i owned a 250dx in 1976 seven of my friends had one each also, seven blue and one silver, they were all six speed, there was a change in these models from the previous model, more torque but not able to rev out as high, they hit 7-8000 rpm and needed to be changed up i previously had a RD 200B, my friend got a 200DX it was the same, torqey but slower top end, the 200B held 3rd gear for a long time as it accelerated, i was humbled on my 250dx by a suzuki 250A but top end only i lost him on the bends! it goes without saying that eight 17 year olds on identical bikes tend to ignore speed limits i can still remember the sound of 16 cyclinders lighting up at the traffic lights it was like a swarm of bees, 76 was a hot summer and a barrel of fun for rd 250 dx riders in northern ireland like me and my buddies