Hi Jayelwin
,
I know what you'd like to do is match your faded/discolored paint on the engine w/ some fresh touch-up paint from a can and then hope they'll blend... I've tried it and it will not look too good;now if you don't look TOO closely you may be able to get away with touching it up w/ a Very good match to stock paint that I've found.
I've used Duplicolor Engine Enamel(500 degree w/ ceramic)from a spray can and it's held up great and the color has blended well with stock OE Honda engine factory paint. The stock# is: 'DE1615 Aluminum' & got it at Autozone before.
The trick is in applying it by spraying it heavily into a large jar lid and getting it good and 'runny' in there and then using a small brush and quickly applying it one stroke at a time...
The best option though will be to prep the surface real good & mask off the places on your engine you'd like to do and then just go for it;you'll have to do lots of masking the second way(frame,etc.) I've done the first 'brush' method with good results for touch up only.