cheapest place to order/purchase #40 chain and rear sprocket?

dwcopple

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I'm building a Predator powered dirt bike and need a good inexpensive place to order some #40 chain and a matching rear sprocket 44-48 tooth. Any vendors that give forum members a discount? Where is your go-to place?
 

Denny

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Just go to Tractor Supply. That’s what I do. Sure, I gotta drill my own mounting holes but hey I’m cheap. Also broke.
 

Functional Artist

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BMI karts has a variety of sprockets
...& hubs

Here is a 48T sprocket for 40/41 chain (~$21.00)
...with (2) sets of bolt holes already in it.

https://www.bmikarts.com/Sprocket-4140-48T-Dual-Bolt-Circle_p_16985.html

Here are the
Product Specs:
  • Steel Plate Sprocket
  • Chain Pitch: #41/40
  • Teeth: 48T
  • 2 Bolt Patterns:
    - (4) bolt pattern for 5/16" bolts on a 2-13/16" bolt hole circle
    - (4) bolt pattern for 3/8" bolts on a 2-7/8" bolt hole circle
  • The center bore is 2.12"
With maybe a hub like this (~$12.00)
https://www.bmikarts.com/Steel-Multi-Patterned-Sprocket-Brake-Hub-1-Bore-_p_1404.html
 

karl

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48t is not big enough , you will need a jackshaft between the motor's clutch or torque converter to compound
the gear ratios. Or a much bigger sprocket, think 72- 100 teeth.
 

madprofessor

"Loose Cannon Creations"
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Wow. I guess you really do need to replace that rear sprocket. I could surf on the curves in those folded over teeth. Was the chain skipping teeth under load when you rode it last?
 

dwcopple

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Wow. I guess you really do need to replace that rear sprocket. I could surf on the curves in those folded over teeth. Was the chain skipping teeth under load when you rode it last?
It's a parts bike I'm stuffing a Predator into. Never had an engine in my hands. Guys that built these on YouTube are running 10T driven and 45T rear off the TAV2. Not sure why guy above is saying 75-100 is necessary.
 

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dwcopple

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I agree. So would a 60 tooth be fine with my 10T drive sprocket? Seems to be limited options. Also, should I run 420 chain instead of 40?
 

karl

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I don't see how that calculator works when you have a CVT trans though. Please explain.
Simple, The torque converter adds 10% overdrive in top gear. Add that to the RPM in the calculator.

Or ignore it, 10% will usually not make or break it. If your gear ratio is way out of wack,10% is not making the difference...
 

dwcopple

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Well @3500rpm with 20" rear tire and 10/60 I only get like 36mph. The guys on YT are getting near 50mph+
 
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