hi, about a year ago i bought my brother a used trx90(2001). this engine needs replacing bad now. the sparkplug threads are gone, electical is a mess, and it just stop running all of a sudden. I just cant find a replacement motor for it. Does anyone know a website that carries this motor. Is there any other motors that will fit in this bike. thanks in advance.

 

lifan makes engines for it i just put one on mine. but the engine i got was a 138cc. with a clutch an it was 1 down an 3 up it was like $400 but you can find them on ebay. an you can use the stock carb an exhaust

 

You should be able to buy a create engine from Honda and/or any parts you need to get it back running.