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Discussion Starter · #1 ·
Took the bike out for the first time this year. It has been sitting since November. I started and let it run for a while probably once a month though. Changed the brake lines to s/s, sprockets and chain, cleaned K&N air filter, changed oil. Anyway, took it for a ride and everything seems great... Normal acceleration is fine, but then, when I seriously open it up, it bogs, sputters, and coughs. It doesn't clear up if I keep it pegged either. I think it is probably the carbs. Floats or needles sticking maybe? Anyone have any suggestions on what I should look for or address? I don't want to have to tear down that far and put it back together and find out I didn't fix it. Thanks in advance.

1 Boot -- No Kick

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I posted the problem on another forum after getting my bike back from a shop. Mine was similar to yours but only occured when i rolled off the gas and back on and it was stronger in higher gears. From what im told its the jets. Have the jets checked. They also said it could be the float bowls. There could be new info on the thread since i havent checked in over the weekend and i havent been able to check my jets because im waiting for new sleeve to fix my exhaust leak. Let me link you to the post.

Some info here
http://www.sportbikeworld.com/forums/showthread.php?s=&threadid=20091&perpage=10&pagenumber=1

More info on this thread-started out as a cam chain thread but i added a question to it because these guys are pretty helpful

http://www.sportbikeworld.com/forums/showthread.php?s=&threadid=18341&perpage=10&pagenumber=1

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Discussion Starter · #3 ·
Thanks Nemesis, that helps. I was already going to drain the carbs tonight and see
if that helped. If not then I am goin to have to start tearing stuff apart and
check the Jets. I really don't want to have to dive that deep though. I live in
Anaheim hills. I have a 2 brothers full system. I don't know if my exhaust can will
fit on your pipe, but if you want to eliminate that and don't mind the ride out,
I will oblige. Let me know.

1Boot

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Thanks.. I'll keep that in mind but i may not need it. I decided that i want to regain that hp loss anyway from the leak and get the new sleeve and repack the exhaust. After that im gonna have the jets checked. Then we'll know what MY end of the problem is/was. Lets hope yours isnt as much trouble.

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ehasbeen
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One thing to check is that since your bike uses ram air the carbs must also be hooked up to the air box. What will happen if this line is kinked or not connected is that a higher pressure will be inside the throat of the carb than in the float bowl at high speed and you will loose the venturi effect. So if the carbs are also hooked up to the ram air the bowls will also have the higher pressure and the venturi effect will again work.
Since you cleaned your filter I bet this is it.
Todd

 

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Discussion Starter · #6 ·
I appreciate the suggestion Indiana, but could you please translate that to english for me? /images/icons/smile.gif

I drained the float bowls then took her for a ride. Still happening.

Nemesis, what shop do you use? I haven't been able to find a good one.

Guess I am going to have to take apart the carbs and inspect for leaks/dust/etc. I really don't want to though because I have never done it before and will be VERY frustrated if the bike is out for several months. Anyone else have any suggestions?

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Im with Fred.. english please? lol

Fred-i dont have a shop that i go to regularly but i took my bike in to Bamm Motorsports in bellflower and im hoping that if they take care of me right everytime i'll continue going there. So far no complaints. But im no mechanic so how would i know what to complain about. I probably wouldnt go to a shop so often except that im too lazy to learn this stuff myself. But i plan on having all the major stuff finished so i wont have to go to a shop regularly. I believe and also told so that its my jets which are causing my hesitation. When i get my sleeve in i'll be able to find out for sure.

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Discussion Starter · #8 ·
Let me add some more information.

First the bike is a CA model.
Second, here is some more specific yet no less confusing info:

It seemed like the lower the gear, the higher I could take it in the RPM's. 1st to 10-11K, 2nd to 9-10K, 3rd to 8-9 K
but it wasn't extremely consistent. Sometimes in 3rd around 4-5K it would start bogging even if I gave it a little gas.

Also, I don't know if "bogging" is a good term. It sputters a lot, the bike decelerates as if I had just closed the throttle and no matter how long I keep the throttle on, it doesn't all of a sudden stop sputtering and take off...

I am thinking that what IndianaRR meant was that at speed, because of ram air, a pinched/broken/bad vaccuum tube is causing unequal pressure in the carbs. So I should check all the vaccuum hoses for problems?

I looked at my service manual last night and it looks like it is a huge PITA to take off and clean all the carbs. (this is assuming that some dirt got in the jets or that something is sticking...) I don't think that is something my skills are ready to deal with, especially with the weather improving daily. I will probably take it to a shop if it comes to that. I would be OK with checking all the hoses and replacing as necessary though. That'll be a PITA too, but not as much of one as the carbs. Another problem with me doing work on the carbs myself is that I have no bench and a SMALL garage to work with. That already has 3 other bikes in it. One of which is in the process of being painted. Argh! (side note: I really need to get my own place with a decent garage. No more of this Apartment/roommate crap!)

Does that prompt any more suggestions?
Thanks in Advance
-- 1Boot

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sounds like the ol kinked fuel line to me,....mostly by using that last bit o' information you gave about being able to go higher rpm in the lower gears before the problem happens.

Doesn't sound like you're getting fuel flow. I'm guessing you had the tank off for the air filter work, right?

Take the tank off again, have an assistant hold it and VERY CAREFULLY check out the hoses going from the tank to the carb and the hoses for 'venting'.

The Ram Air thing by IRR is a good thing to check too. I didn't read the entire thread real close, but he's asking you to ensure that any rubbery or plastic ram air pieces are PROPERLY connected to/through the frame and from the air box to/through the frame. Double check these.




BA
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ehasbeen
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I mentioned Venturi effect. That is basically the principle that allows carburators to work. Here is a brief explanation on how the carb works.
A carburator always has a larger intake than exit. (ie the air box diameter is larger than the engine side) What this does is allow a larger volume of air into the carb and as it narrows down the velocity increases. This velocity increase in the air through the carb in turn lowers the pressure. At the smallest diameter of the carb is where the velocity is the greatest and where the pressure is the lowest. This low pressure allows the fuel to basically be pushed out of the carburator bowls through the jets by the higer pressure in the carburators.
If you look real close you will notice that your carbs have a couple of small holes at the bottom of the butterfly. This is where the gas flows during idle. Because there isn't much air flow the pressure in the throat isn't low enough to pull fuel from the main. But where the butterfly is only allowing a small area for air flow is where the pressure is low and creating the venturi effect.
So in a nut shell fuel will only flow from a higher pressure zone to a lower pressure zone. If you have ram air on your bike and forget to hook up the carb vent tube to the ram air system the carb pressure will not be high enough for fuel to flow at high speeds.
Sorry but that's the best I can do right now. I just finished a Physics test about Einsteins Postulates of Relativity. That is some far out $hit. One of the questions on the test was like this. If a sub atomic particle is traveling through space and has 7 times the energy as at rest. Determine the velocity and deterermine the speed of a projectile fired in opposite direction at the rate of .64c by an observer at earth. I'm probably going to have nightmares tonight. Where's my beer.... :)


 

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If Indian is wrong then its most likely the same problem as me which i havent concluded yet because i dont have the parts for my slip on yet. Jets Jets jets. Your description is very similar to mine. It doesnt really affect my riding except when im in 6th and of course its not fun to have it sputter.

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Discussion Starter · #12 ·
Just to update, the problem is fixed. I tore the carbs out and cleaned everything. Darn Clogged main-jet! Thanks for the help everyone.

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My F3 started to bog down under WFO in 4th 5th and 6th gears recently. I didn't pay it much mind cause it's not often that I go WFO on the roads :laugh:

But last weekend, my battery died. Replaced the battery and the bike just runs better :shocked:, I get no more bog down or engine misses in the higher gears. Plus the bike seems torqueier(sp?) in the lower rpms, not much but noticible :smile:

How old is your battery? :grin:
 
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