Shaw Cross Sharks recent winning run was brought to a disappointing end as they lost their fifth home game of the season.
The Sharks fell behind early in the game and were unable to find their way back into the tie, the loss sees Shaw Cross remain in seventh and they are now four points away from the play-off positions.
One of the highlights of the afternoon was the return of Adam Masson who took to the field for the first time in almost a year after recovery from an ACL injury.
Acorn opened the scoring as the visiting hooker picked the ball from dummy half and made a dart for the line and got the ball down by the posts.
The visitors soon doubled their lead as Shaw Cross lost the ball in their own half, advantage was played and York bundled their way over the line to stretch their advantage to 12.
Shaw Cross responded with a try of their own after they received a penalty for a late tackle on Paul March.
Ross Roebuck ran a perfect line and powered his way over to reduce the deficit, however the successful conversion from Johnson proved to be the Sharks’ last points of the afternoon.
York were temporarily reduced to 12 men as their hooker was sent to the sin-bin for striking in the tackle.
The away side added a penalty goal shortly before half-time to extend their lead to eight points.
Dec Ellis soon got over for Shaw Cross but saw his try chalked off for double movement.
The hosts almost found their way over the line quickly into the second half after March broke brilliantly up the field but a knock down from the York full-back prevented the Sharks moving the ball into space for a potential try.
York increased their advantage further as the prop was first to the loose ball to get the try, the referee conferred with his touch judge before awarding the score.
The Sharks were then reduced to 12 men as Nathan Smith was sent off for allegedly throwing the ball at the referee.
Brandan French then got the ball down for Shaw Cross in the far corner but his try was disallowed as the referee called play back for a Shaw Cross penalty.
Sam Ottewell broke up the field but was held in the tackle by the York centre Matty Woods, Ottewell attempted a quick play the ball but received a knee to the head for his efforts.
A short scuffle ensued between the players before Woods was sent off, Ottewell was sent to the bin, it was unclear as to why the Sharks stand-off was shown yellow.
Play was brought to an end moments later as the full-time whistle was blown.
Updated 09:55 - 5 Jun 2017 by Ben McKenna
Shaw Cross next game is this Saturday as they host opening day opponents Underbank Rangers at Leeds Road (2:30pm).