The absolutely MOST important aspect of a CVT drive train is making sure that it's perfectly aligned.

A correctly setup and aligned CVT system will last, doesn't eat belts, generally doesn't suffer from heat issues and works as designed. Get just an itty bitty twist in the system and poof, belts start getting eaten and they don't like high speed runs - they usually protest by disintegrating.

Perfect alignment is when the engine crankshaft centerline and transmission input shaft centerline are parallel to each other.

I thought I'd put together a quick tutorial on how I've set my CVT systems up over the years with great results. No special tools needed, just a couple of straight edges and some clamps. A flashlight and/or good lighting will help.

I always mock up both the transmission and engine's position to get an idea of where things are going to fit/clearance issues, etc.. Once I have them "located" I'll mount the transmission, paying strict attention to making sure the input shaft is perfectly level (as should be the chassis) and that it's perfectly perpendicular to the center line of the car as if you're looking down from the top. It MUST be 90 degrees to that imaginary line running down the middle of the car or you'll induce twist and twist is bad.

I actually suspend the engine with tie downs to get it in the correct location.









So first thing would be belt length. I'm from the school of longer is better - more cooling, more surface area but that isn't necessarily a required thing. Get an idea of where components fit, do measurements between the engine's crank and the transmissions input shaft and then do a bit of research. I know there are web sites that have the info, just don't know where. Search Team Industries, maybe someone like Gates who makes belts or even some of the sled mfgs.

If you're doing a UTV trans, grab the stock belt and work with that if engine clearance will allow.

For center to center distance I've always just sort of winged it.

I make sure that the teeth in the back side of the belt just barely stick out of the secondary with it fully close, that the belt is seated in the bottom of the primary and then pull the engine and trans apart until there's a slight amount of tension. This is where having the engine hanging with straps is handy - you can pull tight/loosen as needed to get the engine located appropriately.

You should be able to turn the secondary with just a little drag feeling.

If it can spin easily, the center distance is too short (loose). If you have a lot of drag and a hard time turning it, you're too tight. There's sort of a magic spot you'll be able to feel. It goes from loose to a tad of grip but not sticking. If you get it wrong, don't worry - belts sizes are plenty and you can always bump up or down 1/8" to adjust the tension. - or your secondary may be adjustable to open/close it and adjust tension.

Once center to center is established, then next thing that seems to concern people is getting the offset correct. The offset will come automatically as long as you get the belt centered in both clutches.

You need to use a straight piece that's the same width as the belt you plan on using. The tighter it is between the primary clutch faces, but still against the center shaft, the better. Try to avoid having any slop so the straight edge can't move left/right in the clutch. The fit in the picture below is perfect.



The straight needs to sit all the way down into the primary, on the shaft and it will settle into the V formed by the secondary (upper end in pic above).

Clamp a straight edge of some sort to the back of the primary's inner face. Make sure you clamp it to the machined surface. The Yamaha clutch seen in this example has about 1/2" of machined edge and then it goes into the cast area that's not flat. If you get the straight edge against the cast, it'll not be square to the clutch. Pay attention to this - must be on the machined flat.



Once you get the belt mock up in, start getting it aligned. Measure the distance between the belt mock up and the straight edge. These need to be parallel.





This gets the belt perpendicular to the primary and gets the offset of the secondary automatically figured out. No need trying to find an offset number.

Now comes the fun stuff. This is sort of a two part exercise and you'll do both parts a bunch. You'll do a vertical and a horizontal alignment and often moving one moves the other.

Clamp a straight edge to both the clutches - once again, make sure they're clamped to a machined surface and not a cast area. The longer you can make them, the better (as long as both pieces are perfectly straight.)



Now take a flash light and shine it on one of the edges of the two straight edges. Move your line of sight so that the two edges start to come together.

Notice how the gap is tapered? That means the clutches are not parallel - that's twist.



Some adjustment and tada, the line's parallel.





When you move your line of sight, making the two edges merge, if you have back lighting and things perfectly parallel, the light will blink out. The whole edge will change shading in one sudden moment. If there's even a tad amount of misalignment the light along the edge will move and fade out (kinda like the sunset). You're looking for that "blink".

Now move your straight edges so they're horizontal.





Make sure that the straight edges are parallel, as looking from the side of the car. If they're not parallel, the alignment trick won't work.



Looking down from top, now do the trick where you compare the two straight edges. Once you get "blink", you're aligned.

Go back and check the vertical alignment, check your center to center (belt drag) and if all feels and looks good, you're done.

This may take a few shots at getting things in just right. Tack one engine mount (closest one to the primary) in to secure the engine to the chassis and then check the alignment. Tack in another mount (opposite corner), check alignment. Before you know it you'll have the engine solidly mounted and everything nice and square.