Motorcycle Club » Star 1100 Classic & Custom

Backfire!!

16 posts from 10 voices
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  1. quinnyim
    #

    I bought my bike about one month ago. It is a 2002 VStar 1100 with 9,000 miles on it. It was running a little rough, so I brought it to the local bike shop. They were going to clean and tune the carbs, but when they got into it, they realized that the carb was outside of the manifold (not in there properly?). They put it back together and said it was running fine. The bike is running a little better, but not perfect.

    The bike tends to run bad when it's cold. It will somtimes backfire when I start it cold. (That may be why the carb was blown out of the manifold). I thought that some gas was leaking into the carb, so I have been turning off the fuel valve. Now, when I turn the key on , the fuel pump runs for several seconds (doesn't do it as much with the fuel valve left on).

    Does anyone know why I might be getting this backfire?

    I should add that the bike has aftermarket pipes on it. I really can't be sure if the previous owner had it jetted correctly.

    Once warm, the bike runs pretty good. I have been having a great time on it (much more comfortable than my 2002 VFR).

    Thanks for any help!

  2. Ravhite
    #

    The fuel pump running is normal, no problem there. You mention having after market pipes, has the AIS been disconnected or removed. If this is still in place then you will have the occasional backfire. One thing that may help the popping when it is cold would be to run some Sea Foam through it on a regular basis......It will help keep the top end clean.

  3. quinnyim
    #

    The fuel pump running is normal, no problem there. You mention having after market pipes, has the AIS been disconnected or removed. If this is still in place then you will have the occasional backfire. One thing that may help the popping when it is cold would be to run some Sea Foam through it on a regular basis......It will help keep the top end clean.

    What is "AIS"?

    I will try some more seafoam. I only mentioned the fuel pump because it doesn't seem to run as much if I leave the fuel valve open. When I turn it off, it runs more. I thought maybe that meant that fuel was leaking into the carb, so it had to replenish it when the valve was opened.

    Will this backfire hurt the engine?

    Thanks Ravhite!!

  4. oltkeeser
    #

    Depending on when the plugs have been changed, you might be able to get an idea of how the carb is tuned by looking at the plugs. With the engine cool, pull the plugs. Google "reading your spark plugs" and you'll find a couple of websites that will show photos of plugs and will tell you a plug that is running rich, lean or about right. If your bike seems cold natured, I'd guess that you are running a little lean, but without hearing it, it's hard to tell.

    If I were you, I'd get a service manual and read up on carbs.

  5. quinnyim
    #

    Depending on when the plugs have been changed, you might be able to get an idea of how the carb is tuned by looking at the plugs. With the engine cool, pull the plugs. Google "reading your spark plugs" and you'll find a couple of websites that will show photos of plugs and will tell you a plug that is running rich, lean or about right. If your bike seems cold natured, I'd guess that you are running a little lean, but without hearing it, it's hard to tell.If I were you, I'd get a service manual and read up on carbs.

    Thanks.

  6. Ravhite
    #

    What is "AIS"?I will try some more seafoam. I only mentioned the fuel pump because it doesn't seem to run as much if I leave the fuel valve open. When I turn it off, it runs more. I thought maybe that meant that fuel was leaking into the carb, so it had to replenish it when the valve was opened. Will this backfire hurt the engine?Thanks Ravhite!!

    Air Induction System: (AIS) Reduces exhaust emissions by injecting fresh air into the exhaust port to completely burn any unburned gases in the exhaust. It works off crankcase pressure and a bladder-type device to pump air into the exhaust port after the mixture has been combusted.

    No, it won't hurt the engine.

  7. drplmgr
    #

    I just disconnected my AIS last night after getting tired of the backfiring. I didn't replace my pipes. but just removed the baffles to get it a little louder.
    At least know the cars hear me next to them.

  8. MidchellNJ
    #

    Sorry for resurecting a dead thread.

    It was posted that backfiring does not hurt the engine. My question is, if the addition of an aftermarket exhaust causes you to run "lean", does that leanness affect the valves? I'm not liking this whole valve adjustment thing and I'm due again in about 2k miles.

    I've installed a set of Cobra Lo-Boy shotguns and there are times where it sounds like a gun goes off starting the bike when cold. I haven't re-jetted yet but still want to ride without concern about the condition of the bike.

  9. wzdartemon
    #

    what type of aftermarket pipes,if its vance and hinces longshots /shortshots then i guess you got the answer

  10. FadMan
    #

    Red-jet it and get rid of the air pump (AIS) - will make a big difference in the backfiring and better power and put the baffles back it - this engine needs them to make the power you want.

  11. quinnyim
    #

    !
    Just an update on a really old thread.....

    I finally fixed my problem. I had the carbs cleaned and they noticed that the original jets were in the bike. I needed a jet kit since the previous owner just strapped on the new pipes without adjusting the jets.

    The carbs were really gunked up, and now the bike starts and runs great. I tried seafoam, but the carbs really needed to be taken apart and cleaned. I think the jet kit probably helped out too.

  12. silverfox39
    #

    I had pretty much the same problem you've described. Cleaning and adjusting the carbs didn't do the trick, so my mechanic installed a new jet kit for me. Problem solved. I haven't removed the AIS yet, but that's next. By the way, I'm also running aftermarket pipes.

    good luck

  13. pill2304
    #

    Air Induction System: (AIS) Reduces exhaust emissions by injecting fresh air into the exhaust port to completely burn any unburned gases in the exhaust. It works off crankcase pressure and a bladder-type device to pump air into the exhaust port after the mixture has been combusted.No, it won't hurt the engine.
    where is the ais located at?

  14. quinnyim
    #

    where is the ais located at?
    This link will show you how to disable it. It is located on the left side of the bike behind the removable cover. (follow the tubes that run along the side of the engine). This method is a good temporary fix, then you can do the permanent fix if your bike runs better.

    vstar1100.com/jack_phelps/vstar/ais.htm

    If you want a really good article on how to disable it with all the pictures, try this....

    star-riders.org/starcruiser/volume4-1/ais_1100.html

    I used this method and it worked great.

  15. LiddleBen
    #

    If your bike backfires through the carb(s) when cranking it cold after sitting all night. You may have a sticking intake valve. Or a weak valve spring that is not closing the valve properly upon the compression stroke. I would try fogging the carbs with seafoam spray per instructions and let it sit overnight. If the valve has carbon buildup this might cure the problem. Also when starting here is how I do it. 1-turn on gas 2 set choke 3 turn on ignition. 4 hit the starter switch. the bike should start fairly easily. donot open the throttle before cranking. it is not a dirt bike. Let me know if this helps. L.B.

  16. quinnyim
    #

    Thanks for the tip. As I mentioned above, a good carb cleaning along with the proper jet kit fixed the problem.

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