1987 and 2009 TW200's
Might try putting a new spark plug in and taking a plug reading to check your fueling.It’s not bad off-road as long as I keep the revs up. I’ve done some pretty gnarly steep rocky jeep roads with it already.
I run a 15 X 44 sprocket combo in my '87, I am 6'-2, 175#.
Works well in most situations (NOT tight technical stuff)