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Still learning . .. check my theory please

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    Still learning . .. check my theory please

    I solved all my dropped cylinder recharging stuff, checked valves and started back at tuning the carbs. I am ordering the carbtune at the end of the week from England and then have to wait for it to cross the ocean. I want to learn how to trouble shoot and not just be told the solution and not understand why it works.

    I have since used duct tape to seal the top of the air box, I also managed to use spacers to make my airbox level with my carbs and get a good tight fit. They had been canted before and I could see a fair amount of carb body where the boots slip over but all my spray tests didnt show a leak but .. I think they may have been letting some air through. Now they are perfect and snug up against the carb stops.

    Went out for a ride on Sunday for about 30 miles and all was good but the idle seemed off. Just a funky sound that didnt sit right but other than idle the bike ran great.

    Monday I go to the post office and at idle it stalls. I get it home and it will alternately stall or shoot up to 6000 rpm but it wont idle. I figured after reading 1200 posts on it that it must still have a vacuum leak and that my bench sync was off. Pulled the carbs and airbox and found a nipple on the bottom of the airbox that had no hose attached. It was basically letting air right into the carbs after the airfilter. I plugged it up and then looked at my intake boots and one clamp wasn't tightened down properly on the engine side so I tightened it.

    I had oil all around the carb throat where the airbox boots attach and some oil in the airbox !? Hmmmmm Enough that I had to wash out the airbox with soapy water. I still havent opened my airfilter box

    I did indeed not perform the bench sync the first time very well and they were close but not dead on so I redid it and they looked great. I figured what the hell and rechecked all the float heights. They were all fine.

    I checked my muffler clamps just in case.

    I put the whole thing back together and .. it runs worse!! What .. I just checked and triple checked for air leaks and solved three potential air related/vacuum problems. It should be better. So I don't know what possessed me but I put my hand over one of the 2 holes in the bottom of the filter box. Instantly shoots up to 6000 rpm .. pull hand away drops to weird idle. Try it several times and same result.

    So that was the long way to my thinking. I have way to damn much oil on my cleaner element! If covering the hole makes it surge it is because its acting like the choke and enriching the mixture. Now that I have eliminated the other sources of air it really is breathing straight through the filter as designed and its just not getting enough air which is what is causing the alternative lousy low idle and surge. Funny thing though is there is no surging at speed. It is perfectly smooth while driving.

    So does my theory hold. Can surging be produced by not only too much air coming from sources outside of the filter but also from not enough air because of a dirty or over oiled filter element. Is an over happy application of oil on the filter a good guess.
    Alex

    #2
    Over oilling your filter will cause a poor idle as it is making the mixture rich. You do seem to having problems with sealing the airbox have a look Here for a tutorial to help you. It is vital that your carb rubbers are all fitted and tight to eliminate air leaks.
    The big guy up there rides a Suzuki (this I know)
    1981 gs850gx

    1999 RF900
    past bikes. RF900
    TL1000s
    Hayabusa
    gsx 750f x2
    197cc Francis Barnett
    various British nails

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