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Messages - Knoot

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Kohler Engines / Re: Stock engine RPMs
« on: April 25, 2021, 09:02:29 pm »
I think you saw my post, kudos for being able to give the guy better information than me, I don't know a bunch about those hydrostatic setups.

Thing is, you might be able to spin a honda engine that fast, but if you spin a B&S OHV at 5000 rpm, well lets say you're going to become very familiar with the internals very quickly. I've seen people blow up stock B&S engines in otherwise great shape even at 4000rpm. See https://www.youtube.com/watch?v=H3WUKBLJsF4

I wouldn't tell people to rev their briggs over 5000 rpm  :worried: at the very least they're going to have to buy a new engine, at the worst someone could get serious injuries when the rod decides to take a trip through the block and into their face.



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Driveline / Re: Getting speed out of Drive Shaft Mowers?
« on: April 13, 2021, 01:54:45 am »
Others may be more helpful, but i'll try and answer.

Larger tires will help very marginally as far as speeding it up. If it's going 5 MPH right now, oversized tires might get you to 7mph. Removing the govenor is also a pretty bad idea on stock internals, these engines are meant to be run at 3600RPM. 3800RPM is probably safe, but anything over that is tempting fate, it also wouldn't get you that much more speed.

To get any real speed increase you either need to do one of these 4 things

1: Use a static gearbox to increase the rpm before the main gearbox on the mower. Downsides is that it'll be expensive, and reliability is a concern when you spin stock gearboxes much faster than they're originally designed to. This is a bad option unless you already have the parts readily avalible and you're comfortable designing, welding and fabbing parts.

2: Swap out the gearing on the original gearbox. Upsides is that it'll be a LOT cheaper, but finding the right parts and understanding the stock gearbox might be a little bit of a pain. I've never done this, but it's probably your best option, especially if you don't have a welder, shop equipment, and the knowhow to fab your own parts.

3: Buy a racing mower gearbox and fit it. Peerless gearboxes are the standard as far as I can see and come with the nice option of simply swapping pulley sizes to increase or decrease top speed. These are strong, but expensive, and you'll have to be comfortable with fabbing it in somehow. If you can do this, it's the performance but it won't be easy or cheap.



My advice, sell your honda. If it's in good condition it will get enough for a mower that you can more easily build. Look through the fourms for other builds for refrence. Anything with a decent transaxle and a belt pulley system can go 15-25mph for free with a pulley swap (front/back), or if you have to get new pulleys, they're readily avalible for under 20$.

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Driveline / How fast can I spin a stock craftsman transaxle?
« on: March 24, 2021, 12:11:02 am »
I have what I believe is a DANA 4360-140 transaxle, with the stock 3.5 inch pulley in the front, and a 3 incher in the back. It's going around 14mph with the current setup, but I'd like to swap to a 5.5 in the front, and a 2.05 in the back, which works out to roughly 35mph. Thing is, I know the stock transaxle isn't meant to go 9000rpm, but it's already going about 3 times as fast as stock.

Will the stock transaxle hold up? Is there anything I need to do to make it tougher?

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Newcomers / Craftsman riding mower with B&S 287707
« on: March 01, 2021, 01:02:00 am »
Hello everyone, i'm new here but i've seen lots of lawnmower racing and I want in!

My donor mower is an old craftsman with a 6 speed and a B&S 287707 14.5hp engine. I got the engine in working shape, and dropped the mower deck. I switched the transaxle pulley from a 9 incher to a 3 incher, and tuned up the brakes on the thing.

I'd like to know where to go from here, the engine def still needs some work (I can handle), but I want to make the transaxle as solid as possible before I run it super fast. Where should I start with this mower? How can I upgrade the brakes, and get the throttle mounted somewhere better?

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