Breaking in new cam and piston/sleeve?

[PismoLocal]

So i decided to rebuild my motor its a 2003 400ex motor that i bought with a 440kit installed already. I bought a stage 2 hot cam and a nem piston / sleeve and gastkets from wiseco and i was wondering how i should jet and break in the motor.

how can i jet for the cam and break it in at the same time?

[tazman7]

Just get on it and go---

Try searching. works everytime

[GPracer2500]

If you were jetted correctly before than I'd just go a little richer in case the cam wants things a little richer. If it does it shouldn't be much though--I'd guess 2 sizes tops.

[PismoLocal]

I forgot to mention im going from stock compression to 10.8:1 how will that effect my jetting?

[GPracer2500]

Originally posted by PismoLocal
I forgot to mention im going from stock compression to 10.8:1 how will that effect my jetting?

Compression changes typically have zero affect on jetting. The same amount of air is going in and out of the engine so jetting doesn't change.

[PismoLocal]

Sweet thanks for the info that was my main concern.

[underpowered]

Originally posted by GPracer2500
Compression changes typically have zero affect on jetting. The same amount of air is going in and out of the engine so jetting doesn't change.

higher compression usually requires richer jetting, mainly due to teh heat created by the compression. up 1 size max, could possibly get away with a needle clip change.

[GPracer2500]

Originally posted by underpowered
higher compression usually requires richer jetting, mainly due to teh heat created by the compression. up 1 size max, could possibly get away with a needle clip change.

I'm open to learning new things, BUT pending stong evidence I'm gonna have to disagree about that. I'm not following your logic.

If you're jetted correctly before the compression change, you'll be jetted correctly after the change. The only caveat is the high octane fuel requirement for higher compression may jet differently. But then you're jetting for a fuel type change, not a compression change.

All other things being equal, if anything higher compression requires leaner jetting (but the difference would be very small). More engine heat = a less dense intake charge = the need for leaner jets. And more importantly, higher compression promotes a more effecient (i.e. complete) fuel burn so less fuel is needed to maintain the proper air/fuel ratio.

If this is wrong for some reason I want to know about it...