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Discussion Starter #1
I installed my FCR carb. I got the main jet dialed in but still have a flat spot in the bottom. If it is sitting idling and you nail it wide open it wants to stall. No response. Just like a burp. If I ease it up a little then hit it hard it is fine. I have only ridden up and down my street since the install. I live on a dirt road. It doesn't seem to effect it when riding from what I can see but I would like to get it right. I am running a closed air box slightly modified with a larger intake snorkle. I was running a 150 main in the stock carb with a full HMF system. A 158 seems to be perfect in the FCR. It came with a 170. I went down on the pilot jet from a stock 42 to a 38. It doesn't seem to be any better. I have also had the needle in every position possible. Any ideas would be appreciated. Thanks Frank
 

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it sounds like it is getting an over load of fuel maybe trie leaning it out. trie takeing the air box lid off first and see if it gets better. Because takeing off the lid will lean it out and If it does it will tell you your going in the right direction.
 

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You did hook up the TPS didn't you? Not hooking up the TPS will cause the condition you describe.

Other than that, I can't help you much - closed airbox jetting is much different than open (I run open & the "out of the box" jetting is close for an open box)...
 

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yea, it sounds like a TPS problem to me also. The lid shouldn't make that much of a difference in the pilot.
 

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This may sound very...."elementary," but make sure you let it warm up for a long time, I know that if you try to go right away without a good warm-up period it does this and kind of boggs down on ya.

Good luck man and nice avatar :D
 

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Well, I don't know if anyone will argue or not. But, with the FCR, there is some hesitation righ out of the gate. You can't just hit the throtlle and take off. You must be on the throttle just a little bit and then hit it. My friends 41 FCR is even worse on that subject. That's why I went with the 39. Now some people will say I'm full of it, but this is my second FRC and they both work the same. I'm at sea level and I have a 42/161. If that helps at all. My 2 cents worth, of course with experience!
 

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Originally posted by TrX450rKiD@Jun 23 2004, 05:30 PM
This may sound very...."elementary," but make sure you let it warm up for a long time, I know that if you try to go right away without a good warm-up period it does this and kind of boggs down on ya.

Good luck man and nice avatar :D
that's a good point kid. i was real excited :wacko: after installing my new pipe, cleaner, and jetting. i wanted to hear that SOB roar right away. i first thought there was a prob. then i realized my impatience had made me forget to warm it up... it worked fantastic after a 10 mins. this bike is a little temperamental sometimes.

but, life is usually not that simple. <_<
 

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This is just only my 2 cents. I was told on my fcr carb which is a 40mm off the crf that the pilot was a little lean on the quad. Reason for is that the quads are heavier which takes more torque to run the machine compared to dirt bikes. So you have went to a 38 pilot and the stock is a 42. My suggestion would be to try a 45 and see were that goes. Also one thing to consider is that the accellerator pump on the carb's are adjustable. If the 45 is worse try the 42 and try adjusting the pump, try turning it in a quarter turn and if that is worse try a quarter turn out from original setting. One last thing make sure you are ridding the quad, because I have seen were there could sound like a dead spot when you a revving it up in neutral (unloaded), and the quad would actually run find when ridden (loaded). I hope this will help.
 

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Discussion Starter #10
I have gone up on the pilot all the way to a 50. I think my problem is in the needle. My friend from Greater Yamaha is going to bring hame some needles tomorrow and we are going to experiment. We have messed with the TPS, air screw and the accelerator pump. It was a flat spot when ridden also about 1/4 to 1/2 throttle. I will let you now what happens.
 

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Discussion Starter #11
My buddy from Yamaha came over with a bunch of needles and he worked on it for about 4 hours. Changing needles and needle positions. Changing the accelerator pump and the air screw. He has it close to having no bog sitting at idle when you stab it. It seemed to ride fine I really could go crazy because it is so late and my neighbors wouldn't like me too much. I will let you know what I think after I ride this weekend.
 

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Come to think of it mine kinda does the same thing if I have it in neutral, but under a load it runs good. It has not given me any type of trouble so far though, it hasn't caused me to stall out or anything ant the frags or on the mx track. Give it a chance and ride it some, you may just find that you are just being a little anal about it IMO, a quick trip up the street won't tell you much.
 

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Discussion Starter #13
You got it backwards. I could care less I told my buddy don't worry about it they all do it from what I read. He is a perfectionist. It comes from tuning the racing jet-skis and dirt bikes. He still isn't happy if it isn't perfect. He is a maniac like that. When we go riding he spends more time making other peoples bike go fast and handle better then he does riding. He did a great job on my suspension set up. We will be back on it next week.
 

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TRX450R_Racer, sounds like you have a great friend. I still think at idle and then just stab it and will hesitate. But besides that the carb helps the bike run very strong. I think way better than the stock carb. Sometimes though when I'm riding in the woods real hard and then I stop for about a minute with it idleing and then I just stab it it will die. I'm thinking because of the attitude difference! B)
 

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Good luck Frank.
 

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Well, I don't know if anyone will argue or not. But, with the FCR, there is some hesitation righ out of the gate. You can't just hit the throtlle and take off. You must be on the throttle just a little bit and then hit it. My friends 41 FCR is even worse on that subject. That's why I went with the 39. Now some people will say I'm full of it, but this is my second FRC and they both work the same. I'm at sea level and I have a 42/161. If that helps at all. My 2 cents worth, of course with experience! [/b]
So wait there is a hesitation on the FCR carb as soon as you punch it. That drive me insane!!! :( Any type of hesitation sounds like a jetting problem. Does everyone with the FCR have this problem? Gabe how about you? are you experiencing this too?
 

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Joe, mine cuts out a little in neutral, but not under a load. You just have to ride it with one, it really isn't a big deal at all.
 

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Joe, mine cuts out a little in neutral, but not under a load. You just have to ride it with one, it really isn't a big deal at all.[/b]
What do you mean by it cutting out in neutral but not under load? What if you were putting around, where you are only on the throttle a tiny bit, on and off what would it do then?
 

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Discussion Starter #19
Joe,
He means when you are sitting still idiling in nuetral and stab the gas wide open it will stumble or stall. If you are moving in gear (that is what under a load means) this won't happen. Mine is almost dialed it. Hopefully when I go riding tomorrow we can get it fine tuned.
 

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I still tend to think that is a jetting problem...try playing with your pilot/starter jet....that should dial you in.
 
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