Cant figure it out

[Lquad71]

Ive got my hands on a 2008 yfz450 and I just put in some hot cams stage 1 that they claim to have more mid to top end.

Mods are:
Two brothers slip on
K&n filter with outerware

Problem:popping like mad, shooting flames, I think its lean but it just sounds horrible.

Im at 1800 ft in southern ca
Main, Ive tried 168-182 and nothing, but it runs horrible from bottom of throttle all the way up.
Pilot is 45.
Needle says nfpr on it. Idk if it is stock but I would assume so. Ive tried it on the 3rd, 4th, and 5th position.

fuel screw I have tried from 1.5 turns out to 3 turns out.

I have also tried every time i fired it up to see if it makes a significant difference with the airbox lid on or off and it still runs horrible either way.

I would like to jet it for a slip on two brothers, k&n, no airbox, and some hotcams. It doesnt seem like it should be that hard. This is the first yamaha I have tried jetting btw, im used to hondas so sorry if im ignorant to some certain parts specific to yamaha.

[jjyfz]

are you sure you got it back in time right? because if you put that many diff jets in and i didnt change anything you have other problems. did it run fine before the cams? because hot cams really dont change much on a yfz runing wise. just moves the power instead of adding power.

[Lquad71]

It was running crappy before the cams went in, and yes the timing is correct. For these hotcams it is 13 links between the top dots because on the exhaust cam the dot it moved over one tooth. It had me puzzled for awhile until I looked at both exhaust cams next to each other and realized that. I just got in touch with the owner and he said it was running bad right after he put on the pipe. When I got it the bike had a 170 main, 45 pilot, 4th clip stock needle and a closed airbox. And A LOT of sand in the intake. But not in the carberator or in the head. Could pitted valves be the cause of this?

[jjyfz]

yea sand will eat up valves quick! and if the valves arent sealing it wont run good with any jets lol. how does it start? because most times if the valves arent sealing it wont start worth a crap! best thing to do is a leak down test. oh and did you check the valve clearance when you put the new cams in?

[Lquad71]

I adjusted the valves, they werent too far out of spec but they were adjusted before the cams went in. The bike starts up quickly and i have gotten it to idle but doesnt like throttle. Im going to try throwing on the stock exhaust and rejet back to stock. This isnt my bike so i dont have the manual, can anyone tell me what stock jetting is for a 2008? Thanks.

[Lquad71]

changed a few things around and now it runs well with the choke on but with it off it still backfires. Does the choke on these add fuel or restrict air? If i can get it to run like it does with the choke on it will be good but I dont know what I should change. 45 pilot, 170 main, 2 turns out, 4th clip on stock needle.

[jjyfz]

the choke adds fuel. bump the pilot jet to 48 and about 2 turns out on a/f screw see it that helps. and is that 4 clips on the needle from the big end? the closer the clip is to the big end the leaner it is

[Lquad71]

Got it figured out! that 48 pilot with the zip tie mod, 2.5 turns out and 4th clip from the top. runs great.
Thanks for the help guys.