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

dwcopple

backyard hooligan
Messages
192
Reaction score
1
Location
Mid-Michigan
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

Canned Monster
Messages
8,241
Reaction score
4,463
Location
Mayberry, Indiana
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

Well-known member
Messages
4,372
Reaction score
1,639
Location
Toledo, Ohio
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

Well-known member
Messages
2,363
Reaction score
546
Location
North east Ohio
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"
Messages
2,899
Reaction score
888
Location
Jacksonville, Florida
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

backyard hooligan
Messages
192
Reaction score
1
Location
Mid-Michigan
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.
 

Attachments

  • 20220502_171422.jpg
    20220502_171422.jpg
    3.3 MB · Views: 4

dwcopple

backyard hooligan
Messages
192
Reaction score
1
Location
Mid-Michigan
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

Well-known member
Messages
2,363
Reaction score
546
Location
North east Ohio
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

backyard hooligan
Messages
192
Reaction score
1
Location
Mid-Michigan
Well @3500rpm with 20" rear tire and 10/60 I only get like 36mph. The guys on YT are getting near 50mph+
 
Top