How to fix burnt Valves?

[bmw633]

Hi,

I am looking at a bike that has the head off due to burnt valves. Can new valves be swapped out and everything put back together, or do the valve seats need to be machined?

Are there any engines other than the stock engine that could be mounted?

[alantf]

Originally Posted by bmw633

Hi,

Can new valves be swapped out and everything put back together, or do the valve seats need to be machined?

Never done it on a bike, but when I used to work on my car, I found that unless the valve seats were really badly pitted, then they just need "lapping in". To do this you need a "lapping" tool. This is simply a stick with a sucker on one end. You apply grinding paste (coarse then fine) to the valve seat, then put the valve in place. Push the sucker on the flat end of the valve, and spin the stick back and forth between your hands to grind the valve & seat to match each other. This needs to be done in all cases, to ensure a gas tight seal between valve & seat.

[raul10141964]

you ca take the head to a machine chop and they will test and install the new valve for you