Originally Posted by 65bmwr50
I can get it to idle nice and smooth. When I try to increase the throttle on it it will stumble and cough and then it will start to rev. At that point it will rev fairly easily and smoothly. Now when I let the clutch out it will start rolling then it just dies. I pull in the clutch and goose it and it is back to coughing and popping. I also need to add that I have done nothing when it comes to timing or tuning the carbs so far.
Nothing is good, and how it should be. Adjustments should be made one at a time. Take it for a ride, and then make another one. If you try adjusting 8 things at once, you'll never figure out which part is screwin' up the works. Don't ask me how I know this!
Let's start by determining that your throttle cables are connected, and connected correctly. It's possible that you're not lifting a carb slide. Maybe late, maybe not at all...it would start and idle, but cough and die under load. Which is what you described.
Pull the intake tubes off. Check to see that the slides in the carbs are both lifting at the same time, when you twist ze throttle.
Set two swizzle sticks, [mini tongue depressors] under each slide. Gently engage the throttle, the 2 sticks should start moving at the same time. There's an adjustment if they don't.
Make sure the slides are returning to their bottom position as well...
These bikes are well made and dead simple. If something ain't right, there are only a few things that can go wrong. Start with the obvious.