaned up but were curious on how to measure the distance on the floats form the carb flange. Do we hold the carbs vertically or upside down?? We measured them upside down and I think that's wrong because it seems to be running lean. ALso, I think the float is still gummed up because the first few times we tried starting it fuel spewed out the rightside airbox. Also, he's having issues with the battery staying charged. Any ideas?

I greatly appreciate all your advice!

-Ryan

[Stratus311]

To check the float height, hold the carb upside down, and measure from the gasket surface(for the float bowl) to the top of the float. It should be anywhere between 28 and 36mm I think. The lower the float sits in this position, the richer it will be. ie: 28mm height would be richer than 36mm height.

As far as the battery goes, depending on how old it is, it may need to be replaced. Old batteries don't like to hold a charge. Try putting it on a trickle charger over night and see if that helps.

[Juelze]

Hi again,

Okay, we did measure the floats upside down so we should be safe there but it seems to run a little lean yet as it sputters but once the choke is out a bit it run smooths.

The battery in the bike is brand new, just got it a few days ago. Any other ideas?

Thanks for your help!

[Stratus311]

With the bike running, spray some contact cleaner or WD-40 around the carb boots and the gasket area and make sure there are no air leaks. The idle will pick up if so. Then proceed to adjust the fuel mixture if need be. Also, have you cleaned the carbs yet? Mine was running lean until I gave them a good cleaning. Now it's great. Another thing you can try is setting the floats a little higher(with the carbs upside down, the measurement gets smaller) and see if that richens things up a bit. Do it in small increments though.