yes, i think it will even fit on a ttr 90.
Most likely, if the 1998 is a 250 also
only if you are jesus and you plan on working a miricle
No a 125 frame is too small to fit a 250 motor but with a cutting torch and a welder anything is possible.
it probably wont line up correctly with the top end
No. According to the FMF website, the 99 and 04 YZ125 have different part numbers.
yes
Very unlikely. Check with your local Yamaha shop.
Yes it will all yz125"s are the same from 96-2001 hope this helps :)
Even if they are the same year models, I highly doubt it. Best thing is to check with your local Yamaha shop, they would be the best ones to answer this specific question.
125 or 250 if you fit on the but but they run together in the 250 class
what year models can i use parts from to fix my 1992 YZ250
No, the plastics for a Yamaha YZ80 will not fit on a Yamaha TTR125. These two bikes have different body styles and dimensions, so the plastics are not interchangeable between them.