Was there metal in the oil when they did the full service before the knocking? If so they were you told? Usually metal in the oil is indication of some serious trouble inside if it’s not an engine being broken in. You shouldn’t have ridden it after that.

 

 

ok so tell them they should have told you about the metal shavings in the oil. Riding an engine in that condition accelerated the demise. THey should fix it either for free or at a discounted rate.

 

^ I gotta agree that there is most likely a bad rod bearing and they should have told you about the metal the oil. The unfortunate thing is that you can't prove they did anything wrong other than not telling you the engine is toast. They don't work for free so, yes expect to pay to have them pull it apart.


You say it started to knock while you were riding it, that says it wasn't knocking while they had it. Also, you say you are new to riding, I take it that you purchased the bike used. If the previous owner was doing wheelies, standing a bike up on the rear wheel can cause the oil pickup not to deliver oil to the mains and rod caps. That may have caused the original wear on the bearings and then they fail while you were riding.


Unfortunately, there may not be a happy ending here. It would cheaper to replace the engine yourself than have them pull it apart and fine that they need to replace it.
If it is knocking with metal in the oil, I'd say new bearings and crank at a minimum.