Sophomore Rider
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Posts: 196
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Post by newbscootdude on Nov 7, 2014 10:18:01 GMT -5
hey guys so this problem is repeatable and it only happens at rpms over 7k its kind of hard to describe but the easiest description i can come up with is the scoot looses all power at high rpms and will bog when i give it gas when this happens, i have to go down to idle (if it doesnt stall) for a couple secs then the problem fixes itself. it doesnt feel like anything major is happening (like nothing is breaking) if you guys want i can probably make a video of it happening if you guys want to hear whats going on.
and btw the 115 jet isnt rich did a spark plug chop and the color on the base of the ceramic is a lite smoke/tan color however i do get pops when letting off the gas at rpms over 6k which im sure is a lean condition so that could mean i just need to richen up the a/f ratio?
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Post by toddmaples on Nov 7, 2014 14:06:50 GMT -5
hey guys so this problem is repeatable and it only happens at rpms over 7k its kind of hard to describe but the easiest description i can come up with is the scoot looses all power at high rpms and will bog when i give it gas when this happens, i have to go down to idle (if it doesnt stall) for a couple secs then the problem fixes itself. it doesnt feel like anything major is happening (like nothing is breaking) if you guys want i can probably make a video of it happening if you guys want to hear whats going on. and btw the 115 jet isnt rich did a spark plug chop and the color on the base of the ceramic is a lite smoke/tan color however i do get pops when letting off the gas at rpms over 6k which im sure is a lean condition so that could mean i just need to richen up the a/f ratio? Maybe vacuum loss is a factor. Straight line your fuel line To the Carb and try that. Don't forget the cutoff valve... |
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Post by geh3333 on Nov 7, 2014 16:13:00 GMT -5
I love the idea of runnin a straight line from the tank to the carb with a manual shutoff valve on the line . No need for the vacuum valve , it's just one more thing to go wrong . I've had mine like this for about three yrs now . Fuel filter also  |
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Post by geh3333 on Nov 7, 2014 16:45:09 GMT -5
Problem is it can be a number of things , from vacuum to the cdi . It can also be a float issue considering you have to usually give it extra throttle to get up to 7000 rpms and by the time the scoot hits idle the float has enough fuel in it to run again .
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Post by JerryScript on Nov 7, 2014 20:27:38 GMT -5
One other possibility, and you should be able to hear this one: you may have weak or failing valve spring(s). If you hear the valves clatter louder at high RPM, it usually indicates one or both valve springs has weakened, allowing the valve to stay open longer than is proper, sapping you of power. This is commonly referred to as valve float.
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Post by scooter on Nov 7, 2014 22:04:01 GMT -5
I love the idea of runnin a straight line from the tank to the carb with a manual shutoff valve on the line . No need for the vacuum valve , it's just one more thing to go wrong . I've had mine like this for about three yrs now . Fuel filter also That is interesting. For water, 3ft of head = 1.3 psi and 2'=0.87psi and 1'=0.43psi. I wonder how many psi you need to feed these carbs at WOT? I have a tank below the carb, so that option is out for my scooter type, but the one I sold was bogging at WOT with just a manual petcock and no pump running. It had a big open filter so I am fairly sure it had easy flow from the petcock to the carb. I'd guess the bottom of the tank was maybe up to a foot above the carb? Not sure though. |
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Post by geh3333 on Nov 8, 2014 4:02:08 GMT -5
Yeh def won't work with yours . I have bigger fuel line then normal , as long as my float shutoff dosent fail I'll be ok .
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Post by scooter on Nov 8, 2014 4:24:21 GMT -5
Yeh def won't work with yours . I have bigger fuel line then normal , as long as my float shutoff dosent fail I'll be ok . Thanks for the info. If you get a chance, please post the height of your fuel tank, and the distance from the tank outlet down to the carb vertically. I can use that to get psi from full tank to empty and we'll all know more about required fuel pressure for WOT runs. |
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Post by geh3333 on Nov 8, 2014 6:05:54 GMT -5
Yeh def won't work with yours . I have bigger fuel line then normal , as long as my float shutoff dosent fail I'll be ok . Thanks for the info. If you get a chance, please post the height of your fuel tank, and the distance from the tank outlet down to the carb vertically. I can use that to get psi from full tank to empty and we'll all know more about required fuel pressure for WOT runs. I'll do that 2day . |
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Sophomore Rider
Currently Offline
Posts: 196
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Joined: Jun 29, 2013 18:49:49 GMT -5
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Post by newbscootdude on Nov 15, 2014 11:35:17 GMT -5
hey guys so this problem is repeatable and it only happens at rpms over 7k its kind of hard to describe but the easiest description i can come up with is the scoot looses all power at high rpms and will bog when i give it gas when this happens, i have to go down to idle (if it doesnt stall) for a couple secs then the problem fixes itself. it doesnt feel like anything major is happening (like nothing is breaking) if you guys want i can probably make a video of it happening if you guys want to hear whats going on. and btw the 115 jet isnt rich did a spark plug chop and the color on the base of the ceramic is a lite smoke/tan color however i do get pops when letting off the gas at rpms over 6k which im sure is a lean condition so that could mean i just need to richen up the a/f ratio? Maybe vacuum loss is a factor. Straight line your fuel line To the Carb and try that. Don't forget the cutoff valve... its already a straight line gas line i think the gas tank is under the carb so it has the petcock tho. noticed a lot of oil coming out from around either my carb manifold boot or the cam chain tightener. I figured it couldnt be the carb manifold tho theres no oil going through there its a 4 stroke but do u think maybe that could be a problem as well? also i have a friend who fixes up stuff off craigs list then sells them so hes pretty much a mechanic and he told me to run my intake valve at .04 and exhaust at .05 i remember reading a long time ago they should both be at .03 do you guys think i should tighten the valves up to .03? |
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Post by ramblinman on Nov 15, 2014 19:07:35 GMT -5
still not fixed? i would open up the carb and check for holes in the diaphragm.
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Freshman Rider
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Post by ccr on Nov 16, 2014 0:34:31 GMT -5
i had this problem before.
let me guess, it's fine the rest of the time, but when you push it hard after a few seconds all power is gone and it almost feels like the ignition has been completely cut. and it will continue to loose all power until you release the throttle fully and rev it back up again, by that time you have already lost maybe 30km/h speed.
i had this problem before! its carburetor related and i fixed it by swapping out the carb.
it's a dangerous problem to have for many reasons and if it's not fixed it can cause irreparable damage to your cylinder and head
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Post by alleyoop on Nov 16, 2014 0:49:53 GMT -5
No need to swap out the carbs that is a problem with the diaphgram not staying up it is leaking so it drops the needle down and will not recover until it builds pressure back up, that is why it recovers when you close the throttle.
Alleyoop
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(need 112)
..BAD TO THE BONE..