Srxspec
Your #1 performance shop!
Ok, after having a customer come in and tell me his sled runs great, but bogs off the start, I went out and checked his belt deflection to find he had about 3" of deflection! 
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.
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.
98srx6
New member
Very good post Srxspec...as usual.
Spec - I just put a new belt (OEM) on my 01 SRX. When on a stand it turns the track SLOWLY, but it also squeals pretty bad. As such, I pulled the secondary and removed a small shim from each of the three deflection bolts. It eliminated the squeal but now the belt sits just even or maybe a HAIR below the top of the secondary. I thought it should be a little above on an SRX. ALso the center to center and alignment are perfect. What do you think?
Thanks
Thanks
I have that exact problem on my 700 vmax. Is Yamaha making their belts narrower than previous years. I noticed the problem first with last years belt!
Harvey
New member
they have different thickness washers for those 3 bolts on the back of the secondary,try a thinner set.-Harvey
vipertripplexxx
New member
If you want to do it right, put the washers back in, and set the center to center on the clutches so the deflection is correct. Check you offset while your at it. Removing the washers, changes your offset.
Steveo
Steveo
Srxspec
Your #1 performance shop!
If your new built is squeeling when the last one didn't it's because your new belt is shorter than your old one was. The belt should ride roughly 1.5mm (.060") above to .5mm (.020") below the top of the secondary sheaves.
Moving the center to center every time you buy a new belt and it squeels is alot of works for most of your average trail riders. Adjusting with the washers on the three (3) bolts on the backside of the secondary works just fine. As long as you don't have your secondary "locked" there is no need to worry about the minute amount of movement which is caused by removing any washers from those three (3) bolts on the back side of the clutch affecting the alignment.
vipertripplexxx said:
Moving the center to center every time you buy a new belt and it squeels is alot of works for most of your average trail riders. Adjusting with the washers on the three (3) bolts on the backside of the secondary works just fine. As long as you don't have your secondary "locked" there is no need to worry about the minute amount of movement which is caused by removing any washers from those three (3) bolts on the back side of the clutch affecting the alignment.
vipertripplexxx
New member
Yea, thats what I meant to say! LOL. Check center to center, and adjust washers to get belt deflection you desire. I guess I've never had that much of a problem with new belt variation. What are the advantages of a locked secondary?
Cheers, Steveo
Cheers, Steveo
Last edited:
yamyrider
Active member
I put in a new belt and it's sitting about 1.4mm higher and it squeels like a pig at idle. The center to center is right on. My old belt had just stoped squeeling. Even though I am within specs should I remove a washer on each screw to lower the belt.