Max Clutch Offset

[Brock Landers]

Does anyone know what the offet should be between the drive amd driven clutches on an old max if any? It originally had a JLO 297 in it and I am installing a Rotax 399 with the same kind of drive clutch. I have to make sure I mount the engine correctly.

[Mike]

The offset will be 3/16" to 5/16" depending on the model of clutches you use. As long as you leave yourself some kind of adjustment both front to back, to tighten the belt, and side to side, to align the clutches, you should be fine. It's not much of an offset. There is a pictures somewhere in the gallery showing the offset.

Edit: Here is the picture

[Brock Landers]

Thanks Mike! I searched and didn't find that. Realistically, how precise does the offset need to be? 1/8" one way or the other doesn't seem like it would make a huge difference.

[micmac]

In my experience offset is extremely important at high Rpm's for two stroke machines. I had a slight mis-alignment and at high rpm the belt twisted in the clutches and exploded landing about 50 ft from the machine. Now what I do is open the driven clutch (I do this without the spring but not necessary) then push the belt down in the secondary were it would be at high rpm. Then I take a long straight edge and line up the edge of the belt in the secondary with the top of the fixed sheave on the drive. I use a long enough straight edge to stick out past both clutches. That way you can also check parrallelness as well.

Mike

[Rock Doctor]

Thanks Mike! I searched and didn't find that. Realistically, how precise does the offset need to be? 1/8" one way or the other doesn't seem like it would make a huge difference.

Just a quick note.
Part of my job at work is "Vibration Analysis" on rotating equipment. It can be very involved, but really, in most cases, vibration is caused by one of two things (or both). Misalignment, or Unbalanced, are the most common conditions.
Misalignment is not as much of a factor on belt driven equipment, but it is still important to get it as closely aligned as possible.


RD

[smog]

The offset will be 3/16" to 5/16" depending on the model of clutches you use. As long as you leave yourself some kind of adjustment both front to back, to tighten the belt, and side to side, to align the clutches, you should be fine. It's not much of an offset. There is a pictures somewhere in the gallery showing the offset.

Edit: Here is the picture

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is there a 4 strokes version ?

[Brock Landers]

In my experience offset is extremely important at high Rpm's for two stroke machines. I had a slight mis-alignment and at high rpm the belt twisted in the clutches and exploded landing about 50 ft from the machine. Now what I do is open the driven clutch (I do this without the spring but not necessary) then push the belt down in the secondary were it would be at high rpm. Then I take a long straight edge and line up the edge of the belt in the secondary with the top of the fixed sheave on the drive. I use a long enough straight edge to stick out past both clutches. That way you can also check parrallelness as well.

Mike

Interesting. I certainly don't want that happening. What does that mean then at lower RPMs?

[micmac]

The force applied to the CVT at the lesser RPM is not nearly as much as the at the higher RPM.

[Brock Landers]

In my experience offset is extremely important at high Rpm's for two stroke machines. I had a slight mis-alignment and at high rpm the belt twisted in the clutches and exploded landing about 50 ft from the machine. Now what I do is open the driven clutch (I do this without the spring but not necessary) then push the belt down in the secondary were it would be at high rpm. Then I take a long straight edge and line up the edge of the belt in the secondary with the top of the fixed sheave on the drive. I use a long enough straight edge to stick out past both clutches. That way you can also check parrallelness as well.

Mike

Mike, can you explain this in more detail? Belts are wedge shaped and the drive clutch is made up of 2 curved surfaces so do I line up the top (wide) edge of the belt with the very top of the fixed sheave? Thanks for your help.