I posted about a week or two ago because I was having a hanging idle issue. Well, I thought that I had that resolved but now I am not so sure that there is not a larger issue here. Basically this started with a simple problem. At 70mph if I saw a red light way up ahead and pulled the clutch to just coast the rpms would drop and the bike would die. The rpms would just slowly decline but instead of stopping around 1200 they just kept going. So I thought maybe my idle screw had vibrated out of adjustment and so I raised my idle speed (my first mistake I believe) then a couple of days later I had the issue with the hanging idle and so I headed the advice I was given: warm up fully and reset idle to 1200+/- 100 rpm and that should do the trick. It seemed to but now I am having trouble starting the bike even though everything else seems right now. The ONLY way I was able to start the bike last night was to screw the idle screw in last night. I tried starting normally at first then I stopped and checked for fuel and full battery charge. Everything seemed fine. I gave it more gas, less gas, choke full on, choke full off. Everything that I could think of I did. The bike was trying to start and everything seemed normal except it would not actually start. Just for my curiosity I reached down and turned the idle screw a half rotation (that is a guess!!!) in and low and behold it fired as if there were no problems. I rode for an hour and a half with no issues! This is the third time this has happened. Sometimes turning the petcock to a different setting SEEMS to help but the idle screw has ALWAYS worked when I have this particular issue.
I am thinking I need to tear into the carbs and give them a thorough cleaning but I am not sure. It was not until the last couple days I could even pin point what I GUESSED the issue was. Thanks for the help guys and your time!!! Sorry I was so longwinded but I wanted to try and fully describe what I know (or think I know) about my issue. THANKS AGAIN!!
Nick
Almost sounds like a vacuum leak or valve adjustment is needed, possibly carb sync too. also have you checked your plugs? how old are they?
I would disassemble the carbs and clean them while looking for possible vacuum leaks. adjust them as necessary (float function/height, idle mixture screw) then sync them. then pull the plugs and check/replace them. if none of these check valves
What do I need to sync the carbs? Also, I have an 02 bike but the Haynes manual that I have is through 99. Will this affect my carb settings or will they be the same as they were? Thanks for the help!! I kind of figured this is where I was headed. I have not pulled the plugs recently so I will look at them when I get off work this afternoon. I can spray starter fluid on the outside of the carbs while the bike is running to determine vacuum leaks?
If I am going to to take the time to clean the carbs, should I order a carb kit and the jets that everyone keeps talking about? What is that jet size, and where is a dependable online retailer for carb kits, bike bandit (any good?)?
In my experience it is next to impossible to work the black art of carb tuning by describing what you don't understand to most of us who barely understand. I have found and am still finding carbs to be difficult. If you have lots of time and not lots of money, now is your chance to learn. Or if you want it to work right now, mail them to buddha or go to a trusted shop.
I started by getting a service manual and a carb diagram. Then read about carburetor theory and how carbs work. Then started with the easiest tests, like spraying with carb cleaner or ether. But just replacing things before you understand why you are doing it is like... um... a monkey with a... no, giving peanut butter to a..., like... won't work.
I read some good books on carbs at the library. I got carb diagrams from bikebandit.com. I searched this forum for a manual. Also I have the older manual and the newer bike and they are 99.9% the same.
if your bike is stock the stock settings should be adequate, not great though. if the bike has any mods at all you should do a rejet, also if you want the bike to run better than stock rejet, talk to Buddha, he can hook you up with jets. but for now I would just worry about getting it running right before modding any thing, it would just bring in more variables at this point.
To sync the carbs you need to buy/make a carb syncing tool. then hook it up, turn the bike on and adjust the throttle bias screws until the vacuum on both cylinders is equal.
yes, you can spray starter fluid to check for vacuum leaks but I recommend looking/listening for one first, possibly while cleaning carbs. if you do decide or are forced to spray you might use carb cleaner, it works just as well but is less flamable (read "less dangerous")
to check the float height first clean the carbs then after reassembly put a tube on the bowl drain and hold the open end above the carb while leaving a kinkless loop under the carb, put the petcock on prime, then open the bowl drain. the fuel will stop at the level in the bowls, if this level is above or below the bowl gasket you need to adjust the floats. what sucks is if you need to adjust them you need to remove and disassemble the carbs to bend slightly the float tab.
It sounds like alot of work but you can do most of it simultaneously. good luck!
Just in case I sounded like a duck, sorry. It is good to try, and good to ask questions, and sorry it sounds like I am shutting you down, that is not my intention. Absolutely take it apart, clean it, see its guts and poke around in there. Try some things and see what works.
Best of luck.
dude, I had the same problem. Even after a valve adjustment, I ended up screwing in the idle/air fuel mixture all the way just so it would idle. Sorry I don't have any advice. Just wanted to let you know I'm in the same boat. Will it idle on one cylinder at a time? I find that mine will idle on the right cylinder by itself, but not the left...
Quote from: Ry_Guy on October 03, 2009, 12:09:09 AM
dude, I had the same problem. Even after a valve adjustment, I ended up screwing in the idle/air fuel mixture all the way just so it would idle. Sorry I don't have any advice. Just wanted to let you know I'm in the same boat. Will it idle on one cylinder at a time? I find that mine will idle on the right cylinder by itself, but not the left...
If you have to screw the mixture screws all the way in to make it idle that means you're too rich for some reason. Very dirty air filter? Way too much oil on K&N filter? Giant idle jets? Sounds like your engine is worn, too. Why you would try to make it idle on one cylinder is beyond my comprehension, but you may have valve problem on your left cylinder. Doing a compression test is a much better way to find out what might be going on.