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Discussion Starter #1
I love my 05 KX 250 way better than the 03. But I have a poping noise under heavy throttle sounds like detenation ( Usual Kaw's come rich) The manual says that it had a 165 main then correction supplement say a 160 ( seems really lean to me but wahatever runs great but under lead still pops with VP c-12....so I moved to a 165 then 168 then a 170 (Runs Better ) . All other bike Suz , Yam, KTM have a 170'ish main. I'm in the motorcycle industry and have made phone calls to Kawi but they have not heard of anything like this. The kicker is that another bike that we sold is having the same prob. The mags have not even talked about a problem so I am thinking it is an isolated problem like someone should have typed in 170 in the supplement manual or WTF??? Just seems to be such a drastic main change from 160 to 170.
Any thoughts ???

Regards Hitec
 

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AZ's Official Mechanic
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so do a plug chop and see what it looks like with the 160 on up. when you get the plug colors you want then your good.make sure you dont have any air leaks before you burn it up and make sure you air screw is set correctly.
 

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Motorcycle Momma
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HiTech,

Welcome to the forum.....you came to the right place for answers......QKENUF4U is a man with a lot of answers!!!!

Hope to see you up here often. Enjoy and Ride Safe,

Heather
 

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Discussion Starter #4
Cool .......soooo here's what Ive' done so far. ( over the course of a couple of months )

1) broke the motor in seemed rich on the bottom but just adjusted air screw until I started to get on it.
2) Grease all suspension linkage and retighted all bolts, nuts ,screws, on engine and all frame parts.
3) Apply dieletric grease to all electrical connections ( just like on all other bikes i have had , even with the same tube. )
4) Replaced air filter with twin air.( when I noticed it the most) Maybe????
5) adjust air screw but went from a 50 pilot to a 48 then readjust air screw for proper throttle response ( went back and forth a couple of times to make sure I felt good with that.
6) Under heavy load engine was missing or popping when 3/4 to full exiting corners. Detenation ??? ( checked plug light light tan ) Using super M 32:1 50/50 race fuel. I mean like a sand berm then go up a fairly steep sand hill kind of heavy load.
7) Marked throttle grip to see where popping was ..... but without load on the motor it will not do it and the poping seems to go away when the engine gets hotter. ( lean condtion right ??)
8) Check all clamps and boot carb connections seem fine. I kept and Eye on it as it seem to come and go.
9) Installed a 165 seemed better. then 168 then a 170. only has slight popping and much better top end power. but makes top end a little sluggish.
*** I know what you are thinking hey dumb dumb you just solved you own problem right. still does it *****
10) Installed PC pipe and silencer improved power as expected but still has popping noise.
*** I have not tested the CDI , mag or the Carb yet... but I do remember some guy from the east with the exact same prob but can't remember the fix.

Thks for your help in advance !!! Regards Hitec
 

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Try lowering the clip on the needle and see if the popping???? you mean pinging right?!! stops. My 05 pinged a little bit also. I jetted the bike and changed to a leaded fuel and the bike runs awesome. You say you are mixing race fuel with pump fuel 50/50.....make sure the pump fuel isn't oxygenated or it will ping like a bugger. The 160 main should be rich enough. The carb has a different nozzle that the Yamaha and other bikes so the main jet can't be compared. :)
 

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Discussion Starter #6
Crogg... thks for your reply... pinging i would normally hear in the exhaust pipe, this is an popping noise under heavy throttle 3/4 to the stops, people have told me that they have seen a puff of smoke ( like a mise fire ) hmm like unburnt exhaust hitting a hot pipe....maybe CDI ??? but will only do it under load.... Maybe i check the mag plate to see if it's loose ?? that I hav'nt checked.

thks for your help!!!! Hitec
 

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AZ's Official Mechanic
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1. where are your air screws set now ?
2. how do the reeds look ?
3. might need to check the stator output at high rpms to make sure its high enough to keep spark in the cylinder
4. your on the main at that throttle postion so i would do a plug chop to see what the plug looks like. might be too rich/lean on top
highly doubt the CDI since usually they are like a coil , they are dead or they work
5. i would check to make sure your float height is correct also
6. if popping goes away as it gets hotter then yes its a LEAN (to little fuel) condition, i would say that your still not adjusted on the needle/main just yet since it only happens at WFO throttle postions.
good luck and keep un informed
 

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Discussion Starter #8
QKENUF4U......thks for reply. We seen to be on the same wave . I have thought about point 5, (float height) I went an purchased Kawi's float height gauge from the shop manual .... and that's as far as I have gotten ..then it snowed .( yes I thought about temp ) But I go my bike back in late Aug and here it was like 30 C or 80 F . Thks for your help EH! and I will keep posted.

Regards Hitec
 

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Team Green says to run a 165 main jet instead of the 160 at sea level. I also own an 05 KX250 and it popped when I first got it....after rejetting and performing a little port surgery the bike is scary fast and hasn't popped or pinged since!
 

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hi, im running a 50 pilot 165 main 32.1 pro 2 oil, pump fuel 97 octane (uk), results still popping like hi tecs , some folk,s say compression to high , any one got a fix for this yet ? kawasaki uk say they have not heard of any problems !" they said that about the kickstart,s !!!!!!!!!!!!!!!!!!!!!!!!
 

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I have worked on 4 05's and they all popped during the break in period with stock jetting. I live at 4000 ft above sea level and have leaned out the jetting as follows....pilot 45, clip in top position on needle, 152 main jet and all of the bikes have not popped since. In 03 Kawasaki has a too lean of a needle and the bikes would ping....this time I think they went too rich and unburnt gases may be collecting then igniting at the wrong time causing a popping noise. I have run the bike near sea level 1600 ft with the same jetting except for a 158 main and it didn't pop there either. About a month ago I went back to the stock jetting just to see what would happen and it did indeed pop occasionally. Weird?!!! I don't worry about it anymore because with proper jetting the popping hasn't returned. As far as the compression, I'm running higher compression in my 03 than the 05 without any problems! And....the compression is the same as the Yamaha YZ250. One of the 05 KX250's is 7 months old and gets raced in the pro class almost every weekend and has proven very reliable! None of the bikes have had a kick starter issue. Back to the issue at hand...Vader551, I would make some jetting changes to see if your bike will react like the other 4 I have worked on. Raise the clip to the top position and go test....then drop the main to a 160 and retest then lower the clip to the middle position and retest! Also, all the carbs that I rejetted had a high float level which will make the bike run rich. So I would set the float level first, then test and jet and test and jet! I hope you have a great outcome like I did! I run Klotz KL300 mixed a 32 to 1 with 3 gal of 91 octane pump gas to 2 gal of 100LL of av/gas! Good luck and keep us updated on your progress!
 

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Is the 05 suspension stiffer than the 03? I have an 03 and am about to send it out to Pro-Action, but am considering getting an 06 due to the motor and ergonomic improvements.
 

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kx447 said:
Is the 05 suspension stiffer than the 03? I have an 03 and am about to send it out to Pro-Action, but am considering getting an 06 due to the motor and ergonomic improvements.
Yes! The 05 suspension on the KX is both plusher and stiffer or better bottoming resistant. My son rides one in the pro class and is running stock springs and valving. It is really really good. The 06 has a few refinements that are worth getting. Go for it! Unless you want to go 4 stroke...we just picked up our KX450 and needless to say, we won't be buying any more two strokes! It's that good! :)
 

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05 KX 250. New Crank, Piston, Clutches, Chain/Sprockets, Changed mapping, minor jetting, checked power valves and reeds. Porting and Mill work on the head. Poping still disaster. However only on top end. (wide open). About to install the 168 main. Talked to team green they say try chaning the needel from a G back to a F. (makes it fatter)
 

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You need to install a NALF needle. The stock needle has the wrong taper. It is rich down low and lean up top. The NALF corrects the problem! Motors on the three I have worked on haven't pinged or popped since, even on pump gas!
 
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