Full tank = better starting

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Full tank = better starting


Post by panfreak » Sun Aug 08, 2004 1:12 pm

Please tell me I'm not nuts. Am I the only one who's bike seems to start better on a full tank? Maybe it's Newton's Law, but it seems that when I'm down around 3/4's empty it's not quite as consistant when starting. When I'm full it's almost ALWAYS a first kick bike. What the f^ck is going on here? I don't think it's a venting issue, I have no problem that way when running the gas down on a long ride. I'm hoping someone will concur with my suspicion that just maybe gravity is helping to force fuel to carb.
And another thing about venting; I read somewhere that to tell if your cap is vented, put your mouth on it and blow. Sounds simple enough... has anyone actually tried this method? I know I got a big mouth (no pun) but there is no friggin way I can get my yapper around a gas cap! But there was this girl I met in a bar once....... ;)

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Re: Full tank = better starting


Post by mbskeam » Sun Aug 08, 2004 7:41 pm

well I dont think you are nuts, as mine is kinda like this also
if its on res. it can be hader to start
I did find that the pin that holds the float on the MIC is a bit loose, the body of the carb has worn from milage (vibration)
next time I have it apart I will fix it by using the drill bit end from the drill bit I use to clean up the holes in the body....
or I could try out the linkert,not sure yet

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Re: Full tank = better starting


Post by BigMike » Sun Aug 08, 2004 10:45 pm

Check your fuel line routing as well, if line runs too high you could end up with an air bubble when it's on the sidestand, a kink could also slow down the fuel delivery if there is less fuel in the tank to force it through.

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Re: Full tank = better starting


Post by rigidpanman » Mon Aug 09, 2004 10:10 am

freak,i know on my cap you can hear the vent "ball" rattle around when you shake the cap.

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Re: Full tank = better starting


Post by King » Mon Aug 09, 2004 6:07 pm


No you're not nuts, mine does the same thing. Why? I have no clue.
But I do have venting problems when the tanks get low if I use my standard caps (Rt vented, Lt not vented). I get around this by replacing the standard cap with a cap from the tractor supply place with two holes drilled in it on the left tank when the gas level is down.
My vent test is to place the whole cap in a shallow pan of water and blow air from one of those electronic cleaning cans (with the straw) through the internal holes and see if it bubbles up on the part of the cap that is outside the tank. I was surprised to find that one cap I tested that looked vented wasn't.


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Re: Full tank = better starting


Post by panfreak » Tue Aug 10, 2004 6:56 am

No my lines aren't kinked or run all over the place, I am very anal about my tube bending. And I shook the caps like an idiot in my shop last night, I heard nothing other than those damn voices. I couldn't afford nice old eaton caps so I opted for repo (God help me) and I suspect they aren't vented at all. I must be getting air leaking around the cap(s) because I don't build up a vacuum on long rides, all goes well. I am gonna stop worrying about those caps and just go with the flow, so what if I have to kick three times when low as opposed to just once?

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Re: Full tank = better starting


Post by TANK » Wed Aug 11, 2004 11:10 am

Instead of shaking yer caps , there is a post here,(can't find it now)
that said, to simply suck on the cap, if it's vented it will draw air..
How simple is that ??& fool-proof~

I tried this on my ride, it works.
It is only a 1 way vent allowing air in, so if you are blowing out it should not blow any..

Just IN...

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Re: Full tank = better starting


Post by dirtpandan58 » Wed Aug 11, 2004 8:32 pm

Have you tried loosening or taking one of the caps off before you start it on a low tank?

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