need help on sprocket
Moderator: Rob Voska
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- Posts: 7
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- Vintage Karting items owned: 3 karts not sure of make
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need help on sprocket
building a gk1200,have an original stock mc7 with stock clutch (9 tooth), i am wondering if anyone can give me size(number of teeth ) for a low range ,mid range,and high range sprocket. not sure which way i want to set up yet, that's why asking for all 3. any help would be great and everyone have a good and safe day.
Re: need help on sprocket
Hi Ed. Welcome. Couple of questions. Where are you going to run this? If it's a track the length of straight. How much do you weigh 125 lbs or 250 lbs?
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- Posts: 7
- Joined: Sun Sep 20, 2020 4:27 pm
- Vintage Karting items owned: 3 karts not sure of make
- User Agreement: Yes
Re: need help on sprocket
weight is 185lbs. , not really sure where its going to be run,probably a track, but not racedat thi time. want to get an idea on gearing, low, mid, and high
Re: need help on sprocket
76-77 High
70-71 Mid
63-64 Low
Basing those off of a Mc91 at about 180 lbs.
R.E.A.R.
70-71 Mid
63-64 Low
Basing those off of a Mc91 at about 180 lbs.
R.E.A.R.
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- Posts: 1685
- Joined: Fri Jun 15, 2007 7:59 am
Re: need help on sprocket
Bob, his non-boost ported Mc7 will develop 2-3 horses less than a '91, and less bottom end with the small carb. It may need 2 or 3 more teeth on the bottom gear than a '91. The '7 needs to wind up. Ted
Re: need help on sprocket
Tire diameter will play into selection also.
Need to keep ground clearance in mind when going with a large tooth count out back.
R.E.A.R
Need to keep ground clearance in mind when going with a large tooth count out back.
R.E.A.R
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- Posts: 1685
- Joined: Fri Jun 15, 2007 7:59 am
Re: need help on sprocket
Bob is right. Smaller rear tires is like adding teeth to the bottom gear. Back in "the day", I typically ran 4" Go Power magnesium rear wheels with the smallest diameter 10" tires I could find. This was with a modified, high revving stroked Mc10 on alky. The combo worked very well. Even my Pop, who weighed 260, ran the 10" rear tires in A Super Heavy class. We also learned that short tracks liked the narrow rear slicks on the lightest rear rims we had in the shop. Rubber weighs more than magnesium does. I admit, we were running direct drive back then, so no clutch meant lower rotating mass, smaller brakes relied on the direct drive to help slow us down. The Go Kart 800 and the next year, the 1200 did not hurt either. They went where you wanted them to go with far less steering effort than our previous Bug Wasps did. TJ