hotcam users, what jetting?

[cals400ex]

i am getting ready to jet my bike for my new stage 2 and 10.8 piston and was just wondering what you were all using? in other words, how much bigger did you have to go on the jets from before you put the cam/piston in versus after you put the cam/piston in? thanks

[zlam27]

sorry cal, you help so many and no one can help you. anyway, not to hijack your thread but i had a question for ya.....

with my 400 (mods in my sig), im running a 158 main and 42 pilot. it sputters on decel (backfired once), starts kinda hard, and the throttle response is horrible. i backed that screw out so i can see about 4 threads all the way around. i know i must be lean if it backfires and pops like that. should i go to a 40 pilot (could turn the fuel screw out only 1 or 3/4 turns to lean up that circuit). i think im gonna throw the 160 dynojet back in there even though i dont have the needle (throttle response was great). im gonna pull the plug today and see what it looks like. i hope eveything works out good, if you have any comments or suggestions just let me know. thanks a bunch.

zach

[Martin Blair]

first of all for you hotcam and piston i would go up 2 sizes on your pilot, got raise the needle up a clip ( actually moving clip down), and go up 5 sizes on the main, say if you where runing a 40 pilot go to a 42, if you where at stock needle go to 4th clip and if you where running a 155 go to a 160 for starters.

Zlam going froma 42 - a 40 would be leaning it out more, try a 45, even thought a 42 should be fine, maybe try moving you needle clip to the 4th position.

[YZROOSTINYA]

155 main
45 pilot
4th clip down on needle
2.5 - 3 turns out

sig for mods

[cals400ex]

Roost, a 155 main seems small. however, you know more than me so your probally right. i am running a 160 main right now without a built engine. i have x-6 exhaust, no lid, uni filter, and no choke. sparks claims i am too big on the mainjet but mine runs the quickest with this one in. i race my friend with each mainjet in and it seems to run the best with the 160. i would think that a 160 is too big but if thats how it is the quickest, i will leave it there. i am already running a 45 pilot, that is what sparks said too run and it seems to start and idle just fine. my needle is in the stock location.

zlam, go ahead and try a bigger main. i would put money that your in the ball park. with 4 threads out on the needle jet holder, you should be good to go there. i would leave the 42 pilot in place. how many turns out on the fuel skrew are you? let us know how the plug looks even though the fuel additives may give false readings. like mentioned above, you could also try to move the clip on the needle in the 4th position. the needle in the 4th position worked excellent for me with a 42 pilot in place in the winter months. i now moved on to a 45 pilot and the needle is in the factory position.