Go Kart Project

Posted: Wed Dec 06, 2017 6:23 am

So this isn't 'F related at all, but we're all gear heads to a point. I recently got an old, broken industrial walk behind lawn mower. It's got many of the little bits needed to make a go-kart. The engine is a kawasaki fh451v. That has OHV 494cc, aluminum block, cast iron sleeves and full pressure lube. Rated power is only 15hp @ 3600rpm.
I'm making off the cuff assumptions here, but it seems the engine could easily do 30hp if not more. Where would you guys start looking to beef up an engine like this. Just looking for ideas since I got this for free'99 and would like to do something with it.

Posted: Wed Dec 06, 2017 5:14 pm

Its all in the intake, compression and exhaust. I'm not being flippant but factual as these areas are where your answer resides.

Captain

Posted: Wed Dec 06, 2017 5:28 pm

Thanks Captain. Honestly I'm quite new to those areas. I would think tuning the exhaust to maximize cylinder evacuation at particular rpm ranges, and also maximize flow on both sides. My rudimentary understanding on increasing compression would look towards raising piston crown, and lowering combustion chamber perhaps just by skimming down the squish area. Am I on the right track here?

I have a real concern about this as I don't know if the rods, Pistons, bearings, etc can handle higher rpms or even the added stress of more compression and power.

Posted: Wed Dec 06, 2017 5:47 pm

15 HP is quite a bit for a regular go-cart. Open up the exhaust ,,,

Posted: Wed Dec 06, 2017 6:34 pm

dannewman wrote:

15 HP is quite a bit for a regular go-cart. Open up the exhaust ,,,

You might be a wise voice of reason. I probably don't "need" more power, but I want it.

Posted: Wed Dec 06, 2017 9:27 pm

If some power is good,
Then more is better,
And to much is just right!

Posted: Thu Dec 07, 2017 12:21 am

We've had em' here with snowmobile motors. Scary with the wrong driver. One rolled five times,,,

Posted: Thu Dec 07, 2017 7:02 am

is it a single carb to twin branch manifold with the carb governor controlled ? - recon swapping this lot out for a twin carb direct lift - TBH just manually op versus governor will add some vavavavoom
check if its got steel or alloy rods - if its like a briggs n stratton - alloy rod then rpm is limited before they snap - recon you'll still manage another 1000rpm
probably find a wee bit via ignition timing

Posted: Thu Dec 07, 2017 2:50 pm

Quote:

is it a single carb to twin branch manifold with the carb governor controlled ?

That's exactly the setup. I had the thought to try some rs36's, but I don't have that kind of cash.
Question

What if I put Mikuni's on my F, then put two of those CV's on the kart? I'm sure that'd be a joy to tune. Razz

Quote:

check if its got steel or alloy rods

Thanks for that advice!

Posted: Thu Dec 07, 2017 5:26 pm

couple of small direct lift carbs from yir local bike breaker from something old and forgotten
but 1st off see if you can tweak the governor - i.e. bend it

Posted: Thu Dec 07, 2017 7:48 pm

Techie66, I have a set of carbs from an old SOHC bike. No idea what bike or anything like that and they are all apart in pieces and filty...but they're yours if you want them!

Set of 4, maybe complete, maybe not. PM me if you want them.

Posted: Fri Dec 08, 2017 12:33 am

Put a turbo on it! I just read a book on turbocharging and have had it on my mind lately. You could probably leave the motor stock and put up to 7 psi on it, which would boost power a good 20-30%. Beyond 10 psi and you'll have to start changing the engine. Turbos for small engines are not priced too high.

https://www.dhgate.com/product/hot-selling-diy-turbo-500-turbo-kit-motorcycle/214174143.html?u

http://www.ecotrons.com/products/small_engine_rhb31_vz21_turbocharger/

Posted: Fri Dec 08, 2017 12:57 am

The small dragsters running a 5 hp Briggs & Statton base block have produced around 19hp. some good ideas right there,,,

Posted: Mon Dec 11, 2017 1:58 am

A 50 shot of Nitrous would be fun as hell for a solid 10-15 seconds...

Posted: Wed Dec 13, 2017 12:39 pm

you can also check your gearing many years ago when I rode gokarts around the neighborhood I played with the gear ratio to get more top end vs a quicker take off.