New Comet 40 series belt problem

S

Sandcracker

Member
#1
#1
I got a new driver for my comet 40 series to fit a new engine I had. Got the bike running, and now when I rev up at all the driven opens ALL the way, and the belt gets pinched and the TC stalls. The driven shouldn't open that much. Does anyone know why this is happening?
 
S

Sandcracker

Member
#2
#2
Okay so I scooted the engine back, but it wouldn't go very fast even at high rpm. The belt is really hot too. That makes me think the belt is slipping.

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S

Sandcracker

Member
#5
#5
I'm pretty sure it's an alignment issue. It's a symmetrical belt. It's the right belt. It's able to be the proper length. My motor plate is slotted. I machined a washer to space the driver out. I'm out of wiggle room in the jackshaft. It's too close to the chain as is. I'll take pictures in the morning when I'm not so tired. Thanks for the help.

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Stangrcr1

Stangrcr1

New Member
#9
#9
View from the back(last pic) shows the problem. The back of the drive and driven pulleys should be parallel. Your belt runs at an angle.

Any chance of flipping the rear wheel over and running the chain opposite side? Then you could get the pulleys aligned.
 
gumpit

gumpit

#10
#10
Are you sure the back pulley(driven)is symmetrical and not asymmetrical? I think you have a 30 series asymmetrical on the back. A 40 series should have the spring going the other way.like the picture.
 
Last edited:
gumpit

gumpit

#11
#11
Symmetrical will have an angle on both sides. Asymmetrical will have an angle on one side and the other will be flat. Take off the belt and look at the driven and see if it is flat on the side closest to the frame.
 
gumpit

gumpit

#12
#12
I just went back and saw you are using a 40 series because of the size of the engine. You would have to make sure if it is a 40 series driven that it is turned around. Then extend the jackshaft to the other side and put the sprocket on the other side and run the chain to the rear tire on the right side by flipping the tire around like mentioned. Also did your yellow spring on the driven unwind when you drove it going in the reverse direction?
 
matt2

matt2

New Member
#14
#14
I am new to the comet belt setup and have been trying to figure it out my self. If you have the right driver to match the driven comet setup your belt looks to sit to low in the driven or rear pulley. It also looks like the belt is too tight. It is all about the center to center distance between the driver and the driven pulleys. Your rear driven pulley is either 7.5 or 8.5 inches. Once you know your pulley size and belt number you can look up the correct distance between center to center. You need to make sure your setup is all 40 series. Here is a picture of my Heald VT-5 look how the belt fits. Good luck


 
matt2

matt2

New Member
#17
#17
Here is another pic of a different 40 series on a different bike see the rear belt. level or just above the pulley. Enlarge the picture to see it.

 
S

Sandcracker

Member
#18
#18
gumpit said:
Are you sure the back pulley(driven)is symmetrical and not asymmetrical? I think you have a 30 series asymmetrical on the back. A 40 series should have the spring going the other way.like the picture.
Click to expand...
It's actually a 44 series symmetrical on the back. Also, you're right. the spring needs to go the other way. However, this means i need to put my chain on the other side like you said which means the brake has to switch to the left side. Does anyone know how to do that on the Mini baja?
 
S

Sandcracker

Member
#19
#19
gumpit said:
I just went back and saw you are using a 40 series because of the size of the engine. You would have to make sure if it is a 40 series driven that it is turned around. Then extend the jackshaft to the other side and put the sprocket on the other side and run the chain to the rear tire on the right side by flipping the tire around like mentioned. Also did your yellow spring on the driven unwind when you drove it going in the reverse direction?
Click to expand...
The spring didn't unwind. Before I changed engines, this driven in this setup worked perfectly. I guess I got lucky. :shrug:
 
matt2

matt2

New Member
#20
#20
Have you checked to see that all 3 of the plastic buttons are in the driven pulley? I was missing one and my belt ran low in the pulley.




 
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