Go kart hard string pull and slow take off

[Cesar]

I used to have a honda gx200 on my go kart but it broke down it would take off fast and go fast it had mods like removed governor upgrade 18lb springs new air filter fuel pump and exhaust. So I went to harbor freight got the 6.5 predator and did all the upgrade swaps it takes off slow kinda hesistant but once it takes off its fast and the pull string is hard my arm is killing me from it pulling back and I'm scared to pull it lol. Why could this be? I wasn't sure that to set the valve lash at since the page I looked at before with the honda is now gone so I set them both at .003

Oh yeah and the jet I use this time was slightly smaller becuase I had to break the bigger one when getting it out of old honda. Could that cause this?

---------- Post added at 01:07 PM ---------- Previous post was at 12:57 PM ----------

I'm also curious is more cc better? Becuase my gx200 was 196cc and this predator is 212cc I think

 

[Poboy kartman]

A couple of things: One, if you upgraded the cam, it may require different valve lash.

The 18 lb. springs are going to make it a little harder pull anyway.

Did you use an offset key or change flywheels?

Define the mods in detail....

 

[Cesar]

Nope same key and same fly wheel the springs were the only real internal upgrade besides govenor and carb

 

[Denny]

Cam one tooth off?

Denny

 

[Poboy kartman]

Could very well be ^.

But...oh Gawd!!!!! ANOTHER springs without rod!!!!

 

[Cesar]

Ill check it out but the cam didn't come out when I took off the side cover. What rods should I upgrade to?

 

[Poboy kartman]

A billet connecting rod....or lose those 18 lb. springs.

 

[Cesar]

Ok kart man will be buying it soon. There are different measurements. Like a 3.707, 3.625, 3.303 and quite a bit more what should I get for my predator 6.5 212cc? And what's the reason behind changing it?

 

[mckutzy]

The springs allow the motor to spin faster than the limits of what the con rod can handle.... typically..... but why chance it...

 

[bob58o]

Is it a hemi? #60363? Stock length is 3.308. I used 3.328 with slightly thinner than stock gasket. It is done to increase compression by reducing the size of the combustion chamber.

My piston sat around 0.023" below the deck before I got the new rod.

Stock gasket is like 0.040 or 0.041, but you can get as thin as 0.009

Connecting rods require a 1/4" 12 point socket and should be used with in-lb torque wrench.

ADDED: You want at least 0.030 between the piston top and the the bottom of the head.
EXAMPLE: 0.023" below deck + 0.009" gasket = 0.032" clearance
0.005" above deck + 0.036" gasket = 0.031" clearance

I was at 0.003" below deck and used the 0.036" gasket for 0.039" clearance.

 

[Cesar]

The reciep says 69730 7hp 212cc engine I only see 6.5hp engines idk if that number is good