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Idle hangs...?

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I've got an 02 CRF that has an idle problem. The idle seems to hang when it revs down. It doesn't do it all the time, but pretty close - probably 90% of the time. I tried turning the pilot jet out 1/2 a turn and that seemed to help some....but didn't try adjusting it anymore from there (I'm not sure exactly where the needle is and didn't want to turn too much). My question is - could that be caused by the pilot screw? Should I go up a needle?

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Well, my lazy butt just did a search and it sounds like that might be it. I think I've got a 42 in there. I guess I will try a 45 and see of that does the trick.

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have you had your carb apart recently?

if so check your vacuum release plate to see if it's upside down (triangle side up)

Bryce

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Well, my lazy butt just did a search and it sounds like that might be it. I think I've got a 42 in there. I guess I will try a 45 and see of that does the trick.

If it gets worse or starts spitting back through the carb and pop stalling, try a 40 pilot. The screw should be somewhere from 1 to 2 turns out.

The fuel screw doesnt work like youd think it does. You cant throw a big jet in there and then meter it with the screw.

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Thanks for the info guys - I will check it out. And yes, I will try both a 45 and 40.

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My '02 did the same thing: it was the Carb plate. It had come loose.

The flat slide has an removeable plate with a hole in it, for idle. It is held in with an o-ring and is a pressure fit. If it comes out, it will cause hanging idle for sure. Just take the slide out, and see if the plate is left behind in the carb, or is hanging loose from the slide. The use 3m weather strip adhesive to glue it back in. Use sparringly, and don't put the slide back in till it is dry (nasty fumes wreck o-rings)

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I don't think some of you really understand the vacuum release plates function it's there to keep the slide from being sucked agaist the front of the carb on closed throttle decel to avoid the slide sticking and making the throttle stick gluing it in is a very bad idea

Bryce

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I think he's talking about just gluing the seal into its proper position, not actually gluing the vac release plate to the slide. That thing has a hole in it and is supposed to leak...

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ahh that make more sense but kinda dangerous telling people to glue it in as many don't completly understand it's function but on the other hand if they don't should they really be taking it apart?

Bryce

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My '02 did the same thing: it was the Carb plate. It had come loose.

The flat slide has an removeable plate with a hole in it, for idle. It is held in with an o-ring and is a pressure fit. If it comes out, it will cause hanging idle for sure. Just take the slide out, and see if the plate is left behind in the carb, or is hanging loose from the slide. The use 3m weather strip adhesive to glue it back in. Use sparringly, and don't put the slide back in till it is dry (nasty fumes wreck o-rings)

Did yours always hang? For example, mine will idle fine, then if I blip the throttle, when it idles down, it will hang at a certain RPM. Then, if I blip again, it will usually idle down to "normal". I'd say this happens 80% of the time. Was that similar symptoms to your 02?

I pulled the slow jet and there was a 60 in there. When I put a 45 in, it would not idle without the choke on. And if I revved it, it backfired like a mofo. I originally had a FMF pipe on their with a powerbomb header - but the header pipe wore thru. So I put a stock head pipe on there with the FMF Ti4 exhaust (I think the previous owner removed the baffle as well if that makes a difference). Anyone know if that could be an issue? A collar had to be welded to the FMF exhaust to get a good seal since the opening was bigger than the stock header pipe diameter. Anyway, my plan to was to get a used 02 exhaust pipe, go to stock carb settings and go from there. If anyone else has any ideas or sugesstions, pass them on!

Krannie - were your symptoms as I described? Just curious before I go tearing into the carb.

Thanks!

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I have an 02 as well, I had the same problem, hanging idle, it drove me nuts. When I put in a recluse auto clutch, the idle was very important.

I finally took it into a dealer, he changed the pilot, The bike has never run better. He told me it was very common. Best $100.00 I have ever spent. He also took the carb apart and cleaned it up

My advise, change the pilot :banghead:

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Did yours always hang? For example, mine will idle fine, then if I blip the throttle, when it idles down, it will hang at a certain RPM. Then, if I blip again, it will usually idle down to "normal". I'd say this happens 80% of the time. Was that similar symptoms to your 02?

I pulled the slow jet and there was a 60 in there. When I put a 45 in, it would not idle without the choke on. And if I revved it, it backfired like a mofo. I originally had a FMF pipe on their with a powerbomb header - but the header pipe wore thru. So I put a stock head pipe on there with the FMF Ti4 exhaust (I think the previous owner removed the baffle as well if that makes a difference). Anyone know if that could be an issue? A collar had to be welded to the FMF exhaust to get a good seal since the opening was bigger than the stock header pipe diameter. Anyway, my plan to was to get a used 02 exhaust pipe, go to stock carb settings and go from there. If anyone else has any ideas or sugesstions, pass them on!

Krannie - were your symptoms as I described? Just curious before I go tearing into the carb.

Thanks!

You need to tear into the carb. There is definitely something in there that aint right. You shouldnt need a 60 unless you were ice racing at the south pole.

Check your vaccum release plate and make sure it's not been messed with somehow.

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I have an 02 as well, I had the same problem, hanging idle, it drove me nuts. When I put in a recluse auto clutch, the idle was very important.

I finally took it into a dealer, he changed the pilot, The bike has never run better. He told me it was very common. Best $100.00 I have ever spent. He also took the carb apart and cleaned it up

My advise, change the pilot :banghead:

There was a 60 in there - which is odd to begin with. But I went to a 45 and it would not even run without the choke out. And when it was running, if it sounded like a freakin' popcorn machine. So I don't think it's jet size.

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You need to tear into the carb. There is definitely something in there that aint right. You shouldnt need a 60 unless you were ice racing at the south pole.

Check your vaccum release plate and make sure it's not been messed with somehow.

That's my thinking too...thanks for the input.

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There was a 60 in there - which is odd to begin with. But I went to a 45 and it would not even run without the choke out. And when it was running, if it sounded like a freakin' popcorn machine. So I don't think it's jet size.

crap ya know what, I bet the vaccum release plate is upside down...(I just re-read this without children screaming in the room)...

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crap ya know what, I bet the vaccum release plate is upside down...(I just re-read this without children screaming in the room)...

Just to make sure, when you guys say vacuum release plate, you are talking about what the manual refers to as the "throttle valve plate", correct?

See pic below (dunno why it would not show up in the post):

carb.jpg

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when my throttle valve plate was installed upside down the bike would not run unless the hot start was and choke were both pulled.

Mine also had that hanging idle. I played with the idle and it ended up being just turned up too high.

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when my throttle valve plate was installed upside down the bike would not run unless the hot start was and choke were both pulled.

Don't those have more or less opposite effects? I would think using them both simultaneously would cancel each other out :banghead:

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