help diagnose my Hustler CVT issue

[LarryW]

Based on info I read in a snowmobile book my dad had laying around, there should be an offset. The amount depends on clutch brand. I uploaded the diagram from the book and put the offset amount for a salsbury clutches at the top of the picture. It makes sense if you think about how the clutches move.

http://www.6x6world.com/gallery/show...o=6296&cat=661

Good point ES-H!! I think you have to look and match up the 2 fixed faces up. Thats how I do it. I believe your belt is factory defect because that is strange to me for it to rip like that. I have had some pretty mismatch clutches run with out doing that. Although Im sure they wore down a lot quicker.

[micmac]

ES

Thanks for the schematic that helps. Looks like the drive clutch fixed edge should be about 3/16 or 5/16 offset inboard from the driven when static.

DH,

I looked at the clutch and it moves in and out only an 1/8 inch not the 1/4 as I previously stated. Can anyone confirm there should be no play in and out on the driven clutch?

Larry

If you matched up the fixed edges wouldn't the belt be angeled significantly as they are on opposite sides

[micmac]

I just read an alignment trick from the snowmobile forums similar to what ES-Hustler suggested. Take a long enough piece of small (like 1/4 inch) square tubing. take the belt off, open up the driven clutch lay the tubing between the two sheaves as far down as possible and laying across the top of the primary clutch. Let the spring on the secondary clamp the tube and poof instant alignment tool to take measurements from. Too easy wish I could have thought of that.

[brushcutter]

I'll check one of my machines that is still stock and see what the offset is on it. I'll also check for the transmission endplay so maybe we can figure out if this is normal, but I am almost certain that there should be "some" play. If not, all of them I have ever worked on... were wrong

[LarryW]

Larry

If you matched up the fixed edges wouldn't the belt be angeled significantly as they are on opposite sides

I wasnt specific on my post. I use them for adjusting because they dont move. The top of the driven should be near the bottom face of the drive, but not the exact bottom because the thickness of the belt. Im not sure but in my eyes the belt will slide down on the driven side moving sideways because the fixed side dont move. which is sliding the same direction the fixed face is which it climbs. Its just there fixed and dont move so its easier for me to think of it that way.

I adjust mine with the belt on. Push down on the bottom of the belt and tightens the upper part and look down it.

I have had really miss align belts run without doing the damage your has. I would say defective belt but it sure would suck to buy another and have it do the same. Like it was already stated the driven does have some play in it. Maybe you could post a thread asking about the play. Im not sure if that normal or not.

[jerseybigfoot]

The issues you are having are with mixing and matching components. If you are changing belt width, the engine side has to be shimmed for the belt width as well as the trans side. Just remember the moving side of the engine clutch has to shift to pinch the the belt to the fixed side. If the belt is centered at rest and there is a big gap between the belt and the fixed sheave belt center line has to move over that distance to before you have pinch. With an engine clutch that has allot of clearance I would run the belt closer (with a minimum clearance) to engine fixed sheave.

[jerseybigfoot]

Looking at your video again I think the vibration is just an anomaly an will not effect the CVT performance. Matching the springs and weights in the CVT and tuning the system is another issue.

[micmac]

Thanks everyone for their help on this after taking a bunch of measurements today here is what I found:

The shafts are parallel

The engine could stand to move outboard as suggested by jerseybigfoot but only a very small amount

I ran the machine under working load and the vibration was much less noticeable.

That brings me back to the belt failure. I think (more hoping than knowing) that it was a combination of a few things:

The belt may be too short I'll install one 1/2 inch longer.
It may have been defective
I will break in a new belt under lower power settings when replaced

For now the old one seems to be working fine and I'll run it hard for a while to see if anything else comes up.

I want to thank everyone for helping out on this it's the reason this board is so great.

Thanks again

Mike

[Model Citizen]

Whipper & I checked everyone of our driven clutches on our cars & each one has different amounts of endplay. Don't know if that makes you feel any better about ruling out endplay causing the problem you had. Whipper says he's never seen a T-20 that hasn't had some endplay.

Question? Do you have an adjustable engine mount so you can adjust the tension no matter what belt you use, because even if you go 1/2" longer, you'll have to adjust it somehow?

It really is sounding more like a defective belt. &%#* happens sometimes.

Bridget

[micmac]

Bridget and Whipper,

Thanks for checking on your machines that helps a bunch and alleviates any fears I have about the t-20 clutch. The way I built my mount you can adjust for tension, problem is that I'm at the forward limit so if I start with too small a belt I "gots" no where to go.

Now for the rest of the story.... I had the machine in the driveway today finishing up an engine issue that I ended up solving (1 step forward). I decided to run the engine up to test the settings all the while keeping a watchful eye on the belt from a safe distance. At high rpm suddenly I see the belt actually TWIST on the clutches and BAAAM the belt snaps and goes 30 yards into the street (two steps back). As you can imagine I'm not a hero with the stroller pushing soccer moms from neighborhood out for their morning stroll.

So I'm back to the drawing board. I'm going have to align the engine better and get a longer belt and go from there.

Mike