CBR 600F3 1995 - 1998 CBR 600F3 Forum

Engine Idle will not stay low

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Old 08-09-2010, 01:00 AM
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Default Engine Idle will not stay low

I already searched for this else-ware and had no luck for my exact problem.
When I start up my bike I never have a problem and it usually starts up at 1600rpm
and then after riding a for around 10 mins it may warm up to 2000. Only recently did my bike start to raise its resting idle speed at around 2700 to 3000rpm after about 20 mins of real riding. I adjust the idle and it goes down to what i set it at until i start riding again and crank the engine out.

What should I do? Is it bad for me to be always turning the idle **** to compensate for my high rpm?
 
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Old 08-09-2010, 08:49 AM
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i feel like that if you keep turning the idle **** to lower the idle rpm's then your either going to tighten the screw to where it wont tighten anymore or you are going to unscrew it (i dont remember which way does what)..either way it shouldnt be all the way in or out.. i would check the screw that goes into the carbs and see if you find anything there.

if not clean the carbs then (seafoam is the easiest option IMO)..maybe your jets are getting stuck open? you could also try and sycn your carbs, ive heard it helps with this but i have no idea how to do this.
 
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Old 08-09-2010, 01:59 PM
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if not clean the carbs then (seafoam is the easiest option IMO)..maybe your jets are getting stuck open? you could also try and sycn your carbs, ive heard it helps with this but i have no idea how to do this.[/QUOTE]

Ha that all sound like alot of fun the carbs should be fine Ive been putting some mild cleaner through it ever other tank for a while now. Its a shame Im only new to engines and taking bikes a part because a carb sync sounds out of my realm.
 
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Old 08-09-2010, 04:42 PM
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To be honest I think you can do it. I wanted the guy who did mine and wished I didn't pay him the money to do it. it is easy once you get everything off. tank, airbox, etc...
 
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Old 08-09-2010, 07:16 PM
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i think all carbed bikes act this way to some degree. it sounds like your original idle set was while the engine was still cold, and as it warms up, its naturally going to raise the idle.

i know with my bike, if i dont get it warmed properly, it 1.) will have a super low idle speed without the choke, and 2.) will more than likely stall when trying to take off. so what i do now, is start the bike with full choke, once rpms jump, let some choke out till the rpms drop back to about 2k, once it jumps again, lower to 2k, another jump, lower to 2 k...as man times as needed untill it goes a solid 1-2 minutes without raising idle....when i go with this approach, i almost NEVER have a problem with low rpm's without choke, or stalling problems.

so with that said, set your idle when the bike is at PROPER running temps...when you go to ride the bike when its cold...DO NOT RE-ADJUST YOUR IDLE SCREW. if the bike wont ride, ITS NOT WARMED UP...just keep choking it until it is...


hope this helps!
 
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Old 08-09-2010, 07:27 PM
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Originally Posted by Will.Bass
i think all carbed bikes act this way to some degree. it sounds like your original idle set was while the engine was still cold, and as it warms up, its naturally going to raise the idle.

i know with my bike, if i dont get it warmed properly, it 1.) will have a super low idle speed without the choke, and 2.) will more than likely stall when trying to take off. so what i do now, is start the bike with full choke, once rpms jump, let some choke out till the rpms drop back to about 2k, once it jumps again, lower to 2k, another jump, lower to 2 k...as man times as needed untill it goes a solid 1-2 minutes without raising idle....when i go with this approach, i almost NEVER have a problem with low rpm's without choke, or stalling problems.

so with that said, set your idle when the bike is at PROPER running temps...when you go to ride the bike when its cold...DO NOT RE-ADJUST YOUR IDLE SCREW. if the bike wont ride, ITS NOT WARMED UP...just keep choking it until it is...


hope this helps!
Well i usually dont mess with the idle speed when its warming up, thats the only time when its at where it should be around 1300. It is usually fine for like 20 mins of riding but if i put it through some stress every time i stop i notice that the rpms are up to 2200 2500 2700 or sometimes 3000+
 
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Old 08-09-2010, 08:20 PM
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take your gas tank off and move your choke all the way in and out several times, and make sure you see it moving the slide on the far right carbs (near #3 and #4). also turn your idle set screw and see if you can see it moving on the carbs as well. this is the first things obvious i can think of.

now. when you get bored one weekend and have a 12 pack of beer, take your carbs off the bike. search on this forum for a "how to:" on cleaning carbs. CLEAN THAT IDLE JET!!!

also, it wouldnt hurt to replace your spark plugs with some new ones.

check your ram air duct under the headlight. make sure theres no rats nest. download yourself an online cbr600 f3 manual (again, search on this forum for that), and look up the page on vacuum lines. make sure yours are routed the way the diagram says. also make sure that you have the clamps on the nipples that the vacuum lines attatch to.

how old is your battery?
 
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Old 08-10-2010, 02:10 AM
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Originally Posted by intiractive
take your gas tank off and move your choke all the way in and out several times, and make sure you see it moving the slide on the far right carbs (near #3 and #4). also turn your idle set screw and see if you can see it moving on the carbs as well. this is the first things obvious i can think of.

now. when you get bored one weekend and have a 12 pack of beer, take your carbs off the bike. search on this forum for a "how to:" on cleaning carbs. CLEAN THAT IDLE JET!!!

also, it wouldnt hurt to replace your spark plugs with some new ones.

check your ram air duct under the headlight. make sure theres no rats nest. download yourself an online cbr600 f3 manual (again, search on this forum for that), and look up the page on vacuum lines. make sure yours are routed the way the diagram says. also make sure that you have the clamps on the nipples that the vacuum lines attatch to.

how old is your battery?
Thanks for the reply, I now know what I must do... Finally take my bike a part, get to know her and bring her back to life.

The battery has got to be kinda old but Ive never had a problem with it. Worth checking out.

I threw some carb cleaner in the tank today and ran it in my garage, it overheated after like 10 mins and died. Ill let the stuff work in till the morning.
 
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Old 08-10-2010, 07:14 AM
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Originally Posted by Hootie233
I threw some carb cleaner in the tank today and ran it in my garage, it overheated after like 10 mins and died. Ill let the stuff work in till the morning.
its going to overheat regardless of the cleaner or not if the bike is just sittin there. no forced induction so gotta be moving to get some air. i cant explain the dying though.
 
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Old 08-10-2010, 11:35 AM
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Originally Posted by dcaldwell
its going to overheat regardless of the cleaner or not if the bike is just sittin there. no forced induction so gotta be moving to get some air. i cant explain the dying though.

.....not exactly. there's a rad fan. sounds like he has a bad fan motor switch (or a thermoswitch as people on here call it) as well ....


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