Motorcycle Repair: 2nd gear top end boging and seems to missfire, golden spectro, straight dirt

Question
as I rode yesterday......I climbed the same hill as last week in the same manner.....although this time as I rode up the hill at the top end of 2nd gear the bike seemed to loose a little power and bog down...with a pop or miss fire ...So I took the bike on a straight dirt road and opened it up running thru the gears and the bike seemed as quick and powerful as normal....this is a 97 KDX 220R.
top end never touched and I usually clean the air filter after every ride...this is the first time this has ever happened...
I did change the two stroke oil...I was using Golden Spectro..but bought Kawasaki two stroke oil....I used one bottle to 5 gals gas.....
I did notice that starting the bike since I changed two stroke oil has been somewhat different....had to kick over many more times...then it would smoke like a bandit...then usually after 5 min the bike would be warm enough to ride and not bog down. This time 15 mins into the ride and as I would hit the throttle it would still bog down....
could this be a improper oil mixture that has fouled my plug ?? and would that only affect the top end of 2nd as I am climbing and not affect it on the straight flat dirt road ?

Answer
Hi Mark,
Although this isnt my strongest area, it alwost sounds to me like the float maybe had let too much fuel in flooding it out as you climbe the hill. Is there a chance the front end was higher this time from last? I know when i try to start a bike thats been sitting for a while is lock the front brake  (sitting still) and rock the bike violently so that the fuel spills over in a way (flooding the carb) so that it gets a more rich mixture on cold start. Sounds like this might just be the case. the other thing i wanted to point out was sometimes when this occurs and there is unburnt fuel, it'll fall into the crankcase also acting like its flooding out..there should be a plug at the bottom of the case where this can be drained out in a 2 stroke. Give those a try, hopefully it'll do some good for you..

Hope this helps!

~Mark