Leaning bike to the left kills it - Page 2
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  1. #11
    Senior Member asdfqwer426's Avatar
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    548
    Quote Originally Posted by Twowheelrich View Post
    I have the same problem with my Dohc 450. When on the side stand, the idle will smoothly drop until it quits- takes about 20 seconds. I *imagine* it has something to do with the floats hanging up and causing a rich condition, as Steve suggests, but I've learned to use the center stand when I can't prop the bike on the slope.

    The slope I'm referring to is the uneven gravel approach to my garage, and the only time this problem occurs is after a spirited ride locally and I'm off the bike and opening the garage door. If I'm quick, it won't stall. If I park it across the slope the bike stays more vertical and the idle is more or less constant. I think it's also dependent on how hard the motor's been worked at the tail end of my ride, when it might be hotter than normal. I never leave it idling otherwise, and only do so during a cold start.

    Next time I give it a tune up, I'll check for cam 'shift' when I'm adjusting the cam chain tension, but that'll be a while.

    I should add that my shocks are about an inch longer than stock so the bike will lean more while on the side stand. With the stock sized rear tire(when new), the center stand barely gets the tire off the concrete pad in my garage but if I use a 1/4" 'shim' The tire has plenty of clearance.

    Steve's theory about the cam shifting is intriguing and I wonder if it somehow affects the advance mechanism, and not just the points...

    Hey Twowheelrich, I just wanted to mention that the 450 differs from the 350 in that it's carb uses an eccentric float chamber compared to the 350's concentric float chamber. basically, almost all bikes have two floats positioned equally on either side of the carb jets. this makes it so when you tilt the bike, the floats more or less balance each other and keep fuel level in the carb even at the jet. or it's supposed to anyway. The 450 however has only one float on one side of the carb. tilt the bike one way, fuel level in the bowl goes down making it a bit lean, tilt it the other way and it goes up making it a bit rich. This is probably what's going on when you tilt your bike while idling. my 500t has carbs the same and also does this when on the side stand. As steve mentioned, when you're rolling the centrifugal force keeps it all even.

    If you haven't seen it, there's a manual made by honda in 1975 called simply "honda motorcycle carburetion", frequently labeled as "carburetion 1975" online. it's a pretty good read and really explains lots of carb systems really well, using honda's carbs from their 70's lines of bikes as examples.

    next time you get to that tune-up, the 450 cam should have a clearance of 0.05-0.35mm on the side according to pg.26 of the factory service manual. Less and it can bind, more and it can effect the oil pressure.
    Nick

    CL350 K4
    CB500T cafe (w/ suzuki pistons)
    CB360T

  2. #12
    Senior Member Twowheelrich's Avatar
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    Nov 2013
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    Lookout Mountain, Georgia
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    143
    Thanks, Nick. And, if you think you just read a response other than what you are reading right now, you are not wrong. I'm working on a GL 650 right now and got the two confused, and just deleted it.
    Last edited by Twowheelrich; 07-04-2019 at 05:49 PM.
    1973 CB450
    1968 CL 175
    1991 KLR 250

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