tiny parts of metal are quite normal for the first one or two oil changes in any new bike when its attached it self to the drain plug if magnetic drain plug,if it persisits as the miles add up i would inform your dealer,best way to flush engine is to drain the original oil and fill up with cheap oil run it up to temp and flush it out,then refill again with cheap oil and flush again till no particles of metal can be seen,then fill up using the regular oil and change out the oil filter for a new one...imo...if there chunks of the stuff i'd be worried....lol