according to haynes early dtrs (89) and tzrs had the same round sode carb but main jet on tzr was 180 an dtr was 125 cos my bike came in bits with tzr spares included i had no way of knowing if carb was off an early dtr or a tzr as it was round side carb, initially i tried a 200 hoping it was a tzr carb but if not atleast i hadnt gone the other way and left bike really lean, but was having a slight spluttering on top end when bike been running a bit so figured it may have been an older dtr carb with a 125 main jet and 125 to 200 was bit o much of an increase so ive ordered a 125 cos thats what haynes says is standard and a 150 cos thats a slight increase and just see how i fair with them, plug is brand new and after half hour when it started to splutteri took it out to check and it was a little oily but as am currently on premix it might be why plug is a little oily its not really bad, ill know more when i change jet and take it out again hopefully tomorrow. ive been running it premix been experimenting between 30:1 and 40:1 cos didnt have an oil pump but ive got one now ill fit it later this week just concerned about fitting a 2nd hand pump in case it aint 100% and makes more problems than it fixes, as for cleaning the air filter it looks like its seen better days and no idea how old it is bits of foam are falling off it so for sake of a tenna off ebay may aswell just replace it. ill let you know how i go once postmans been cheers
yeah it is the round side carb but what i ment was older dtrs had exactly same round side carb as tzrs just different size main jet thats why ordered the standard spec jet and a slightly larger one, but cheers tho