1ST gens are nothing but issues by now. There are 3 main things with them and most do not know how to fix any.
#1 kicker gears...i do have a fix but i had doing it. Its a 2 hour ordeal to back cut the gears and shim correctly if you send to me.
#2 the axle sprocket hub assembly's are always worn down and loose, it was a stupid design again. I have a 300ex axle fix but that requires being able to weld. I can make weld on sleeves and the rest if up to you.
#3 is the rear brake assembly on the motor...dumbest thing ever. I have come up with a fix but a custom foot lever needs made and it can get costly if you cant think weld and machine.
I own a 86 trx200sx which is the semi auto motor copy of the 2nd gen 200x. I will say everything about that motor up top is SOOOO much nicer and easier. You can adjust the valves with out a freaking feeler gauge too! It was a great motor. Yes there are some hard to get
parts but the top ends are 100% the same as trx200sx atvs so jusy buy as many 500 junkers as you can find when building a 2nd gen 200x. I'd never waste my time on a 1st gen 200x again. Ive don't it too many times.
There is 1 issue with 2nd gen 200x...metal tanks only and do not be supersized if you spend $1000 to get one redone. If you cant an aluminum one HREatv.com will make you one and i'd rather see aluminum used then steel when its related to fuel system.
Either way be warned, these things are 40 years old and everything is wasted and worn out on them by now. Every time I build a trike I buy 3 or 4 junkers to build 1.
I have a newer machine from 2007 and its stupid how easy I can get new replacement
parts vs a 40year old machine.