Engine Paint

I have used it on bike parts but have found it to take forever to harden , this may result in the rubber seal  "bonding" to the case. Its not very hardwearing. 

If you are using it only on the engine plates and not the motor itself the Smoothrire spray paint is excellent. No need of primer, just a good clean surface.

Use hammerite thinner to wipe over the parts ,any oil specks will ruin the finish.

I used to use Hammerite a lot years ago but more recently found it to be a thin and miserable finish  A search turned up the following article

https://www.model-engineer.co.uk/forums/postings.asp?th=97920

The thinners were indeed a source of trike when that became unobtainable

Have been using Carplan  highbuild primer and top coat which seems to last pretty well

Laurence