Bike idles high when warm


11 replies to this topic
  • lmaballa

Posted October 10, 2008 - 01:52 PM

#1

I know a couple of people here have given me some ideas but I tried and it still does it.

Its driving me crazy so im making a thread!

My bike idles fine when I just start it but when it gets a warm it starts idling high. I dont know what the problem is? I already replaced both exhaust gaskets: the one that goes between the two pipes and the one that goes between the header and head. I looked for other air leaks around the carb boots and made sure they were tight and I found nothing. However, my bike is somewhat losing coolant, but not much. I toped it off yesterday as I went riding for like 2hours and then when I got home the coolant was a little less than half way between the top of the radiator and the metal finned wall that you see when you look in the radiator. But the other day it was coming from the overflow hose and then after like 3 rides it was just a hair under the metal wall. I changed the oil and I didnt see any fluid in the oil. Now my question is if coolant is dripping into the head and burning it, I wouldnt see it in the oil right? Would burning coolant make the bike idle high? I just replaced the gasket between the header and the head, and the inside of the head was still black, but the header is kind of white inside, the exhaust can is black.

Do you guys have anyother tips of what to check? Is it the head gasket?

Its driving me crazy!!!:D

  • Pr1malR8gw

Posted October 10, 2008 - 02:22 PM

#2

If you have a white smoke coming out of the tail pipe you're burning coolant and probably due to a blown head gasket... if you're loosing it in the oil you will have a chokolate milk type look to your oil..
You could also be loosing it through the wheep hole.

More then likly the bike is just running hot and is being overflowed out the blow off of the radiator cap. This is normal if you don't keep a good airflow over the rad and more so in the 04-05s with smaller rads and a poor waterpump design.

As far as idleing goes. you have a knob that controls idle speed. turn it down. to the correct idle speed when its hot.

You don't want a correct idle speed when cold. that is what the choke is for.

My bike spits and sputters for a little bit when its cold. I choke it and ride for a few seconds till its warm then she idles great.

The reason why the header is white right out of the head is due to the extream heat burning the residue off. the rest of the gases get pushed out.
This is normal don't worry about that.

I think I covered everything you asked.

Rule of thumb I could be wrong and anyone else can feel free to correct me but I think i'm about right.

  • the white stallion

Posted October 10, 2008 - 02:31 PM

#3

I did a search for Hanging idle in the general,kxf 250 & 450 forums But not the CRF forums which also probably have some info.Read some of them.I clicked a link to one http://www.thumperta...698#post3580698

Does your bike still pop?

  • YZFdude2020

Posted October 10, 2008 - 02:31 PM

#4

you might be a little lean aswell, in which case it will idle higher and run hotter (where you might be losing coolant due to overflow) richen it up a clip or so and screw wit your air screw, then turn your idle down. Carbs are not perfect you have to fool with them constantly, which is why they are adjustable yo :D doesnt sound like its anything really big tho so your bike is probably fine. common stuff

  • Pr1malR8gw

Posted October 10, 2008 - 02:57 PM

#5

Hey white, he didn't say anything about a hanging idle. How ever when I wrote my reply I did think about it. I never mentioned it cause he wasn't realy giving enough info.

Yz, You could be right about being lean. how ever I would still turn down the idle first then cheack jetting.

  • YZFdude2020

Posted October 10, 2008 - 03:10 PM

#6

yeah good cold idle isnt "good" it should idle kinda crappy without the choke if at all thats why the choke is there, when its hot it should be nice and smooth burburburburburburburbuurbrrbbrbuurbubur, get it dude with wierd idle problem?

  • lmaballa

Posted October 10, 2008 - 03:19 PM

#7

Yea that makes perfect sense now, never really looked at it that way. Im still trying to learn alot about my bike, I only had it for a month. Anyway, I am going to turn the idle down and see if that helps.

I just changed the gasket between the two pipes and it doesnt pop much at all and today I replaced the other gasket between the header and the motor, which was damage, so hopefully its not popping anymore. ill just have to ride it today or tomororw.

Thanks for all the help guys

  • YZFdude2020

Posted October 10, 2008 - 03:21 PM

#8

no prob, hit back if you have any more issues, till then learn how your bike works and stuff, AND if you mess with your carb, MAKE SURE TO WRITE DOWN WHAT EVERYTHING IS SET AT NOW(clip position, air screw turns, jet sizes ect) you gotta keep track of that stuff so you can figure out which way to go and you can always go back, ok?

  • the white stallion

Posted October 10, 2008 - 04:17 PM

#9

Hey white, he didn't say anything about a hanging idle. How ever when I wrote my reply I did think about it. I never mentioned it cause he wasn't realy giving enough info.

Yz, You could be right about being lean. how ever I would still turn down the idle first then cheack jetting.


Hey pr1mal :D !:worthy: :ride: :ride:

They op has about 4 different post on the same thing So I mighta been thinking about another explanation.I don't know about you but my bikes idle fine when cold once off the choke.In the end it all amounts to the same thing his idle is like you say maybe to high or he's lean on the pilot and thanks for riding my coat tails YZ250dude.

  • YZFdude2020

Posted October 10, 2008 - 04:21 PM

#10

Hey pr1mal :worthy: !:ride: :ride: :ride:

haha :D

  • monster-04

Posted October 10, 2008 - 07:54 PM

#11

my buddy and i both have 2004 kxf250's and mine was popping like a mofo on deacceleration = way to lean primary circuit -> richen it up now idles perfect and no backfire or poping!!

Buddys has a coolent loss issue = oil fine, plugs tanned, runs good = head gasket all thats left to check

He has installed a high pressure rad cap, yet its still pushing out the overflow when riding.. only cuase is running to hot, yet he has a full Pro-circuit water pump and impeller kit installed..

tomorrow im putting a new head gasket in his bike well see if that fixes his problem before he messes it up bad haha!!

So check your mixture screw on the bottom of your carb, and maybe replace your head gaskget again or re-torque the head bolts.

  • lmaballa

Posted October 11, 2008 - 09:21 AM

#12

Hey Monster let me know if that headgasket fixs your coolant loss problem. Thanks for the reply





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