Box stock 6.5 or bone stock 13?

[Offroad Karter]

So I bought my son a Baja Blaster 65 offroad kart about a year and a ha the diversionlf ago. It was a great kart for him to learn on, but now its too slow, not enough power (especially if I'm in it), so we decided to look into upgrading the
drivetrain. I've done a ton of research, but I still have a few questions, the first being:
1) WHAT IS BETTER FOR POWER AND PERFORMANCE IN AN OFF ROAD, 2 SEATER, FAIRLY HEAVY KART, A 6.5 hp CLONE WITH A BOX STOCK UPGRADE SETUP, OR A BONE STOCK, STRAIGHT OUT OF THE STORE 13 hp?

2) SHOULD WE STICK WITH A TORQUE CONVERTOR, OR SWITCH TO A CENTRIFUGAL CLUTCH

3) SHOULD WE CHANGE THE GEARING (currently has 60 t on live axle & 10 t on engine shaft with 19 x 7-8 tires).

Any assistance would be great!

Thanks

 

[OzFab]

Welcome to the forum

Yeah, a 6.5hp isn't gonna be too exciting on that, I'd go for the 13hp.

Stick with a cvt (torque converter), however, you'll need to upgrade to a 40 series on the bigger engine. A cent clutch will reduce performance

Gearing sounds good, leave it alone

 

[Offroad Karter]

Thanks for the info, I really appreciate it! Any idea what kind of overall speed I might get with a Predator 420cc and a 40 series Torque Converter, if the cart weighs about 300-400 lbs?

 

[tha_thrasher]

Hi, i had a go kart some what like yours, mine had 20 inch atv tires with a bone stock 6.5hp with a tav, it went through the Florida sugar sand pretty well. it went a bout 30mph with 10-55 tooth gearing.

 

[landuse]

Thanks for the info, I really appreciate it! Any idea what kind of overall speed I might get with a Predator 420cc and a 40 series Torque Converter, if the cart weighs about 300-400 lbs?

That depends how you gear it.

 

[Offroad Karter]

Thats not too shabby. As it turns out, we went and bought the Predator 420, got it home, took the old engine out of the kart and proceeded to find out that the 420 was way to big to fit without major frame mods. So we took out back and exchanged it for the smaller, yet still more powerful than what we had, Predator 212. Now we gotta order the TAV unit and a few other 'hot rod' parts and I think we will be good to go.

 

[tha_thrasher]

offroad karter. The first things you should get/make is

1. air filter adapter, with filter
2.bigger jet (i use #90)
3.header
that will get you about 1 more hp
If you want to go even faster you could remove the governor,but if you do that then you will either have to get a tach or billet parts(con. rod, flywheel) and 18lbs valve springs.

 

[OzFab]

If you want to go even faster you could remove the governor,but if you do that then you will either have to get a tach or billet parts(con. rod, flywheel) and 18lbs valve springs.

Umm, NO! If you remove the governor, you don't need the billet parts unless you change the valve springs. The standard springs (10lb IIRC) will create valve bounce or flutter at around 5000rpm, preventing the engine from revving any higher &, therefore, negating the need for the billet parts.

If you use 18lb (or higher) valve springs then it's highly recommended you also use billet rod & flywheel...

 

[tha_thrasher]

Umm, NO! If you remove the governor, you don't need the billet parts unless you change the valve springs. The standard springs (10lb IIRC) will create valve bounce or flutter at around 5000rpm, preventing the engine from revving any higher &, therefore, negating the need for the billet parts.

If you use 18lb (or higher) valve springs then it's highly recommended you also use billet rod & flywheel...

Hmmmm, very interesting, because a friend of mine blew apart his flywheel witch caused a hole in the block (grey hound 6.5) after removing the governor and not changing valve springs.

 

[Offroad Karter]

Yeah, I've heard quite a bit about the good and bad of governor removal, and I think I'm of the ' wait til I have the upgraded internals team' on that one. I did however order a new comet 30 series torque converter, and next on the list is a stage 1 kit.

 

[fowler]

Hmmmm, very interesting, because a friend of mine blew apart his flywheel witch caused a hole in the block (grey hound 6.5) after removing the governor and not changing valve springs.

Yep there's always been negative vs posative

Once u look into it case by case
There's usually
In was a friend of a friend story
Or " well maybe I dropped the flywheel or hit it with a hammer
Or the favourite I knocked off find to make the flywheel lighter
Lastly it was faulty from factory

They by law have to built a buffer zone into these engines
It would be daft to build these to fail 1 rpm over 3600

Much like chains
Lifting chains are pulled till they snap
Then 1/3 of that force is the weight limit

A genuine Honda flywheel will go well past the stock
The more Chinese clone u go the more u risk
Predictors are good as far as clones
Then u get stuff like scorpions
And I won't use a stock one of those after a few close calls with there crapness including a fuel line leak from brand new
And a flywheel nut falling off

There's no real risk of removing the govner and leavening the springs
Some people are just unlucky though
And like me and scorpions u change their opinion

 

[Offroad Karter]

Thanks for the insight. All the info ya'll have given has been super helpful. I just finished finished putting a fresh coat of black paint on the lower, main body and fresh green on the currently removed roll cage section. TAV unit is scheduled to arrive on Monday so I wanted to have it all ready to go before that so all I have to do is install the unit onto the engine, and then drop the engine into the kart. Few hours of break in for the new powertrain, and finally time to test this bad boy out!

 

[OzFab]

Cool, good luck