area p - cyl running lean at idle

[cory jordan]

so when letting the bike idle last night i was looking to see where this noise was coming from, sounded like exhaust expansion .. so i got under the bike and noticed that one of the header pipes *left when standing infront of the bike* was glowing . now it wasnt glowing red hot like a f1 car .. but noticibly red .. i have since lowered the idle screw and babied it home.

(mods list)
2012 250r ca model.
area p full race highmount exhaust 18inch muffler
dynojet 108 or 110. i cant remember(which ever was deemed correct from area p for my elevation *central california*) mains and needle adjustment as per the instructions.
airbox/snorkel delete with sr909 k&n filter.
mixture screw adjustment as per instructed 2&3/4 from bottom.

bike runs well. .. pulls nicely all throughout the rpm range. pops a lil on decel and throws a pretty big afterfire on decel and high rpm rev.

could it just need more fuel on the adjustment/mixture screw on the carb..
any help is appreciated.'thanks=)

[Jiggles]

What's your elevation? Your DJ 108 is likely too lean, though that's not the source of this problem. You should still go to jetsrus.com and order two keihn 115s and two keihn 118s, one of those will be a more suitable main with your setup.

What is the sr909? Do you mean the K&N 0990 air filter? Can't find anything on sr909.

I have essentially the same setup as you do. Currently I'm at 2 3/4 on the mixture screws which gives an AFR around 13.5. I tried 2 turns out before and that had my AFR up in the 17s which is way too high. If you still think 2 3/4 is too lean then go to 3 out, if you have to go more than that (which you shouldn't with this setup) then order some new pilot jets from jetsrus.

Also, did you remove the CA emissions crap? If you did and its still popping thats a sure fire way to know you are too lean (get the bigger mains)

[cory jordan]

elevation is 250 ft above sea level, i am using the dj108 and for some odd reason i always have called that k&n filter sr909. i know it isnt the right name. anyhow.
yes i have also removed the *kleen air* system but havent plugged the tube on the top, *the preformed one with the metal clamp* it pops alot through decel and is quite annoying.
if i get off the throttle snap close it will burble and pop you say the 108 is likely too lean , but then say thats not the source of this problem... care to explain?

[Jiggles]

The main jet and needle won't affect your idle at all. You're saying that the cyllinder turned red while idling right? That would indicate that your idle mix is too lean. For about $10-$20 you can buy an infrared temp gun http://www.amazon.com/s/ref=nb_sb_no...perature%20gun and check the actual temps of the pipes. If one is significantly hotter than the other it could indicate that perhaps your mix screws are not synced up too well. You could also benefit from a carb sync.

As for the popping, which tube do you not have plugged? On the gas tank? On the engine?

As for you main jet, yea the DJ 108 is too lean. That is equivalent to a keihn 112. Order the keihns I mentioned earlier and try them out. I'm currently running a keihn 118

This is a dyno with dynojet 108 mains and the needle on the 4th from the top position. As you can see, for the most part it is lean.


My current setup which is working very well except when I get to about 4000ft elevation (I live in a similar elevation to you) is 118 mains, clip on the 3rd from the top position and mix screws 2 3/4 out.

Anyway, figure out why one cylinder was running hotter than the other. Try turning your mix screws all the way in and then re backing them out making sure they are at the same position. Run the bike and ride it to warm it up, bring it back home and idle it for a couple minutes checking the temperature of each pipe, note any significant differences.

Be sure you do not idle your bike for too long, its not good for it

[cory jordan]

yeah, i understand the main jet/needle relationship regarding idle, and the hose that is not plugged is on the motor. its a rather large hose.. ive been suspecting that it has been lean the whole way through. since i have opened her up.. and only at idle was there discoloration or noticable heat. after a hard 100mph pull i pull off and can look at like pipes, everything seems normal.
i beat on this bike everyday. it sees 12k+ rpm everday numerous times a day. it now has 3500 miles on it and seems to be enjoying it self. aside from the popping (which may be that residual kleen air hose)
. it has out run a couple (more than 3) different ninjas out here in the valley and almost dead even with my buddies 883 sportster. so i'd say its healthy.hell i run outta gear in 6th *hits the limiter*. so i know things are ok... . ill fiddle with the adjustment screw, and report back. thank you for your quick response.

[cory jordan]

was there any reason why you switched jets, or had you always run the 115 or 118 jets?. i have heard mixed reviews about the sizing of the dj kits. but after talking to area p for weeks ... i was pretty sure i would have a good platform to start with.. ..

honestly where my bike needs some attention would be the low end. seems like the bike could benifet from a ignition timing adjustment.. 4th and 5th are my favorite gears.. but down low it kinda falls on its face.. if you know what i mean... i know you gotta spin these motors up to get em moving.. but there is a noticible power gain at around 4k. and exhaust note change.. its almost as if im lugging the motor. regardless of the gear im in.. *aside from 1st.*

[Jiggles]

You need to get an emission block off plate for the top of the engine. Having it plugged will cause weirdness at idle, I have no idea what having it open will do.

I originally started with the DJ 108s as that is the largest one you get with the dynojet kit, I switched to keihn because I can order individual keihns from jetsrus.com. idk if there is much of a difference between brands but 115s and 118s will only run you about $12. Each jet is only $3

At 4k rpms there is a super rich spot, I've not been able to fix it with multiple different needle and main jet settings. It's probably just a way that these carbs work. After 4k the bike begins to lean out to better power.

What gearing are you running? 14/47?


btw, my 250 is faster than urs

[choneofakind]

Originally Posted by cory jordan

but there is a noticible power gain at around 4k. and exhaust note change.. its almost as if im lugging the motor.

Jiggles is on the right track with the idle mix. Even them out and see if you still have this change of sound. If the change in sound is there, bring the mix screws out to richen the mix.

[cory jordan]

here is a sample of my bike at idle .. it also does this on decel... this is what i was talking about

http://youtu.be/QN4jhrlwxC4?hd=1

[Jiggles]

Link to original page on YouTube.

[Jiggles]

Get some bigger mains

[cory jordan]

i wonder if there is more power in this bike than it is already making... .
115 or 118 ... hmm what jets.. maybe ill order them both..

[Jiggles]

Order both, put the 118s in first