when i am in 1st gear and going slowit is like the engine cuts out for a second and starts again it only does it in 1st gear and i don't now what is happening please help?¿

 

Check the thumb screw on the funny looking thing on top of the carb. It easy to see if you remove the seat and pull up the rubber flap around the airbox. Mine was acting funny until I screwed it all the way in. Not exacty sure what it affects, but it did the job...no more misfiring etc...