[11ChanceWeight11]

Hey, I have a '08 250R and need jetting help badly. It is a very poor starter and bogs a lot...I installed a Boyesen quickshot 2 and adjusted the fuel screw which helped but i'm looking for some better knowledge as far as changing the actual jets. Elev. around 2500' and usually warm temperatures. Thanks for any help.

[jjrace]

Ok you have a few things going on here.

First ditch the AP cover and go back to stock or one like the R&D or Merge that has an adjustable leak jet.

After that it is most likely hard starting for 1 or 2 reasons. 1st you need to remove the hot start plunger from the carb, grease the plunger lightly and then reinstall. AFter that adjust so there is freeplay at the lever. If that is stuck open it causes a lean condition. 2nd your pilot jet is most likely plugged up. It also could be the wrong size. Start by cleaning it out, then looking through it to make sure it is clean. Compressed air and some carb cleaner works great.

Put the carb back together and see if that helps.

If not, next step in the crf250s is to lower the float height. They are to high with that larger carb from 06-09 and when you land the excess fuel sloshes out into the cylinder. So lower the float level by about .5mm, just so that only 3/4 of the bowl fills with fuel.
Next you are going to want to modify the AP circuit in carb.

If you still have problems, be sure to try the simple things like different clips on the needle. If that does not help, then go back to the stock clip. Also they are jetted lean, so going up 1 size on the pilot usually is very helpful and keeps it from poping on decel. Leave the main stock (adjust for altitude here).

Now if nothing else so far has helped, time to modify the AP circuit. 2 ways to do it - put some money into it with getting an adjustable leak jet (mentioned earlier) or modifying the AP linkage and trying a few different size leak jets. Here is a link for you to read up on:

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

On my 450 I ended up with a #90 leak jet.

Hopefully that helps you out!

[11ChanceWeight11]

by modifying the ap linkage do you mean the o-ring mod? I thought i read on a different thread that this wasn't necessary on the 08's

[motosicko]

What jetting are you running now? Try this, 45 pilot, 172 main. Check your plug color to verify tan color.

[11ChanceWeight11]

jetting is all stock...i can't check it right now because i'm at school and bikes back home but i'll look next week when i go home and get some exact numbers...thanks for the suggestion though

[11ChanceWeight11]

alright so i switched to a 172 main and 45 pilot like you suggested and have the fuel screw about 1 3/4 turns out. Went for a short ride yesterday and it seemed to run good and started fine all day. My next question is do you think i need to change the leak jet and or ap timing for the qs2? It has a 70 leak jet in it right now and i havent touched the ap.

[motosicko]

If it's running happy now, just ride it and be happy . The AP squirt timing can be checked by removing the air box and looking inside the carb intake, and make sure the squirt isn't hitting the slide as it raises. If it hits slide, then adjust, it should just miss the slide as it raises. Leave the leak jet alone. The 250's are picky with the fuel screw setting, so get used to adjusting it for temp. and humidity changes. 1 1/2 to 2 1/2 out are within range. If it runs better more than 2 1/2 out the you need next size up pilot. Make sure you check your spark plug color.