It finally Runs kinda

[ScottS]

Ok i have a mutt xs. Diff head, diffmotor, and some of the 79 carbs. The bike runs. But here is my problem. The bike will only run with the choke on. And it will only idle about 4000 rpm. We got to hit the throttle and it cuts out and dies. The plugs show way to rich. We have adjusted the mixture screws to as lean an possible. Tried playing with the timeing. The only way we can get the bike to rev up is physically choke the amount of air going in the carbs. Does anyone have any idea's as to why i can't seem to get this bike lined out? Everything has been cleaned up and all electrical has been cleaned. The carbs have been cleaned and adjust off the bike atleast 5 times.

Scott Stoner

[skids]

It is either the pilot circuits of the carbs OR the pickup coil wire problem.

[skids]

Well, OK, it could be other things...I just don't know what!

Originally posted by skids
It is either the pilot circuits of the carbs OR the pickup coil wire problem.

[RiskyBusiness]

Scott, have you done a total inspection and clean job on the carbs? Having done that (twice) I know that a multitude of issues can be traced to dirty carbs that need inspection. Trying to fix the symptoms of a carb that needs cleaning and rebuilding is a lot like trying to fix a gun shot wound with tylenol. After you are sure the carbs are totally clean and all the jets open be SURE and balance the carbs. When inside the carbs you may find other surprises.

[Ken Talbot]

Among other things, it looks like you've got '79 carbs which require the float bowls to be vented via vacuum hoses located between #1-#2 and #3-#4 ( connected to the upper "T"s, not the lower ones). These hoses should connect to the nipples on the upper half of the airbox. However, the nipples on your '81 airbox were not drilled because the '81 carb floatbowls vent a different way. Drill out the nipples so your floatbowls can breathe and you will be one step closer...

[prometheus578]

A bike that will only run with the choke on means it's not getting enough fuel. Fouled plugs mean you're getting too much fuel. Carbs are plugged, or way out of adjustment.
Now... are all cylinders acting up? And if so, why? Have you done a compression check yet? Pull all the plugs, hold the throttle wide open, and check each cylinder.
I've seen a lot of bikes that have had real loopy compression readings, where the owner's have tried to compensate by fiddlin' with the carbs. Check compression first.