Dirtbike question-gear related

[glockrod]

I have a '05 Kawasaki KLX 300. I bought it used about a year ago, and it looked barely ridden. I have probably put 100 miles on it since purchase all of which on trails/dirt roads. I rode it for a couple of hours this weekend, and noticed the gears changed kinda "hard" in the lower, more used gears(1-3 of the 6). What I mean by hard is that they didnt seem to mesh smoothly at times.

I really didnt think much of it, but a buddy just bought a new Kaw 250 Dual sport. I tried his out, and the gears were much smoother.

I dont, nor have ever rode street bikes, and before buying this bike, I hadnt rode since being a kid. Does it sound like something to be concerned about, or is relatively stiff gears typical for dirt bikes? Is there something I need to check or adjust?

Thanks
Rod

[TenMillimeter]

Has the oil been changed in the last 300-500 miles, and is it the proper oil for the bike?

I've had bikes that were hard to shift when the above weren't followed.

[glockrod]

Oil changed probably 40-50 miles ago. Was late last year when I did the service. The oil filter was a real bugger to replace. Oil level is fine.