The ETZ range mid 1980s?? onward was 125 and 250, the original 300 (299cc) being a UK special by the importer Wilf Green, these were noted for their not inconsiderable thirst. After a few years the 250 was discontinued and the 251 (same motor different barrel porting) was introduced. These had very similar styling to the 125s which continued throughout; smaller shorter and lighter. At the same time they produced the 301 which is a model designation as the motor is smaller that the 300 but only by 5cc iirc. This motor had that extra something but was not as thirsty as the 300 because of port changes.The later you get the poorer the finish until they eventually were going to get rid of the 2Ts altogether but public outcry resulted in them flogging the machining to the Turks who manufactured them with some minor and some not so minor changes; to my knowledge this lineage is now dead even in Turkey. My personal preference is for an ETZ250 with a 301 engine, with this you get the better quality parts, more stable handling 18"F&R and more of a big bike feel, the 301 engine provides a bit more zoom in the midrange and on hills.
The predeccessor of the ETZ was the TS series. 125, 175, 250 all four speeds and the 250/1 which was a five speed. Many would claim that the 250/1 was the best engine ever, others the ETZ301, I have never had a TS so cannot comment.
If you do get one, try to ignore all the bollocks about cruising at 80mph. They will go very nicely and I know Jethro has had some quick ones but common sense dictates that if you flog them too hard then you will get problems. Even the autolubed ones are not as slick as the Japanese bikes oiling systems. I would also recommend that you get the MZ-B ignition which is plug and play and requires no TDC static or dynamic timing but does unleash revs galour.
well I hope that covers it, they are not getting any cheaper and parts are not as available as they once were, but not a dire problem yet.
Steffan