Hi I'm new to this world I'm building my first shifter kart it has 11x7.00-5 drive tires an a 1977 yz400d 2 stroke motor I'm running the motors stock drive gear with 520p chain I'm trying to determine what number of teeth I should start with on the rear sprocket any help would be appreciated
Gearing help
- Thread starter josh89
- Start date
anderkart
Moderator
Guys that race Shifterkarts (with 2-cyle dirtbike engines like yours) on a track typically have a 16 -19 tooth counter sprocket, and a 21- 30 tooth axle sprocket, depending on the length of the tracks straightaway & desired top speed. You could expect amazing acceleration using any of these gearing combinations on your kart. With your 8000rpm engine, you could probably expect top speeds to vary between 60mph & 100mph; depending on what gearing combination you choose.
You didn't mention what diameter your rear axle is, but here's a link to some shifterkart axle sprockets made for 40mm & 50mm axles. They're a 2-peice design with a built-in hub so It's super easy to change gear ratios:
Most all Shifter racekarts run #428 pitch sprockets & chains because no one seems to make #520 pitch axle sprockets in suitable tooth counts to fit the 1-1/4", 40mm or 50mm diameter axles that shifterkarts typically have. So guys replace their #520 counter sprockets with a #428 pitch that are plenty strong.
Here's a link to one for Yamaha's, but I don't know if it'll fit/interchange to your YZ400:
sharkshifter.com
There's serveral shops that will custom build #428 counter sprockets to fit your engine. You'd just need to do a google search using the term: 'custom counter sprockets for motorcycle' to find one.
Have you already figured out a motor mount, plus shifter & clutch linkage?
Does your racekart already have front brakes, or just rear only?
PS: post a pic of your kart
You didn't mention what diameter your rear axle is, but here's a link to some shifterkart axle sprockets made for 40mm & 50mm axles. They're a 2-peice design with a built-in hub so It's super easy to change gear ratios:
Most all Shifter racekarts run #428 pitch sprockets & chains because no one seems to make #520 pitch axle sprockets in suitable tooth counts to fit the 1-1/4", 40mm or 50mm diameter axles that shifterkarts typically have. So guys replace their #520 counter sprockets with a #428 pitch that are plenty strong.
Here's a link to one for Yamaha's, but I don't know if it'll fit/interchange to your YZ400:
Yamaha YZ-250F 01 to 20, 428 Sprocket 16 thur 19 tooth counter shaft
Sharkshifter offers all your yamaha YZ 250F drive gears & axle Gears / chains with one of the largest selection of shifter drive sprockets in the karting industries
sharkshifter.com
There's serveral shops that will custom build #428 counter sprockets to fit your engine. You'd just need to do a google search using the term: 'custom counter sprockets for motorcycle' to find one.
Have you already figured out a motor mount, plus shifter & clutch linkage?
Does your racekart already have front brakes, or just rear only?
PS: post a pic of your kart
Last edited: