Jetting for unported 4mill cub

[bansheeboy44]

I just picked up an unported 4mill cub on Friday. The cylinders had the casting flaws cleaned up as well as cases matched. It has a cool head w/ 20 cc domes, vforce 3's, 35mm carbs, advanced timing +5, and running 110.

 

I believe he said the mains were at 165 (will be riding in Glamis/Gordons) - does this sound about right? I don't recall what he said about the needle, pilot jet, or the fuel screw. I've only rode it up and down my street, but feels a little hesitant on the bottom end, only idles for a few secs, but feels real good on the top end.

 

Any suggestions would be appreciated. Just got back in the 2 stroke game and lovin' life already!!

[Darthwall]

main thing is look at the elevation where you got it from and the elevation where you are goingto use it at if you dont change anything it will be easier

[bansheeboy44]

main thing is look at the elevation where you got it from and the elevation where you are goingto use it at if you dont change anything it will be easier

 

 

The seller was in the Phoenix area and I am as well. It is 105 and humid right now compared to dune season, but just trying to make sure i'm in the right ball park.

 

Thanks

[okbeast]

I run 155 main, 48 pilot, CEL needle on the middle clip. This is at 1000 ft. of elevation and hot riding temps. Same motor and carbs.

[sleeper06]

I built the same set-up for a good friend with shearer inframes.I jetted in the winter 162 main,50 pilot,cel4th clip.Could have used a smaller pilot but bottom doesnt affect us much

[bansheeboy44]

I run 155 main, 48 pilot, CEL needle on the middle clip. This is at 1000 ft. of elevation and hot riding temps. Same motor and carbs.

 

 

I checked w/ the previous owner and he set them up at 155 so sounds like i'm in the right area- Thanks for the info

[RadarRacing]

If you've never owned a cub it may seem "hesitant" just from not revving it. That's a high rpm screamin machine. Keep it doin 8000 rpms or more and hang on.

[dajogejr]

I run 155 main, 48 pilot, CEL needle on the middle clip. This is at 1000 ft. of elevation and hot riding temps. Same motor and carbs.

 

That's where I ended up on mine, might have been 152 main... And where I rode was sea level to about 800 feet.

[bansheeboy44]

If you've never owned a cub it may seem "hesitant" just from not revving it. That's a high rpm screamin machine. Keep it doin 8000 rpms or more and hang on.

 

Thanks for the advice as that makes a ton of sense.

[bansheeboy44]

That's where I ended up on mine, might have been 152 main... And where I rode was sea level to about 800 feet.

 

 

Sounds like the consensus. 2 1/2 turns on the idle screw sounds about right?

[dajogejr]

The way I've always initially set my idle screws are by looking at the back of the carb, once the idle screw makes contact I turn it in another 1.0 to 1.5 turns in.

Hard to set the idle when you have to set the air screw first....but that's a pretty safe setting.