YOu should change to CVD's. They hold up
plastic just can't do that. As for a Lehner 1900 serious good luck. They are hard to find. Chris Fine at Fine Design is the only dealer here in the US that I know of. He is out of stock with the 1900 serious. I called him last month about one. Here's a thead about that:
http://www.rc-monster.com/forum/showthread.php?t=7597
Good Luck. I found a used 1950. Great motor but "0" replacement help.