Replacement Head Suggestion

[blockdoc]

Hey guys,
I've read a ton of threads but thought I would just ask outright.

Over the summer, my son and I built up a predator motor for his (and mine lol) minibike. We have been running a 14cc head which my son ported and polished, stock sizestainless steel valves, Mod2 cam, Arc Rod, 1.3 intake rocker arm, etc. We have a dished piston, which is about 0.2 in hole with standard length arc rod.
He apparently had bolted a header support onto the head.....which broke off.......and took a corner of the cast off at the valve cover area.

Here's my question...
Im too lazy to port another head and want to try something different...

1. If we order a ported 18cc head from NR Racing, how much would ya'll suggest I have it milled (using pump gas)
.050 or .065 (or does it really matter?)

2. Is there any advantage or disadvantage of 27mm Intake/24mm Ex vs 27mm and 25mm Exhaust valve sizes?

3. We currently have the Honda Carb 0.625. Its been great. Is that appropriate for the above setup?

He doesn't race this bike, and does value torque over top speed if we have to choose. We have a GTC TAV which has held up great with his 150lb frame

Appreciate any suggestions

Brian

 

[bdomit01]

I would stick with the 24mm exhaust with a 27mm intake. If you're were going to jump up to. 28.5 intake I would say get the 25 exhaust.

If you're sticking with a .625 carb though I would just stick with the stock die valves. If you're going up in valve size though a carb in the range of 22-24mm should do nice.

 

[blockdoc]

I would stick with the 24mm exhaust with a 27mm intake. If you're were going to jump up to. 28.5 intake I would say get the 25 exhaust.

If you're sticking with a .625 carb though I would just stick with the stock die valves. If you're going up in valve size though a carb in the range of 22-24mm should do nice.

Thanks for the input. I did in fact end up ordering the 18cc ported head with the 27/24 valves, it was milled .050. Ill keep the .625 carb for now since we kind of value midrange torque over top speed for our application.

Cheers