[san210crf250]

I have done the following on the 06 250X at 6000 ft elev 50 degrees or so:

JD Jet Kit
Redneedle 5th down
160 Main 42 Pilot
Boysen Accelerator Pump Cover
Cut 4x4 hole in top of airbox
Twin Air Powerup kit
Drilled exhaust baffle

Problem:
Idle is rough and surges to a higher RPM about every 3-5 seconds and when it does I get a real loud popping sound from the airbox, and then back to the idle and popping goes away, the popping is not from the exhaust it is echoing through the air box intake. Bike was fully warmed up and seems to perform well when riding through all of the gears and rpms. Any suggestions? Thank you.

[san210crf250]

oh yeah fuel screw is 2 turns out.

[Asmith]

Check for airleaks at the boots connecting the carb to the airbox and head. Spray carb cleaner on them and see if rpms increase.

[san210crf250]

I will try the carb cleaner... Looks like I didnt do the "O" ring mod for some reason I assumed that the "O" ring mod was replacing the O rings in the stock accelerator cover so I didnt read through it carefully enough. Could this affect the problem and how important is it to do this "O" ring mod? Thanks.

[Asmith]

It is important, but does not affect Idle. It affects off-idle bog.

Do it.

[san210crf250]

Hey Agent, the JD instruction's picture of the O ring location is pretty low resolution do you know if there is a sticky or a good photo of what to do on this mod? I have done quite a bit of searching and haven't found much on it. I am kinda bummed because I will probably have to tear the carb out again to get to the O ring location, it looks like. Thanks.

[san210crf250]

I did some more digging and found it...

http://www.squadpage.com/pandora/Profes ... %20Mod.pdf

thanks again agent!

[Asmith]

It's also in our sticky's:

http://www.crfsonly.com/forum/viewtopic.php?t=13500

[san210crf250]

So I forgot to do the "O" ring while I had the bike torn apart so I did the tear down all over again but it was worth it. I retraced my steps and replaced the 160 Jet with the 165, pulled off the Boyeson AP and inspect reinstall. It runs like a champ now, I even got the "Siren" pull over right in front of my house this morn while test driving it (I dont have my Lic plate yet) just a paper temporary. Thanks all for your great posts!

[NCLR1]

Glad to hear everything is running well now. It seems you still couldn't narrow down what the original problem was. I would like to echo what AS said about your problem with the reving every 3-5 seconds. That is a clear sign that you have an air leak. Possibly from a hose that was not reconnected after your first install. I always have an issue fitting the air box boot back on the carb. It likes to fold up and is hard to see the entire thing.

[Monkeywrench]

Little trick to getting the carb boot back on: take some liquid cleaner (your choice) and apply some to the inner rim/surface of the boot. While pushing down on the subframe with your right hand, force the boot to stay stright with your left hand, and the cleaner will help the boot to slip on the carb a little easier.

I have found cleaner works better than striaght water, becuase it has a way of feeling "slimier" to the touch than water.

[NCLR1]

Thanks for the tip. I find that it helps to not forget to pull down on the little tip that is on the bottom of the boot.