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Old 03-27-2020, 09:25 AM
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Default Driver pulley rpm limit?

I finally found a long flat desolate road to test the top speed on my stage 2 Murray Explorer with a 30 series TAV and governor delete. It was revving quickly from 3,500 to 5,000 rpm then it just stopped revving and took a long time (probably another 1/8th mile) to go from 5,000 rpms to 5,100 rpms. I'm curious if i've found the limit of the stock driver pulley? I was thinking about getting the Juggernaut pulley since my motor is built to go to 7k+ rpm.

Also, after the last top speed run I noticed that my catch can had spewed blowby out of the top vent filter and the bottom drain and was all over the frame lol. Do I need to put O-rings around the fittings or get a better catch can? Its just the $25 catch can from GPS
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Old 03-27-2020, 09:34 AM
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Once the driver pulley has hit top ratio, you can spin it till it flies apart (which will happen eventually), but there's not really a hard "limit".

Sounds to me like your engine just hasn't got the oomph to move the kart any faster.

Of course, you're losing 20-30% of your peak power in that belt drive.
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Old 03-27-2020, 11:31 AM
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Am I losing that much power through the belt? That makes sense. It feels like it can go a bit faster if the pulleys and belt are cold. A friend of mine on here used to have a centrifugal clutch setup on the same kart and he could do almost 60 with the full cage. I know the clutch isn't good for offroad/trail riding with 18" tires.

I have a split sprocket on the way to replace my worn out 60t axle sprocket. I can adjust my gearing if needed as well
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Old 03-27-2020, 02:20 PM
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Torque converters are great when you spend a lot of time at partial throttle. No clutch slip to worry about, and the variable ratio makes up for not being in the engines power band.

For top speed, a good clutch is the way to go. Nearly 100% efficient at full lockup.

And yes, a torque converter can cost you near 30% of your total power output. Again, you tend not to notice it under acceleration and lower speeds.
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