Low rev. missing mid range rattle..other issues.

[J-ROCK]

When I'm off or just slightly on the throttle in gear costing (1/8 turn or less) my bike stutters and misses apply just a little throttle and it seems fine. When going up in revs a get a rattle sound almost sounds external but it's most definatley not. it's an odd accurance.
The plug seems fine, although reading Gorr's tech pages I notice that I have only really "Read" the plug on the main jet I will check it after putting around tonight.
Another possible related issue..
every once in awhile I get a slight kick back.. or hard kick.. sometimes a get a slight backfire more of a fart.. It's almost like the timing is out but I'm as newb and from what I've read the timing is controlled by the CDI with is non adjustable and either goes completely or works as it should..
Bike is a 1995 Yamaha DT-200 Canadian model.
fresh top end and otherwise stock.

Any help is appreciated!
Thanks, JROCK

 

[souphmars]

my bike use to fart to-it hasn't farted since i changed premix oil-it sounded like a sneeze to me-for the rattle, could ur pipe be loose, b/c mine is a little loose, and i can hear it ratttle a little bit when i rev it up real good

 

[J-ROCK]

All I have to say is... DAMMMMMMMMN. I just went over all the relevant info on Eric Gorr's site and that guy rawks! wicked site.. a must read for any two stroke owner.. but y'all knew that already ;)