120 seems low for a 2 stroke. Should be in the 175+ range. To check timing you need to check the mark on the stator against the mark on the case. Kind of hard to get to without pulling fly wheel (havent dealt witha 98 rm specifically just in general). Did you try and pop start it? Seems like a low compression issue to me or a plugged pilot jet in the carb.

pulled everything apart pistons in with arrow pointing to exhaust, timings marks are dead on and spark is blue, also checked carb everything seems ok but it wont start im so puzzled, also did compression retest with throttle wide open and got 171 psi. also i cant pop start because my chain is mia and had to order new one. thanks for helping i do appreciate it

Make sure the reed block is not warped b/c it could let air in where it meets the cylinder. You definitely see spark at the plug? If so, that rules out a bad kill button. Did the head and base gaskets get installed? I know you said it it getting fuel, is that because the plug is wet?

Crank seals are a good thought. If they look good, and you have compression, spark and fuel, it is most likely your cdi box/ignition module. This controls your timing curve and if it goes haywire will cause it to not start because your timing is off. The stator controls your static timing, but if the box is bad it will also cause your timing to be off.

Doug