2stroke behavior.. normal? busted?

[esworp]

I've been massaging a 78 dt250 back to life lately (making lotsa rookie blunders along the way.. durn woodruff key!), and wanted to describe how my bike runs. I don't have any comparison to know if things are bogus or not, but things seem wrong, for lack of a better term.

The bike pulls surprisingly hard off the line with WOT. 1/4 throttle and 1/2 throttle has a nice smooth pull despite the bike's age. It will idle without complaint well below 1k on the tach at the stoplights n such.

But the thing maintains a cruising speed like CRAP. it misses and hammers something awful. Coming off a cruising speed results in a teensy stumble. It seems that it runs the roughest cruising at lower (2kish) rpms. Navigating at a slow speed through a twisty trail has it sounding really lousy. Not smooth at all.

What' the appropriate rpm to cruise at? I'm not used to this bike - while it feels smoother at 3k and higher, it just doesn't seem right to go down the street at 45 mph in 4th going BRRRRRRRRRRR!!!!oneone

 

[slodad]

2 strokes tend not to cruise smoothly if they're not under a load. At the low engine speeds you're describing, there's not enough wind resistance to put a load on the engine. Try riding up an incline in a higher gear to see if it becomes smoother. It sounds to me like your bike is behaving normally.