running like crap.

[syko]

My Kx125 is hurting again.

The bottom end is still a little on the rich side so that needs sorting.
the top end sounds really crap and performs really crap.
in fact the bike runs really crap.
i know this has already been done to death on this forum but i'm stumped again.

i've changed as much as possible in the bike, new exhaust packing, fresh gear box oil, fresh fuel/oil etc just so i could make sure it was not something else.


whether i am in gear or in neutral and i open the throttle fully, the very top end kinds misfires and bogs a bit, it's a difficult noise to explain. it's a dull sound and it kinda misfires at the same time.
the bottom to three quarter range ain't too bad for revs but when i get out on the bike for 20 mins it starts to get crappy in most of the range (not as bad as top end but still rough)

i leaned the bike out throughout the range from the factory settings and the weather has warmed up here recently since i first got it but the bike was way better out of the factory even though it did foul up my plugs.

what is up with it now?

is it too lean? too rich still?
i checked the carb throughout and it's fine, the floats are cool and there is nothing else that i can see that is wrong.

my carb settings are:
pilot-37.5
clip pos-2
main jet-410
air screw-2 trns out.


any ideas?

 

[syko]

Ok,
just thought I would share this with you.
I'm still perplexed by it all but i tried this anyway.

i changed the pilot jet to a 35
the main jet to a 380
clip pos 2
air screw 1 and half turns out.
fuel mix 40:1

i fired her up and she sounds a bit better.
the top end is a lot clearer than it was. problem is i can't get out on the thing until tomorrow so i'm still left guessing.
i bought a brand new plug for it and stuck that in aswell.
she sounds reasonably crisp.
i got her warmed up and gave it some revs.
she was fired up for about 5 mins in total.
I took the plug out and it was still crisp white, now i now that usually means too lean but as it wasn't under load and i only fired her up for 5 mins the colour of the plug wouldn't signify anything would it?

any ideas on this set-up.

also, in my manual it mentions something about the fuel level in the carb and that it can be adjusted. problem is it doesn't tell you how to adjust it.
what difference to the bike does this make and how do you do it?


thanks in advance....again.

 

[marcusgunby]

If it sounds cleaner you are on the right track, ride it gently at first and listen for pinking.You have to experiment to learn-its the only way.

 

[SamMiDD]

hmmmm where did you buy the bike from? What i would do is ring Cradley Kawasaki or Corby kawasaki and ask them what they thought and if it's a problem that other people have had. Also ask them what jetting they reccomend. Is there anyone else on here with a 04 Kx125 that we know maybe it's worth asking them if they ran into any trouble regardless what country there from?

Where abouts in the west mids are you?

Is the bike smoking a lot? What you explain sounds slightly like the crank seel is going or gone but this would pull gear oil through and make the bike real smokey so if it's not i'm well wrong!

 

[Porstala F9]

What spark plug are you using? Also, what kind/brand of oil are you premixing?

I would reccomend trying an 8 and maybe going back to the 410 main. I have been using the BR8EG plug with great results since February!

And I could be mistaken, but idling/warming up the bike in neutral cant give you a good result with spark plug color.

I ran into a guy at the track with a new kx-125 and I was noticing the poor guy changing his plug every single time he stopped the bike for a break! I went over to him and asked him what was wrong, and he was obviously under the impression that the dealer gives you that this is to be expected. And I even told him how I had the same bike, yet had been on the same plug for over 4 months now. I exchanged e-mail addresses with the guy and told him to switch to a BR8EG instead of the expensive and colder heat range BR9EIX plug which also had the problem of the fragile electrode falling off and damaging the engine. I wrote down the jets to put in (37.5 and 410) and told him to go to the second clip position as well. Well, a few days ago I got an email from him telling me how much he appriciated my advice because his bike was no longer fouling spark plugs.

Story doesent have much to do with the thread, i know.. but I just thought I would share because I am so outraged by the jackasses as the dealers around here that act as if jetting is against their religion or something.

Good luck with the problem

 

[pbook]

syco ,i have been following your posts and cant believe the grief your having with this new bike.i bought a brand new honda 125 a year ago,never changed the jetting,still got the same plug in it,just stuck a dep pipe on it and a larger rear sprocket and thats it.i know they are not the fastest 125 but its crisp ,was a bit boggy when it was colder but now its getting warmer its fine.was thinking about getting a green one for next year but dont think i will bother.what do you ride ACU,AMCA

 

[Mike R.]

Seems like your having a ton of problems

I also have an 04 KX125 and I did foul one plug but, I believe it was my own fault because I let it idle to long.
I have since had it out 2 other times and rode it like I stole it.
Pulled the plug and it looked a lil rich but nothing unfixable.
I havent even done anything to mine yet its bone stockv with factory jetting. I just havent had time but it appears as going to a 37.5 over the stock 40 will cure my ills easily.
Could you have mixed your ratio wrong?
Another thing is write down what all your changing because if you dont sooner or later your going to get so confused youll have to damn near start over.
When you check the plug you need to be running it in high in the rpm range and dont come to an idle and turn it off.
Get it well warm ride it hard then when your in about third gear blasting with rpms up pull in clutch and kill it. Now you can get an accurate plug reading. You cant if you run it then let it idle then shut it off.
Good luck on your KX I am sure you will work it out.

 

[syko]

thanks for all your replies guys, as always much appreciated.

I'll try and answer some of your questions.
Sammidd; I'm from wolverhampton in the west mids, got my bike from cradley kawasaki.
the exhaust isn't smoking too much at all really.
I took it out over the weekend to a practice track near me.
at the moment i would say the bottom end is about right. sounds clear and crisp. the top end is still a little bit rough but that is not a fair analysis as i think it's the midrange where I am having the problems. i would say it's from 1/4 -3/4 range where it is at it's worst. so, i have changed the needle position to 1!!!!!
the reason i think this, is when i went out on the track first time around i fouled up my plug after two laps i bought it in and put in another plug, it wasn't brand new but it wasn't completely fouled, it was just a very dark brown (so it was on it's way out) when i fired it up again, it kicked over first time as always, no soon as i rev and get into the the second corner of the throttle range it starts to bog, then when i let the throttle go, it starts to clear up, after a bit of slight reving and idling it clears up and I am good to go.
unfortunatley even though i was on the Ragged edge of the power pand it did eventually foul up that plug too (but the plug was far from perfect anyway)


tiylu,
Is the BR8EG a safe plug to use in the KX125 04? does anyone else think this may be worth a try.
I was thinking about trying an 8 but as my manual doesn't reccomend going any hotter than a 9 i wasn't sure.

I changed my ratio from 32:1 which is 150ml of oil to 5 litres of petrol? to 40:1 which is 125ml of oil to 5 litres of petrol?
maybe it's worth trying 32:1 again??


so, at the moment i'm pretty much as lean as you can get.
main:380
pilot: 35
air screw: 3 and half turns out!!!!
clip pos: 1 (very top position)!!

 

[syko]

Also, could fuel level in the carb have anything to do with any of this?
if, so, what does it exactly mean and how do i change it??

 

[SamMiDD]

Syko have you asked Cradley kawasaki about it? they run a few riders on them like Tommy Searle so if i were you i would ask what they are running or to find out for you!

Karl Prestwood's 2c racing is not to far from you he does Marcus's bike (and i got his pipe) it might be worth sending the bike over to him to sort out as he really knows his stuff and could probably sort your bike very easily.

I'd still complain to Cradley and ask them what they suggest if you haven't done so already
I'm in Leicestershire btw.

 

[marcusgunby]

Syko you could be having problems with the fuel level in the carb-that will give a false rich condition, however im concerned that using a second hand suspect plug is giving you a bad runnign bike-you need to start with a brand new plug really.Your jetting is plenty lean now-a tad scary lean in fact, im hoping to go practicing maybe next week and maybe me you and sam can get together and have a play ride and sort your bike.A few of the 03s had bad electrics and they never ran right at the top end and yours sounds just like theres did.

 

[syko]

Yeah, that sounds good Marcus.
I'm definately up for that.
I did think that the jetting was getting a bit on the overly lean side which is why i'm thinking it has to be something else.
cradley Kawasaki have reccomended a br8eix plug to see how that goes, what do you think?
also, if it is the fuel level in the carb how do i adjust it and what do i adjust it too?

 

[syko]

Also, with the plug.
the plug was bought brand new the day before. i took it out to an open field nearby so I could really open her up and even then the plug did start to foul up just a little from about half down the ceramic part of the plug.
the end was a good tan colour then as you looked down it srted to go black then right at the bottom i think it was looking tan again.
then the following day, i took it to the track and it fouled up straight away after just 1 slow lap.

Also, feel free to email me or add me to Msn messenger if you have it.
My email is: simonlacey02@hotmail.com

 

[marcusgunby]

i dont like the eix plugs-i would almost prefer a BR8EG, i used to run a 8 heat range all the time-it shouldnt hurt it at all, maybe use the 9 on really hot days.I think Rms use a 8 and have done for years.

The fuel level is easy to adjust but not via description over the net-its the kind of thing you need to see done really-im sure others will say how to do it but i dont want to be the one who trys to explain, i would take the bike to cradley and ask them to check it and the electrics, as i rode a 03 that sounds like yours, it came out of corners ok then when you goto mid revs it just held back and kind of popped-like a rev limited coming in way too early.

 

[Porstala F9]

It could be another problem, but I would really try an 8 heat range plug like I said..

My manual reccomends from 8 -> 10 heat range plugs (from hottest to coldest) by the way, but thats for the 2003. Dont know how much has changed or not.

I have been running a BR8EG (3.50$ USD plug) so they are also cheap to experiment with jetting and such. I have had the BR8EG in there since February and I am still on the same plug today when I went riding and the plug looks as if it will hold up for a very long time at this rate. And from February to June here, we have seen weather changes from 40°F to 85°F, and I only went from a 37.5 to a 35 when it got a little warmer. I am still on the 420 main jet too, and 2nd clip position.

I would deffinetly atleast try the 8. It cant hurt it.. The only thing that most likely could hurt it however, is the current jetting you have now. Its pretty lean, and I dont know how it would effect an 8 heat range plug.

Anyway, good luck and keep us posted :)