Last night i bought an 89 xr600 test drove it, ran fine but i swapped the front sprocket before i bought it cause i thought it was too low geared for the freeway. went from a 14 to a 15 and it made all the difference in the world. bought it got going home made it about halfway the engine knocked a few times and seized. im doing 65+ down the freeway in friday traffic. lucky i didnt get hit by anyone. mainly im posting this to see *** may have happened.