Hello I'm new to this site so forgive me if I wrong. I look in common threads for information on how to determine if I have a leaking valve but found nothing. I recently traded my yz250f for a yz426f that has been fitted with wr parts to make it street legal. It seemed to have a noisy valve train and coolant in the oil. So I have replaced the waterpump seals, bearing and impeller shaft I seemed to have fixed the contamination of the oil but upon start-up had a huge plume of blue smoke that clearer within about 45 seconds. I'm sure that this is a leaking valve, but would like conformation from you very knowledgeable folks. I was hopping that some one might say that they just need adjustment haha. thanks for your time.