So, if the belt runs true and in the middle, does that mean that there will be no noise at all? If it is as [relatively] easy as that, why are so many cars suffering from so much noise?
Good question Paul...
But as I've suggested, starting with the belt properly aligned is a good staring point. If it's noisy after the belt is properly centered, address the next thing that could cause it.
But to be honest with you, I've been on a few Harley forums for many years and I've never heard of anyone complaining about a noisy rear belt. That doesn't mean there aren't some, but not enough of them to be an item to start a thread about.
I really can't put my finger on the problem for your noisy belts, but there has to be a reason. Lubricating or coating the belt with secondary "stuff" is not the true long term answer.
We use 8mm Polychain profiles on our machines and they run 24/7/365 and we have no complaints about noisy belts. As I've shown on another thread, we water jet cut all of our pulleys based on profiles supplied by Gates. Our pulleys are not sent out for coating, we run them bare aluminium. They are also a bit rough as we run our water jet at a mid speed on the cutting path.
As far as belt tension goes, I'm not going to offer, but I can tell you that if they are too loose, they tend to climb the teeth creating a LOT more pressure on the belt and that's when most belts break; running too loose.
On my Willys with the GMC 6.71 belt driven blower, I had to drill my pulleys with very fine bits to release the air trapped under the belt as they turned. In my case I had a Gilmore 1/2" pitch 3" wide belt and that did trap air in the teeth. This created lot of extra "unwanted noise. I say unwanted as it's quite a nice noise to have is the whine of the GMC blower setting on top of your big V-8. Some guys take out their nice quiet timing chains and replace them with straight cut gear drives for their cams just to get that "blower whine".
I'm sure though at only 1.5" wide on the belt that it's not going to be air trapped making the noise.
But if MMC is having their pulleys made up on a CNC mill, there could be some type of profile inaccuracies that could be the cause too. They buy the belts from Gates so they're locked in there. So it has to be the pulleys, alignment or tension etc.
Sorry for rambling. My fingers get typing and I can't shut them up!
