04-02-2008, 08:11 PM
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#2 |
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Join Date: Mar 2008
Location: Jackson/Lansing, Michigan
Posts: 74
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No, it's because your carbs aren't tuned correctly.
If your bike will run fine with a little bit of choke, that means it's running lean. Before you sell your bike, you should take the carb completely apart and clean it. Set it back up exactly as it was when you first started. If you need to, remove the block and turn the idle air screw all the way in. Then turn it out 2 full turns. That's a good starting point for your idle. |
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04-02-2008, 08:28 PM
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#3 |
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Join Date: Jan 2008
Posts: 147
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it was on full choke....does that apply also?...more choke the better it ran...
Took carb apart today...was clean...... Idle air screw? aren't those 2 different screws? one idle and one air mix Have ran it at 2 turns ...does same.... Wouldn't choke make it lean? not rich This is totally backwards thinking for me.. |
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04-02-2008, 08:29 PM
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#4 |
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Join Date: Mar 2008
Location: Jackson/Lansing, Michigan
Posts: 74
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One thing that you need to remember about carbs is that they are very tricky and very finicky things.
I chased some carb issues for WEEKS on my race 250 before I finally got it running the way that I wanted it to. Also remember that there are three parts of the carb's jetting...the pilot jet, the main jet, and the needle. All of these things can be replaced, but not all of them need to be replaced sometimes. Carb tuning is like 20% know-how and 80% magic. You just have to mess with it until it's right. I know that it can be a hassle to rip the carb off over and over...but once you get it dialed in you SHOULD be more or less set for the life of the thing. Don't forget that in addition to those needles and jets the idle air screw may need to be adjusted. On MOST bikes sold in the US, the idle air screw is "tamper proof." Meaning that it is sealed up by a small plastic cover so that you can't get to it very easily...the key to this though, is that it's only there to discourage you, not to make it impossible. Find the spot for it and drill a very small hole...go slowly because it's very thin plastic. After you get that hole, put a screw through the hole and then with pliers pull on the screw. That small plastic cap should pull out giving you access to that idle mixture screw. From what you've said you're experiencing, I would say that your carb is seriously out of tune. I may be wrong, but didn't you say the bike was bogging really badly but also leaving soot on the spark plugs?? That would suggest that the bike is running very rich. But now you say that the bike runs fine with a little choke...which would suggest the bike is running lean. So that sounds to me like the carb itself is way out of tune. I would start by readjusting the idle mixture screw like I suggested up above. That will give you a good start. If you get that adjusted and are still running rich, it's highly possible that the jet in the carb is too large. The one thing that I would suggest before doing any of this would be this: check to make ABSOLUTELY sure that the choke on the bike is completely disengaged when you have it "closed" on the control levers. Also make sure that your throttle plates are closed completely when the throttle is in the idle position. These two things being out of whack could really throw the fuel mixture off balance. Like I said, carbs are tricky, but you CAN make them work. Don't just get rid of the bike because of an issue like this...because if you do, you won't have the experience to deal with it when it comes up on your next bike. |
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04-02-2008, 08:29 PM
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#5 |
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Join Date: Mar 2008
Location: Jackson/Lansing, Michigan
Posts: 74
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No, applying choke allows more gas to enter the combustion chamber. Rich. It does this because cold fuel vaporizes quite a bit slower than warm fuel. The choke is actually "choking" the engine...just like when you and I choke, we're not getting air...as such, an engine is not getting air when it's choked.
To be honest, if you are thinking backwards on this whole issue, then that is going to be the main problem. I would suggest going and doing a bit of research as to how a carb actually works before attempting to mess with it anymore, because not understanding what even the choke does tells me that maybe you aren't very sure about what most parts of the carb do. I'm sorry if that sounds a bit harsh, and it is not meant to insult you, but messing with things that you have a backwards (or none at all) understanding of can just lead to more and more problems. You are correct that there are two screws that have to do with the idle. One is the idle knob itself. When turning that one with the bike running you should immediately notice the RPMs climb or lower...that should be an easy to find knob or screw hooked to the carb. What it actually does is slightly open or close the throttle plate just a little depending on which way you turn it...IE, it lets in more or less fuel mixture. The idle air screw is one that is NOT easily accessible from the outside of the carb. It will most likely be covered by a plastic plug. It's set at the factory. It actually affects the air and fuel mixture of the carb. So, in short...idle air screw actually adjusts mixture. Idle knob adjusts how much of that mixture is being allowed into the combustion chamber. |
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04-02-2008, 08:49 PM
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#6 | |
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Join Date: Apr 2007
Location: Show Low Arizona
Posts: 2,889
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Quote:
Whoops already got answered, Sorry I'm at work so It took me a while to hit the submit button :oops:
__________________
<br />2001 Suzuki DR200SE<br />1997 Suzuki RM250 YIKES<br />1995 Yamaha Breeze 125 daughters<br />1991 Honda XR80r Restored<br />maybe a 2003 Yamaha TTR90 |
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04-02-2008, 08:51 PM
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#7 |
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Join Date: Jan 2008
Posts: 147
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This is my air mix screw... the one with the blue mark... the one with the spring is idle...
I have adjusted the air screw anywheres fron 1.5 turns to 3... same bogging...no difference whatsoever..  This is my carb  I guess I need a pro to help.... Just dont wanna pay big $$$ to get it done |
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04-02-2008, 09:11 PM
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#11 | |
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Join Date: Jul 2007
Location: Independence,Missouri
Posts: 1,049
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Quote:
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04-02-2008, 09:18 PM
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#12 |
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Join Date: Jul 2007
Location: Independence,Missouri
Posts: 1,049
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Here is a post I stold from another site it was helpful to me.
Alot of people have a hard time starting and running the Chinese atv's when new and also when cold. Most of these come with a gelpac in the carb floatbowl for shipping so it does not ruin the float. It is supposed to dissolve when fuel mixes with it. Many make the mistake of driving the atv once started. This is a mistake. You must let it idle for at least 30min for the gel to dissolve. If you do not do this you will risk the chance of clogging the jets and the initial adjustments will not work and it will not run right untill all the gel is gone. Most of the time these will start with the movement of the choke then you can lightly feather the throttle to keep it running. If you can reach the idle screw you can turn it up till you dont have to feather the throttle. After about 30 min you can make the final adjustments. CHANGE THE OIL BEFORE YOU RIDE!!! These come with a cheap shipping oil and must be changed or engine damage will occure. It is best to use an oil that is classified JASO MA certified made for 4 stroke or motorcycle engines which are made for wet clutch applications. These have no friction modifiers that are bad for clutches. You can even use diesel oil like Rotella-T 15w40. These oils can be found at your local WalMart or autoparts store. Synthetics are fine as long as it has the same classifications listed above. The idle screw is the screw on the carb with a SPRING around it. The air/fuel screw is the flathead screw usually before the idle screw closest to the air filter. Some newer carbs have the a/f screw on the bottom of the float bowl. Here are some basic adjustments to get it started and to tune it once broke in. The mixture screw had been set-up at the factory before shipment and should not have to be reset. Only a small adjustment may be needed due to climate and elevation. If necessary, refer to the adjustment as below: 1. Make sure the air cleaner is clean. 2. make sure the choke lever is OFF while running. 3. Warm the engine up for 3-5 minutes. 4. Turn the mixture screw clockwise until fully closed, then turn the mixture screw 2 full turns out. 5. Adjust the idling screw until the engine idles EASILY. 6. Turn the mixture screw slightly clockwise and counterclockwise until the highest engine REVs is obtained. 7. Adjust the idling screw again until the engine idles EASILY. 8. Repeat step 6 & 7 till you get the best performance... *ENGINE IDLES EASILY means: The engine idling screw must be set correctly to get a slowest engine idle(1500 rpm - 1600 rpm), but does not cut out if you press the accelerator quickly. Cold weather starting will need an additional adjustment to help aid the starting process. Most of the manual choke carbs have an adjustable needle inside the carb. Lowering the clip (raising the needle) you will be able to open the throttle and get more fuel into the intake quicker. This helps in the cold weather because the colder the weather the leaner the mixture is. You want richer in the colder weather. 1- Unscrew and pull the top of the carb off with the cable and there will be a slide with the needle in the center. (Notice the way the carb slide came out) In step #6 it must go back in the same way it came out. 2- Disconnect the cable through a small slot in the side of the slide. 3- Now you can take the needle out from the slide. 4- The needle will have a very small e clip in a slot on the needle. The needle will have 5 slots. Lowering the clip is richer the and raising the clip will lean it out. 5- Put the clip on the lowest setting for cold weather. DO NOT DROP THE CLIP! They are very small and hard to find. 6- Reverse the process with installing the needle back into the slide, installing the cable, slide the slide back into the carb and screw the cap tight. Remember in step #1 how the slide came out. It MUST go back in the same way. 7- Now make any adjustments as stated above in the carb tuning. WARNING!!!WARNING!!WARNING!!! Remember in step #1 and step #6 I said the slide must go back in the same way it came out? The slide will go in 2 ways. ONLY 1 way is the right way. If the slide is not put in the same way, upon start the quad will take off at full throttle. Make sure when you go to start the quad you have a hand on the kill tether or switch this way if it does take off you can dissable it. If this happens the slide was put back in 180 degrees out. This is very important for the safety of you and anyone standing in front of or around the quad. These steps will work on 99% of these atv's. They are very hard to get running and people get upset when they turn the key and it does not run. Dont forget these are not set up at a dealer like the name brands so the most basic adjustments are done from the factory. These are built in china and the temps are hot so thats how the adjustments are done. As we all know in America the temps vary and these are not set at all for cold temps. In some cases you will have tuned the quad and it runs very well but one day it will not idle or has poor performance. Most times it is because the carb has sucked in some debris from the tank. You will have to dissasemble the carb and clean out the pilot and main jet. Make sure you have a good inline fuel filter. This will help prevent this failure. Hopefully this helps everyone with these concerns. These really do run good once tuned properly and with proper maintenance they will last a long time. And if you have any questions PM me and I will try to help as best as I can. Also once the temps start to get hot you may need to raise the clip for the warmer temps. Good Luck! |
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04-02-2008, 09:37 PM
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#13 |
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Join Date: Jun 2006
Location: directly under the earths sun............NOW
Posts: 2,302
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OK once again.
Basic carb tuning here please just look at the link above it will help you alot. And like everyone has said : If you apply the choke and it runs much better then the carb is set lean or has an air leak but with the choke blocking some of the air it richens it up.(less air=more fuel=better air/fuel ratio) Look for something blocking the main jet and and lower the clip to the bottom or second from the bottom on the needle. The fuel mixture screw can be anywhere from 1-3/4 turns out to 2-1/2 (you have to fine tune it-LOOK AT THE LINK ABOVE) Also look for another source of an air leak from carb and intake manifold. remember once you get it running right you will have a blast on it. :wink: |
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04-02-2008, 09:59 PM
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#14 |
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Guest
Posts: n/a
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me and my buddy got is harley running yesterday...its a beast. i eventually talked him into using some starting fluid. started and it is so freaking loud (its a big 93 full dresser) that you can feel it rumbling the concrete on the floor. and talk about vibrate. he is the sort of person that doesnt like to draw too much attention to themselves and I honestly think that may be why the bike is rarely ridden. it sounds like a dragster!!!!
lol...was fun tinkering with it though. sry bout the thredjack..just had to spout. |
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04-02-2008, 10:22 PM
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#15 |
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Join Date: Jan 2008
Posts: 147
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I have read that link teamcheap... I guess I am no mechanic...
I will read over it agin and again.... This is why I work with computers.... Setup an OC3 or DS3 line in a center and install voip and network 1000 computers...No prob been there done that... Adjust some tiny screws and I become a moron.... Really guys I am not as stupid as I sound  Thank you so much for your help and patience.... But I warn you....I hope you have more patience left... Between all you great guys out there... we will figure this thing out... |
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