floating

I am mounting a 30 series driven on a keyed jack shaft. Does it have to be held in horizontal position with a pair of collars or can it float?

I have the 212cc predator clone and recently installed the OldMiniBikes stage 4 hemi on my DB30, the kit doesn't come with upgraded valve springs. It has the mod 2 cam and I can't find any 22 lb springs to turn 7,000 rpms. It is floating the stock valves. Can someone point me in the right direction on...

Does anyone know the symptoms?

Hi guys. I have seen quite a few Tecumseh motors, horizintal 5-10HP, where the exhaust valve opens slightly during compression. So far I've just ground enough off of the valve stem so that it stays closed. Anybody got some advice? Thanks,