Author Topic: Is the stock carb jet to big for high alltitude  (Read 3154 times)

ABslt

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Is the stock carb jet to big for high alltitude
« on: May 01, 2010, 01:25:16 AM »
I bought the scooter second hand, it was in a town from sea level. I live at 6,300 feet the 125 seems I bit  under powered. So is the jet two big, or should I be able to get away with adjusting the air screw
« Last Edit: May 01, 2010, 01:27:25 AM by ABslt »

marioG

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Re: Is the stock carb jet to big for high alltitude
« Reply #1 on: May 01, 2010, 04:46:22 AM »
How do u mean underpowered?

Agility with GY6 is just that, 100kph is just about max limit.

Second hand bike needs checking jet size?

RU Running the bike without problems?

Air screw only works with:

The air /gas screw ONLY affects the idle Mario. You could tweak it a little to adjust for the best setting. They all need this done every so often, but it will not affect the running of the scoot. You could add double the dose of Sea Foam to the fuel. If your main jet is getting varnished, or clogged from fuel additives a couple tanks w/ this may bring it back for you. Also check, and clean the air, and fuel filters. A new spark plug may just be the ticket also. As the plug wears the gap increases, and the performance does drop. Add that to the valve adjustment, and I believe you will be good as new
FUBAR is an acronym that commonly means "f***ed up beyond all recognition/any repair".

ABslt

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Re: Is the stock carb jet to big for high alltitude
« Reply #2 on: May 01, 2010, 06:42:21 AM »
i thought mabye the stock jet was too big for the elevation i am at, id say on flat ground it has about 85kph. Ill have to clean out the carb and give that a try. thanks

marioG

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Re: Is the stock carb jet to big for high alltitude
« Reply #3 on: May 01, 2010, 08:21:24 AM »
thats true....

but power is air and fuel...

if u put smaller jet, equal less power....85kph is maybe problem with standard things...service?
FUBAR is an acronym that commonly means "f***ed up beyond all recognition/any repair".

zombie

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Re: Is the stock carb jet to big for high alltitude
« Reply #4 on: May 01, 2010, 01:15:22 PM »
Hi ABslt, Do give the scoot a thorough going over. Under the general thread there are some links to the service manual. I would also pull the cvt cover to check the belt width/rollers for flat spots, and that all the clutch springs are intact, and working. With a NEW spark plug installed you can do a plug chop to verify the fuel mix at wot. You may find it is running rich, but the main focus should be to eliminate all the basics service issues first.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

ABslt

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Re: Is the stock carb jet to big for high alltitude
« Reply #5 on: May 01, 2010, 03:58:14 PM »
well its got 2k km on it, when i got it i changed engine oil gear oil new plug, adjusted valves, checked tire pressure, the only thing i didnt check was the belt and rollers and so on. Or clean the carb, i was thinking with only 2k km, there shouldnt be problems there

zombie

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Re: Is the stock carb jet to big for high alltitude
« Reply #6 on: May 01, 2010, 09:31:01 PM »
True 2k is low mileage, but you never know how the miles were put on. You can get some more Umph out of it by replacing the rollers w/ 2-3 gram lighter, and replacing the clutch springs w/ any of the after-market sets. How does the new plug look after a few miles? That is the true tell of the tape. If the plug is fouled black you just may need to down jet a size. I would just go 1 size, and mark the performance w/ a NEW plug chop. Ps. Have you done a compression test on it? You should be reading a min. of 120psi when warm.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

ABslt

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Re: Is the stock carb jet to big for high alltitude
« Reply #7 on: May 02, 2010, 03:05:02 AM »
checked the plug, and it looks good nice brown color, did a compression test but it was stone cold and it was only 90 psi, seems kind of low, but that was before the valve adjustment, so will try again warm and after the valves, then i will check back, hopfully its back to 120, if not i guess time for a motor rebuild

zombie

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Re: Is the stock carb jet to big for high alltitude
« Reply #8 on: May 02, 2010, 04:09:42 PM »
Most likely just the rings. I put fresh rings in about 2-3 times a year. A 4t can use them about once a year. Warm does make a big difference tho.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

wordslinger

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Re: Is the stock carb jet to big for high alltitude
« Reply #9 on: May 07, 2010, 03:34:21 AM »
...only 2k????????????...if there is ANY problem you should take it back to your dealer, explain in as much detail as you can what's happening, see what they say, then tell us what they say before you agree to any service contract.........


peace
« Last Edit: May 07, 2010, 03:36:54 AM by wordslinger »
..every mod (action) necessitates a (reaction) mod..

zombie

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Re: Is the stock carb jet to big for high alltitude
« Reply #10 on: May 07, 2010, 04:30:35 AM »
I bought the scooter second hand,   How do you guys make the shaded quotes?   How long did the scoot sit in Someones back yard? They are toooooo easy to fix to throw away. I hope you didn't get scared away by rings! You can still tune the cvt to make it better than when you got it. Just run it around the yard. (or living room as I do) Once it is warm do another compression test. We can start from there.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Shaka

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Re: Is the stock carb jet to big for high alltitude
« Reply #11 on: May 07, 2010, 04:35:34 AM »
I bought the scooter second hand,   How do you guys make the shaded quotes?   How long did the scoot sit in Someones back yard? They are toooooo easy to fix to throw away. I hope you didn't get scared away by rings! You can still tune the cvt to make it better than when you got it. Just run it around the yard. (or living room as I do) Once it is warm do another compression test. We can start from there.

You just hit the quote button in the top right of the post you wish to quote.  To make that part bold I just highlighted it my response and hit the bold button.

ABslt

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Re: Is the stock carb jet to big for high alltitude
« Reply #12 on: May 12, 2010, 01:26:23 AM »
once scooter was warm, i had 125, psi, but now i think maybe i will upgrade the parts, i need to know if the 2009 has the gy6 and i was thinking 2k springs and, 11g rollers does that sound about right?

zombie

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Re: Is the stock carb jet to big for high alltitude
« Reply #13 on: May 12, 2010, 03:48:24 AM »
1500-2k springs, and 11gr. rollers sound perfect. You will find a new respect for your scoot.!
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

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