Here is the deal, bought an 85 trx 125 cheap,had a sticking valve, after some blaster + marvel mystery oil valve unstuck, still low compression. took the head off, valve seems to be seating, but I'm thinking it is damaged (intake valve). I was going to do a valve job, but saw a used head on ebay. Can I just swap heads, or do these parts have to be broken in together. Also if I decide to rebuild mine, can I just install new valves, springs, and keepers, and then do a short break in, or do I need to grind on the new valves. I'm a newb any help/advice would be greatly appreciated. Thanks

 

any time i've redone a head i've always done atleast a three angle valve job. i personally wouldn't assemble a head without making sure my valves seat good. to make sure install the plug and valves with springs and fill the combustion camber with water. if it leaks it needs a valve job. also you can mark the valve face with chalk and spin the vavle slightly in the seat. if you see the chalk marks have a break in them then it is seated properly. if you don't want to pay a machine shop to do the valve job you can purchase valve lapping compound at just about any auto parts store. its pretty cheap and fairly easy to use. hope this helps

 

Thanks for the reply....I think I can get the used head pretty cheap, should/could I just swap them out?

 

it shouldn't be a problem as long as the head and vavles are in good shape. be sure to replace all gaskets and time it right and it should be fine.

 

thanks again for pointing me in the right direction.