[markjs]

Don't ya hate it when you lose info oyou found once and can't find it again? I recently read in someone's post that they had a clogged petcock which caused the bike to go on reserve too soon but I can't find that post again. I suspect that's happened to me, unless I'm buring the whole tank in 80 miles or less? Pretty sure there is an issue?

Also kinda new here, not used to the "like" function, so if I missed a few likes early on that's why, this is a great forum!

 

[mike in idaho]

A clogged petcock won't make it run the tank empty sooner, you have some other problem. Maybe running too rich, float level off? plugged air filter? What color are the spark plugs?

 

[markjs]

I think I might have had a leak, the hose seems tight on the tank and filter but was loose as hell at the carb, so I hose clamped it, now I wait to see when I ahve to switch it to reserve when next I fill up.

 

[80cb400t]

There is actually a way that kind of makes sense on the sohc 400s/450s and that was probably my post. I'm pretty sure that the screen can get clogged enough to prevent fuel getting in and it acts like it's running out of gas. edit: see below for why.

If your tank isn't obviously rusty a leak would make more sense. Check your oil for gas as well, that would not be good. Maybe also pull the plugs and if they're completely black something weird is going on

 

[drydreamer]

Crap in the tank, rust mud, will make its way to the carbs.........rust mud will clog the filter tower in the tank and the reserve "sump" in the tap will fill with the rust mud.

 

[longdistancerider]

The petcock filter has 2 sections of screen, upper and lower. If the lower section is clogged with debris then fuel would stop early.
How much fuel have you added after the 80 or so miles?