Hey guys...Here I am once again asking for help.....But your so nice!

Anyway..I need some basic advice that hopefully you can give me real quick....As you know I've been redoing my 07 crf450r and have put in a 13.5 high compression piston, hotcams stage two cam and stock head. My question is what would be a good starting point for my jets in my carb? Does the high compression piston affect my pilot or main size? Does the cam? I have 100ll gas and I know that will lean it out a little, but feel the cheap price of it and it's convenience (right next door) make it worthwhile to run, I also know the lead has to help valve life. When I started it, it was hard to start and wouldn't idle without the choke on and the throttle stop screw in to about 3500 rpms..which I know is way too high, and it would rev up and down a little and crackle and pop. Pulled the plug, it was grey, so it's lean, and then took the carb apart to clean out the carb and noticed the needle had a red top which I am sure is a jd jetting needle, which is I think the high altitude one...I live at about 700ft above sea lvl so....I ordered a stock needle and some jets both up and down for both pilot and main. Hoping the needle made the huge difference, and with the stock one it will be much better. Bike had a big bore kit previously, so the jets are 42 pilot which I know is stock and 190 main which is prolly too big (178 stock). So...where should I start? Got a week or so till jets show up.....will let you know how it goes...Thanks in advance guys you are awesome.

45 pilot 165 main would be right for pump gas. Pure avgas is not the cure all that one would think, but for a 13.5 motor, I would run 30% avgas mixed with premium pump gas.

start at stock jetting. The needle will not cause idle issues.

more than likely the hotstart plunger is not fully seated into the carb bore (needs cleaned, lightly greased and cable adjusted so there is slack) and pilot is plugged up. Those are the 2 common causes of idle issues. Lastly check the slide plate is not inserted upside down.

If youre going away from the JD jetting, go with the stock needle too. The reason is that the JD needles are so big at the end that they actually impede the main even at full throttle. Hence the giant jet.

With the piston and cam and all that, they seem to react better with the OEM needles. Although, the 13.5:1 piston seems like it'll want a bigger jet, start with the 42 which is stock.

The Stage two cam is similar to the 02 cam which seems to want a larger main jet, but not huge. Starting with the 178 main, a 42 pilot and the OEM needle in the middle should get you to where the thing should run more normally. Start the fuel screw at 2 out with the AV gas.

The plug being gray isnt bad on a thumper. Remember, its thumper. There isnt any oil in the fuel. Also, pump gas burns like shit and will almost always give you a dark brown almost black plug anyway.

Thanks guys, you are great.

Update: I think the main jet was a little clogged...or the passage way...plus I learned I NEED to use the hotstart lever to start it hot.....I also raised the float level so it may have been too low...but it does want the bigger pilot and smaller main I think. Again thanks guys for the help, and I love my new to me 450r....so easy to ride...I can't wait to go riding! And the suspension id perfect...but I don't think it is stock.

The reason you NEED to use the hotstart is its probably too rich. The hot start circuit is just an air way around the slide that doesnt pull fuel when you kick it. The hotstart is an option to try to dry it out when its hot and maybe went upside down or something. When youve got the jetting right, you wont need the hotstart even when its hot.

Thanks Shawn! I adjusted the fuel screw out until it quit revving up and down at idle...... and idled smooth....At that point it was out like 3 or 4 turns....figured I needed a bigger pilot...like what was suggested...what do you think? Is that high altitude needle screwing with me? should I raise the clip a notch?Idle is the only symptom I had...starts first kick with the hotstart in. Just reread your post...I haven't got the factory needle yet will come this week...maybe I should just wait for it and mess with it then. Thank you Shawn....your awesome...I will keep you informed...and coming from smokers, these four strokes are almost cheating...so smooth...I love it.

At 3 or 4 turns out, the needle will fall out while riding. Trust me on that. Was the engine hot when you did this? (made the adjustments)

If its happier at 4 out, go ahead and try the 45. But if the engine isnt HOT when youre attempting all this stuff youre just pissing in the wind. You shouldnt need any altitude adjustments unless its super hot out, hot and humid out, or at altititude.

If youve got the altitude needle in there and its in the 50's, its probably going to be lean a little.

When you get the stock needle, put a 180 main jet in there and the 45 pilot, start at 2 out on the fuel screw and see where you end up. If youre running the AV gas, it'll probably be a tad rich simply because of that. The Ethanol in pump gas causes them to act a tad lean even when they soot up the plug.

Sounds great sir, I will let you know next week how it went.

Got it running great today....thought I'd letr you all know..42 pilot and 178 main was perfect. Thanks so much Shawn and all you guys you are a big help.