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Old 03-28-2020, 04:21 PM
Mack2 Mack2 is offline
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Default Torque Converter Help

First post... Thanks for reading

I am building my son his first kart, also my first kart build... but not my first build.

I have an old Briggs 3hp with a straight threaded 5/8 output. I have the motor apart and was planning on milling a keyway and tapping the end... however I'm having a hard time finding a 5/8 drive torque converter, do they exist, or am I stuck with a clutch? Also, the motor has never been used and its first run was earlier today, It was also free so I'd like to avoid the predator and a cheesiness 3/4 drive converter route.

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Old 03-28-2020, 04:30 PM
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Well eBay would be your best bet for a 5/8th drive torque converter or you can make it with pulleys and a foot belt engage like a manual clutch like tillers use. I was planning on doing it with a mini bike at one point
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Old 03-28-2020, 04:48 PM
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I looked on ebay and couldn't find a 5/8 drive only driven?

---------- Post added at 06:40 PM ---------- Previous post was at 06:37 PM ----------

I was also considering turning the 5/8 down and making a 3/4 sleeve that I could weld on. Will the 3 hp have enough to run the 30 series converter?

---------- Post added at 06:48 PM ---------- Previous post was at 06:40 PM ----------

the bearing race is .785, so I can squeeze a 3/4 sleeve in there

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Old 03-28-2020, 07:12 PM
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I'd recommend against welding the sleeve to the crankshaft, it will ruin the hardening of the steel. You can get a 5/8-3/4" sleeve (with stepped key) on Amazon and other places im sure. If you cut/trim/fit it well, torque the crankshaft bolt and use threadlocker you should be fine in my opinion (pending you turn and tap it as mentioned).

I dont have any experience with 3hp with a torque converter but from what I gather, a clutch and a tall(er) gear ratio would work best.... but I could be wrong. What tire size (height) are you thinking of running?
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Old 03-28-2020, 09:42 PM
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You could probably just use a slip fit spacer.
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Old 03-30-2020, 05:59 AM
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After sleeping on it, think I'll just go with a clutch as he'll grow out of it pretty quick. I milled a keyway and drilled/tapped for bolt, got it back together and it's ready to rock!

Can you all reccomend a resource for figuring out tire size and gear ratios? I've purchased an 11 tooth cluth so that's where I'll be starting. Thanks for the help
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Old 03-31-2020, 08:24 AM
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A really great live app for that is at : app.kartcalc.net It takes weight, gearing and tire size (height) into account, tells you approximate top speed and any issues you may run into.
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