What sprocket and chain size should I purchase.

B

Bandit67

New Member
Guys, fairly new guy here at rebuilding these fun bikes. Bought a basket case HKO in need of lots. Purchased a 110 Lifan manual four speed engine. It came with a 14 T, 428 size front sprocket. I need a new rear sprocket. I believe, originally HKO's came with 14t-45t 420 size chain.. Not sure which way to proceed. I see rear sprockets listed in sizes from 35 thru 45t, BUT all seem to be for 420 chains. Im not sure you can run a 420 chain on a 428 sprocket, but I would think not. Do I just need to get a 14-45 kit for a 420 chain or does the bigger motor need the bigger size chain. thanks for your opinion.......
 
No rear sprocket for the rear in 428 flavor for a ct70. With the gearing side, you will have to test. I like to run the biggest countershaft sprocket as possible, =s less chain wear. Test with different counters, they are cheaper.
 
16-38 would be a good starting point if buying both with a new 420 chain, and 428 do not mix. Counter is 17mm OD or 20mm OD. Double check like dirtbkr188 said.
 
Thanks Guys, now I understand. The Lifan motor fits many other engines/applacations that do use the 428 size but our ct70s do not. Would the 16-38 be faster than the original 14-45 or about the same, thanks
 
Here's something to help you decide...

Final Drive Ratios - 5.jpg
 
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