Box Stock

Predator 212 with a predator 420 carb

T

Tmac

New member
I know I can put this 420 carb on a 212 but does anybody know what jets I need to go with or what jets are in the carb now. Will this hurt the motor? I'm new at this. Any advice would be helpful, thanks
 
You will need some form of an adapter to get the 420 carb to bolt up. You will probably need a .037 to .040 main jet. No idea what's in it now. Barry with Youngengines will be a much better source of info than I on this. He has done this very thing many many times. Will it "hurt" the engine? No. But if its way too lean it may but that's with any carb. It may turn more rpm with the bigger carb also because of better flow. JMO Good luck.
 
Anyone know if this carb will do any damage to my motor with this carb on? I have heard good and bad?
 
Wat is done to your motor now? Running it on gas or alky? It shouldn't hurt your motor at all. It can make it better but have been told it can have a stumble if ran on gas.
 
The question I have is nrracing said for gas use 110, alky 160 and pilot .29
Anymore thoughts on this?
 
Tmac said:
The question I have is nrracing said for gas use 110, alky 160 and pilot .29
Anymore thoughts on this?
Click to expand...

A 110 is 1.1mm ÷ 25.4= .043"
A 160 is 1.6mm ÷ 25.4= 063"
I assume .29 was meant to be. 029"

Sounds reasonable. E-tube and other areas can effect jetting tho.
 
You may need to bump the timing up about 8deg to get the full benefit of alky but you will love the power increase. I see you have already upped compression shaving the head. About a 10% kick in the pants is fun...
 
Tmac said:
So do u think these numbers sound right for the jets?
Click to expand...

I think a .063 main and a .029 pilot(low) would be a good starting point for alky. Some run much larger pilots. When the engine is warmed up, if you have a stumble when you quickly hit the throttle, you need a larger pilot.
It's easy to open it on up but, I've had very little luck running the drill backwards to put it back in. :)
 
On a stock untouch carb and Etube... In our area...
A .035-.040 pilot and a .065-.068 for alky is a good place to start...
 
:confused:
Yakattack said:
On a stock untouch carb and Etube... In our area...
A .035-.040 pilot and a .065-.068 for alky is a good place to start...
Click to expand...

It's a good thing Al isn't here to give us percentages. Lol.
I bought an alky 390 carb and intake from EC. It had a .063" main and believe it or not a .024" pilot. Yeah, they had probably done some work behind the welch plug and I ended up opening the pilot to. 029".
.063 or. 065 baring Al percentages doesn't concern me that much. Alky is very forgiving on over rich. I just thought he could sneak up on the pilot size safely by observing throttle response without going over rich and loading up, fouling plugs, etc. I respect you Yak. There are just so many unknown variables. To the OP. A temp gage is your friend for safety. Take Care.
 
Yeah, and area/elevation also...
Oh don't forget air density!!!

I have tuned mainly just stock Honda 390 carbs...
I use my temp gauge on the track... And my afr/temp/rpm gauge at home on the dyno...

A good friend and fellow racer of mine runs a Young 390 carb and runs very close jetting to mine...
But DAMM that Young carb is something else...
 
You must log in or register to reply here.
Back
Top