'79 looks good but doesn't run right

[79rootbeer]

Helping a friend get the '79 xs400 running right before I officially buy it. Swapped in a new battery, fresh fuel and oil, but it still won't run right. It revved up really good with the new battery and all, but finally bogged down and died. Every start after that sounded weak, even with the throttle wide open. It hits 1k, maybe 1.5k on the tach but then dies. Pulled the carb apart and the jets are 2 different sizes, but the needles aren't. A nice groove was worn in on the smaller one. Ordered new ones. Any idea what else could be wrong?

 

[HoughMade]

My guess....as usual....dirty carbs.

One of this forum's T-shirts is dedicated to this diagnosis:

Cleaning the carbs well is a meticulous process. Skip a step at your own peril:

http://www.xs400.com/forum/showpost.php?p=64401&postcount=17

 

[79rootbeer]

Thank you sir. I have spent a couple hours looking for that.

 

[79rootbeer]

Here's what she looks like now. Plan on doing a few mods once it's running right.

 

[HoughMade]

Not bad at all. Did you mod the seat to take out the slight step?

Here's my '79....mostly, but not all, stock:

 

[79rootbeer]

Most of what you see was done by the PO, my friend. Judging from the underside of the seat pan, it looks to be modded that way.

 

[79rootbeer]

Well, after having a buddy of mine check out the carbs, we figured out that they're the wrong ones. Guess that means the PO bought the wrong ones, or they were advertised as the wrong ones. Either way after fixing them and getting them running about as right as they can, it still doesn't run quite right. Found the old carbs and am in the process of cleaning and rebuilding them. Should be ok. Now with the starter, it either is junk or they never really worked right to begin with. Other than that she runs and is almost done.