I have painted some suspension parts with single stage acrylic enamel. should I put clear acrylic enamel on top or leave as is? thanks

All paint sytstems are different, but I would not put clear over single stage. First clear needs to be applied with in a specific time frame to the base coat for adhesion. if you have already applied the color this time frame has past. Second on exterior parts the sun can cause damage to the C/C if applied over single stage. Note base color has little to no shine when applied, and the clear provides the depth and shine. If exposed ot the sun the heat will cause a problem.
This was explained to me by a PPG factory rep.

Short answer no clear