i didnt have a problem with the idle, its pretty finicky though , just make slight adjustments then hit the throttle and let the bike idle back down till ya get where ya want it, just little turns made a good difference on mine,
YFZ FCR carb problem
Has anyone had any problems with these carbs having a high idle. I have adjusted the idle knob all the way out and the idle stays the same. When i adjust the knob in all the way the idle jumps way up. I have put a new throttle cable on and made sure it is not hanging up any where. Where the cable hooks into there is a round copper colored dial the cable goes into. When the quad is running i can turn the dial clockwise and the quad will die. I have looked into every part of the carb and i am at a loss here. I just had it bored and i was excited to see how it runs and this problem started. The quad revs great with this carb and runs good but it will not idle at a normal RPM. Any help would be greatley appreciated.
Thanks.
Thanks.
1 - 20 of 21 Posts
I can adjust the idle knob to where the quad should die and there is no change in the idle. The only way to change the idle is to turn it up. I would say it idles around 1.5 to 2 thousand rpm. i can't get the quad any lower.
make sure that you're sealed up good on your intake boots.
sounds like you could be suckin air.
another thing........... is your throttle cable long enough. never had a yamaha fcr......... but........ it may not be letting the slide return down all the way. look at it from the side with the cover off. make sure it returns all the way back.
may just need to let more adjustment out of the cable.
did'nt know if you had done that. just throwing some possibilities out.
sounds like you could be suckin air.
another thing........... is your throttle cable long enough. never had a yamaha fcr......... but........ it may not be letting the slide return down all the way. look at it from the side with the cover off. make sure it returns all the way back.
may just need to let more adjustment out of the cable.
did'nt know if you had done that. just throwing some possibilities out.
also check were the cable itself hooks into the carb if you have pressure on it it will be holding it open causing high idle issues... take the rear air cleaner stuff off or the carb off and look inside it.. you want to see a small gap under the slide if it is very large at all then that is your issue and that is most likely in the cable adjustment also if that is not the case I would go richer on the pilot jet.. it will idle high if lean.. just my thoughts
I installed a yfz throttle cable to see if the problem could be fixed, but it didn't fix the high idle. If you move the slide up and down the slide will come down but not to the position i have set it to. This happens even without the throttle cable hoocked in it. I think there might be a problem with my spring.
could be the pilot jet......what size are you using?
i am running a 42 pilot. I ran it at the dunes right after i got the carb from getting bored. The quad rips and runs great. The idle just has issues.
What size carb, what kinda boring, and who did the job?
Has the slide been out of the carb?
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.
why do you need a new throttle cable? The stock 04 cable works fine in the yfz fcr. Just installed mine and works great just have to take a little slack out of it with the adjuster on the thumb throttle. sound like the throttle cable is not releasing the slide to let the bike idle down. had to play with mine a little to. mine would run in gear with my thumb off the throttle just had to adjust the cable a little at a time.
I put a new one on because i thought that was the problem. The yfz cable is a better application fot the carb anyway. There is two nuts instead of one that help the cable stay tighter.why do you need a new throttle cable? The stock 04 cable works fine in the yfz fcr. Just installed mine and works great just have to take a little slack out of it with the adjuster on the thumb throttle. sound like the throttle cable is not releasing the slide to let the bike idle down. had to play with mine a little to. mine would run in gear with my thumb off the throttle just had to adjust the cable a little at a time.[/b]
I have a 42.5 taper bore and i sent it to KBR and i think they send it off to someone else.What size carb, what kinda boring, and who did the job?[/b]
I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.Has the slide been out of the carb?
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
G
When you take the throttle shafts apart on the fcr carbs you have to rotate the shaft to put tension on the spring so it is possible you need to put more tension on the spring, I have done quite a few Tokyo Mods springs in the FCR carbs and never had a problem maybe just not enought tension on the spring.I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.Has the slide been out of the carb?
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
[/b]
I would take the assembly apart and make sure the shaft is well lubricated and that nothing is binding up. Make sure the shaft has some grease on it. The yfz carbs have a strong spring so I doubt that's the problem. I have a yfz carb on my 05 and mine has never had a problem. The only thing I had to do was take up a little slack in the cable.
What is the tokyo mod spring? I was thinking the spring might need to be one coil tighter.When you take the throttle shafts apart on the fcr carbs you have to rotate the shaft to put tension on the spring so it is possible you need to put more tension on the spring, I have done quite a few Tokyo Mods springs in the FCR carbs and never had a problem maybe just not enought tension on the spring.I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.Has the slide been out of the carb?
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
[/b]
[/b]
G
When you take the throttle shafts apart on the fcr carbs you have to rotate the shaft to put tension on the spring so it is possible you need to put more tension on the spring, I have done quite a few Tokyo Mods springs in the FCR carbs and never had a problem maybe just not enought tension on the spring.I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.<div class='quotemain'>Has the slide been out of the carb?QUOTE(jshtex @ Sep 22 2008, 03:36 PM) index.php?act=findpost&pid=560964
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
[/b]
[/b][/quote]
What is the tokyo mod spring? I was thinking the spring might need to be one coil tighter.
[/b][/quote]
It is a lighter pull spring to ease up on thumb fatigue.
What is the tokyo mod spring? I was thinking the spring might need to be one coil tighter.When you take the throttle shafts apart on the fcr carbs you have to rotate the shaft to put tension on the spring so it is possible you need to put more tension on the spring, I have done quite a few Tokyo Mods springs in the FCR carbs and never had a problem maybe just not enought tension on the spring.<div class='quotemain'>QUOTE(sandplayer @ Sep 22 2008, 05:32 PM) index.php?act=findpost&pid=561085I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.Has the slide been out of the carb?
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
[/b]
[/b]
[/b][/quote]
It is a lighter pull spring to ease up on thumb fatigue.
[/b][/quote]
Does it replace the stock spring? Where can i find one and read some information about it?
When you take the throttle shafts apart on the fcr carbs you have to rotate the shaft to put tension on the spring so it is possible you need to put more tension on the spring, I have done quite a few Tokyo Mods springs in the FCR carbs and never had a problem maybe just not enought tension on the spring.I did take the slide out of the carb but i made sure the M was facing out and not a W. Is there a chance the spring could be worn out? That is what it feels like. I can rotate and push the slide down about 1mm. If i hold this and adjust the idle the quad runs perfect. If i let go of it the quad idles up.<div class='quotemain'>QUOTE(TRX450RACER174 @ Sep 22 2008, 06:36 PM) index.php?act=findpost&pid=561089<div class='quotemain'>Has the slide been out of the carb?QUOTE(jshtex @ Sep 22 2008, 03:36 PM) index.php?act=findpost&pid=560964
I am asking because if it has and the cover was put on upside down you will have those symptoms.
The fast way to check is to look down the throat of the carb and look for an M stamped on the cover of the slide. If you see a W it is upside down. At least thats the way I remember it. I will check later when I get home.[/b]
[/b]
[/b][/quote]
What is the tokyo mod spring? I was thinking the spring might need to be one coil tighter.
[/b][/quote]
It is a lighter pull spring to ease up on thumb fatigue.
[/b][/quote]
Does it replace the stock spring? Where can i find one and read some information about it?
[/b][/quote]
Yes, it replaces the stock spring. Here's a link to it.
http://www.tokyomods.com/yamaha/04-07%20YFZ450.html
1 - 20 of 21 Posts
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