150cc GY6 Final Drive Ratio

slowhand · 07-24-2022, 02:04 PM

So I'm trying to figure out my insufferable top speed problems. I'm wondering if my transmission drive gears are the wrong set (an underdrive set). According to the NCY webpage the output drive gear ratio should be 40:13. I don't want to open up my transmission output gear housing unless I can confirm that I don't have the requisite 40:13 ratio.

I removed the CVT cover, put the valve of the rear wheel at the bottom of rotation, marked the bottom of the clutch bell housing, and spun the wheel around once. The clutch bell turns ~8 1/2 turns for each one rotation of the rear wheel. Is this correct for a 40:13 gear set? Has anyone checked the final drive ratio on their GY6? Do you know if your gear set is a 40:13?

Thanks.

chinazuki · 09-19-2022, 02:27 PM

I dont know much about these things, but....No the two ratios you listed are not even close.

also it may be that you have a two-speed trans that changes based on rpm. You are only seeing low gear.

chinazuki · 09-19-2022, 02:30 PM

changes based on wheel rpm

07-24-2022, 02:04 PM	#1
slowhand Join Date: Mar 2022 Posts: 26	150cc GY6 Final Drive Ratio So I'm trying to figure out my insufferable top speed problems. I'm wondering if my transmission drive gears are the wrong set (an underdrive set). According to the NCY webpage the output drive gear ratio should be 40:13. I don't want to open up my transmission output gear housing unless I can confirm that I don't have the requisite 40:13 ratio. I removed the CVT cover, put the valve of the rear wheel at the bottom of rotation, marked the bottom of the clutch bell housing, and spun the wheel around once. The clutch bell turns ~8 1/2 turns for each one rotation of the rear wheel. Is this correct for a 40:13 gear set? Has anyone checked the final drive ratio on their GY6? Do you know if your gear set is a 40:13? Thanks.
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09-19-2022, 02:27 PM	#2
chinazuki Join Date: Sep 2022 Location: arkansas Posts: 43	I dont know much about these things, but....No the two ratios you listed are not even close. also it may be that you have a two-speed trans that changes based on rpm. You are only seeing low gear. __________________ arkansas
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09-19-2022, 02:30 PM	#3
chinazuki Join Date: Sep 2022 Location: arkansas Posts: 43	changes based on wheel rpm __________________ arkansas
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