Our Yerf 3202

mstiebel

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I picked up a yerf dog 3202 frame without a rear swing arm or anything that attaches to it. I have a GX390 from an old pressure washer, so that is going to be the center piece. I'm starting to assemble the shopping list:

Swing arm - I'm waiting on BMI (https://www.bmikarts.com/Swing-Arm-for-Go-Kart_p_1877.html) to respond to an email whether they can a) leave the swing arm mounting brackets off, and b) they can weld in some threaded bungs for heim joins. I figure, since they're made to order, there's no harm in asking the question. Any thoughts to add?

Torque Converter/Clutch - I'm looking at the OMB 40 series (https://www.ombwarehouse.com/40-series-1-torque-converter-with-steel-mounting-plate.html). The Gopower just seems too exspensive. With the OMB torque converter kit, the jack-shaft is built into the kit, correct? Therefore I can omit the Yerf Dog factory jack-shaft plate, right?

Rear Axle - I haven't even scratched the surface on this one. I'm seeing some kits, but I haven't compared to see if the bearing mounting points are standardized across all vendors and kart frames. I would love to find something with a continuous keyway, disc brakes, bearings, etc. all in one package so I don't have to keep hunting around (and worry about missing something). Is 45" the right length?

Shocks - I'm planning to replace the springy things with actual pressurized shocks.

Anybody have a recommendation on axle sprocket and wheel sizes for this engine/kart combo?

My apologies if this is all covered somewhere already, my spare minutes are short. Any advice is greatly appreciated!
 

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Hellion

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Glad they have measurements on it (Swing Arm for Go Kart For Yerf-dog Go Karts Number: 05303):


Screenshot 2026-08-23 at 6.19.01 PM.jpeg

For me, I would be looking to re-create the kart as it was from the factory. A complete (as is feasible) mechanical restoration.

Q43200W Torque Converter Driven
Q43201W Torque Converter Driver
Edited to add: that’s a 30 series “divorced unit” (no plate) but won‘t work with your larger 390 engine.

03191 Clutch mount assembly

The front and rear rims appear to be 6” and 8” respectively. I plugged in the (all these) part numbers on BMI and they come up.

15 x 6.00-6​

20 x 10.00-8​



Will let the forum weigh in on the particulars.
 
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Hellion

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I would shop around elsewhere for tires as they are pretty universal. Fleabay, Amazon, Walmart has been good for tires at good prices.

Edited to add: the original sprockets were 10 and 60 tooth.
H92541W SPROCKET, 10 TOOTH
23001100 SPROCKET, 60 TOOTH

That’s a good gear ratio. You can plug those numbers into BMI product search.
 
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panchothedog

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You need a 40 series torque converter for the 390 engine. I bought my 40 series at
OMB Warehouse, the plate version. Have used it on a built 301 as well as a built 420.
Very happy with it. Not one single problem. Plus they include the reverse wound spring in the setup. Good product.
 

Hellion

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You need a 40 series torque converter for the 390 engine. I bought my 40 series at
OMB Warehouse, the plate version.

So the plate version 40 series is okay for his application? I wasn’t sure on that and was worried about the fit geometry but it would save on parts count/complexity.

Reposting his link for consideration: https://www.ombwarehouse.com/40-series-1-torque-converter-with-steel-mounting-plate.html I guess it’s the same one you bought, Pancho?
 
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