6.5hp Kohler performance parts, or new Predator engine?

[tomdowns]

I am returning to the beautiful world of Go Karts with much newfound cash, but obviously wanting bang for buck. The kart comes with a 6.5hp Kohler engine. For the longest time I had my mind set on a brand new Honda GX390 (http://fayar.craigslist.org/for/3811329971.html if you're interested) for $500 but after doing a little research I realized I might not need the extra displacement and the 1" shaft would require me to get a different pulley for the torque converter, and that might not be cost efficient for what my interests are. I want a kart that can blast down dirt roads and handle some bumps, but can still perform on the street. General purpose.
I was thinking about either
-sticking with Kohler engine and doing mods
or
-buying a new 6.5hp predator from harbor freight

My reason for wanting the predator is that all honda parts are interchangeable, and most small engine performance parts seem to be honda parts.

My reason for not wanting to stick with the Kohler is that I have been unable to find any performance parts for hopping up the engine.
Thoughts?

Also, I did a speed calc online for my kart I plan to purchase, but it came out with 16mph. The current owner told me "81 tooth two piece sprocket on bottom and 10 teeth on top" I assume these sprockets are all after the torque converter. The engine undoubtably runs at 3600rpm and I believe real wheel height is 12in. Did I do something wrong?

 

[tomdowns]

Also, is this an awesome buy for $425 or what?!

 

[gvfc2]

thats about right for the ratio. but i doubt you need that ratio on there. could go with 6:1 or 7:1. with the TC on there could go lower. im guessing the guy you bought it from used it for lot of hill climbing

 

[tomdowns]

Weird, so it probably accelerates very quickly? What is the easiest way to change ratio? Like which gear to switch out, jackshaft or axle?

 

[tomdowns]

I really need advice about which engine to go with, I want to put a header on there and a new intake. What is the next cheap engine hop up, and which engine will be easier to find parts for?

 

[buckwheat]

You have done your research correctly. The Predator engine has the aftermarket speed goodies where the Kohler has none. That kart is not going to need a lot of go fast goodies IMO.

 

[tomdowns]

Why did you say that buckwheat? I suppose there is a marked difference between need and want

 

[tomdowns]

I plan to change gear ratio to 6:1 once I get new engine and hop up kit from nrracing.com

 

[gvfc2]

might be easier to get a new axle sprocket. also IMO the predator is better. i have one on a minibike and easily does 25mph on flat with a 7:1 ratio. and its stock. if you put on a hi flow intake and exhaust might want to rejet the carb

 

[tomdowns]

I looked at the axle sprocket part and it looks like a solid sprocket, not the split type. Are they difficult to switch out?
http://www.nrracing.com/product-p/stage1hopup.htm
this is the kit I was going to purchase

Edit: Looked into it and saw that I can switch out the axle sprocket easily. I plan to get a 40t axle sprocket so the ratio is 4:1 and give me a top speed of 32mph. I hope it will accelerate there with enough speed. Do ya think it'll pull hard with the 10hp after hop up kit? is there a general rule for judging acceleration ability according to hp?

 

[Doc Sprocket]

Switching out a sprocket like that is fine, as long as the shaft and other components aren't particularly rusty. It will likely require you remove the axle from the kart.

 

[ross1998]

I looked at the axle sprocket part and it looks like a solid sprocket, not the split type. Are they difficult to switch out?
http://www.nrracing.com/product-p/stage1hopup.htm
this is the kit I was going to purchase

Edit: Looked into it and saw that I can switch out the axle sprocket easily. I plan to get a 40t axle sprocket so the ratio is 4:1 and give me a top speed of 32mph. I hope it will accelerate there with enough speed. Do ya think it'll pull hard with the 10hp after hop up kit? is there a general rule for judging acceleration ability according to hp?

4:1 is a little low, maybe 5:1?

I personally like higher gear ratio like 6:1 or even 7:1 for the sole purpose of accelerating quick and drifting/burning out/donuts/fun on snow.

 

[gvfc2]

 

[landuse]

4:1 is a little low, maybe 5:1?

I personally like higher gear ratio like 6:1 or even 7:1 for the sole purpose of accelerating quick and drifting/burning out/donuts/fun on snow.

You have got it all the wrong way around. A high gear ratio has a smaller number (eg 4:1) and a low gear ratio is a higher number (8:1)

 

[tomdowns]

^this.

It turns out the dudebro who was selling the steal-of-a-kart left for work and his so-called "wife" sold it. I even planned with him for $50 off and a deposit. NUTS. Starting my search again...

 

[landuse]

^this.

It turns out the dudebro who was selling the steal-of-a-kart left for work and his so-called "wife" sold it. I even planned with him for $50 off and a deposit. NUTS. Starting my search again...

Huh. I am confused. Was the kart not yours yet?

 

[tomdowns]

Nope, but we had completely settled on it...I'm out of town until a week from now

 

[OzFab]

I did a speed calc online for my kart I plan to purchase, but it came out with 16mph. The current owner told me "81 tooth two piece sprocket on bottom and 10 teeth on top" I assume these sprockets are all after the torque converter. The engine undoubtably runs at 3600rpm and I believe real wheel height is 12in. Did I do something wrong?

Yeah, you did. If that is a pic of the kart, those are not 12" tyres, more like 16"-18" in which case, you're looking at closer to 21-24mph. Even if that's not the actual kart, if it's something like it, the same point applies

 

[zbuck]

The Kohler XKE was strictly built as a racing engine, with plenty hop up parts available, the engine its self is no longer being produced. The new Kohler CH270 (208cc's) is the current engine, with some hop up parts which are extremely expensive. Mosty used in the F1 class of racing. You would be better off to go with the GX200/clone as the hop up parts are half the cost of the Kohler parts.