How should I set my belt deflection?

Best Belt Deflection = Track Movement:
First lift the sled onto your track stand, start the sled, warm the engine up and "rev" the engine to turn the track. Get the track nice and limber (meaning get the "cold" out of the track and loosen it up from any stiffness it has from sitting). When the sled is on a track stand and the engine is started and idling the track should:

A- Creep slowly.
B- Turn with jerking movements.
C- Track is still but you are able to move it by pushing lightly on a lug with your hand.

You should now already have proper belt height on the secondary after setting your deflection up like this. If you cannot get this kind of deflection change the drive belt to one that fits with proper length. The belt you achieve this with will be the one you want to keep. When buying a new belt, if possible take a seamstress tape with you and measure the belts circumference and make sure it is always the same.

If you laid a flat edge on top of the belt from the center of your secondary to the center of your primary and pushed down on the belt roughly in the middle you should have no more than 1-1/4" of movement when pushing down on it.

Your sled will never bog with these conditions. If you have found that your track moves on the stand at idle, then great! As long as your track moves or needs just a bit of help with just a finger or two you have great belt deflection!

Effects of Improper Belt Deflection:

Too Tight of Deflection:
When the belt deflection is set too tight the belt burns the cogs when sitting and idling anywhere near or below engagement. It also increases the torque at holeshot (which creates a better holeshot) but the top end mph is lost.

Too Loose of Deflection:
The holeshot will suffer and possibly bog and the midrange punch will be slow and doggy. It is possible for the midrange mph to be higher if the engine stays close to the proper operating rpm, but the top end rpm will pull down.


