The reaction kinetics of styrene and indene with cyclopentadiene in the presence of tert-butylcatechol as a polymerization inhibitor was studied in a batch reactor in the production of potential monomers for amorphous polymers: 5-phenyl-2-norbornene and indenylnorbornene. The experimental results can be explained with a reaction mechanism using four separate reactions: an equilibrium reaction of dicyclopentadiene and cyclopentadiene, a Diels-Alder reaction of cyclopentadiene with a dienophile to produce norbornene, disproportionation of norbornene, and a reaction between norbornene and dicyclopentadiene. Some polymerization could be noticed when an excess of dienophile was used. The reaction kinetic parameters of this mechanism were fitted and their reliabilities tested using Markov chain Monte Carlo (MCMC) methods. The suggested reaction mechanisms explained the experimental results well, but analysis with MCMC methods revealed clear uncertainties in the reliabilities of the estimated parameters. Here, MCMC provided a useful tool for analyzing in detail what the measured data tell about the unknown parameters and how reliably they can be identified.