Whining noise
 

Ever since i had all of my internals and BBK swapped over to the new bored out case, i have had this whining sound whenever the engine gets up and going. I can only hear it when the i hit the gas. Nothing at idle. The higher the rpm, the louder the whining. The guy who put the engine together origionally said it sounded like the CVT belt. It does sound like its coming from the CVT case, but what could it be? I can hear it while im riding it or its in park and i rev it.

I don't have a clue what it can be, but if you use a piece of garden hose or some tubing it might help you isolate the sound ( use it like a stethoscope).

Check ur oil in the gear case maybe? Could be ur Main driven gear making the whinning sound

your hearing the internal trans shaft bearing getting ready to explode! No joke! They whine for a while before they come apart. Very distinctive whine. Terminal destruction! The trans locks up and destroys everything inside including the main motor case. Been there- done that

Glad to know I was close at least. We both have trailmaster xrx 150s but I have yet to experience this. I run Lucas 80-90w in my case

Somewhere in the forum there is a video of a yerf on a trial run. You can distinctly hear that tell tale sound of emanate trans bearing failure. May have been one of x-bird's early vids, I can't remember. I tried a search but no luck.
Perform a trans over-haul before the bearings cut loose and there's no harm /no foul. It's a simple job. disassemble then reassemble with fresh bearings. Waiting too long equals major carnage.

Most of the time it's the inside bearing on the output shaft . That bearing is located at the highest point in the trans. Because lubrication depends on gravity and the gears themselves to pick up and distribute oil, that bearing is prone to starvation, especially if the oil level is not maintained.
Over filling the case slightly by tipping the motor (a couple of tablespoons) won't hurt and gives that bearing a little help. Make sure the trans vent is clear and unrestricted. There may be some initial oil blow from the vent tube but that goes away as the oil level and internal pressure balances out.

yes, that was mine, Ckau saved my engine/trans by giving me the heads-up. pretty simple repair, bearing replacement and new gasket.--not a bad idea to toss in an oil seal while you're at it. if the output shaft isn't worn you're good to go. mine was worn and finding a replacement was difficult because of the oddball nature of my engine.
About 1:21 in this video you can hear the sound it makes when the gears aren't meshing properly.
http://www.youtube.com/watch?v=IQ5OE6h6aW0

I always fill my trany oil all the way till it starts to come out of poor hole. Lucas 80w90gearlube. Now motor oil I put the recommended amount. Motor is differant.