Weather affecting engine performance?

Zak

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Mar 21, 2019
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70
Yesterday my bike ran better than ever. I was super impressed by its responsiveness, power, and most of all, the fact that if I opened up the throttle it didn't four stroke. I didn't do anything to make it run that way but I did notice it was idling higher than normal. I checked for air leaks, none that I could find. Then later on in the evening the idle wasn't higher than usual and it would again four stroke if I gave it too much gas. I am leaning to believe that it was the weather. I live at about 4500 feet. There was a system moving in that produced some heavy winds... I wonder if because of the air pressure difference my bike had a better air fuel mix.
 


Lukesky36

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Oct 3, 2018
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Could just be some gas in the air filter causing less air to rush in try cleaning it out
 

Tyler6357

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Sep 28, 2011
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638
If you are using the #70 stock jet you could try going down to a 68 to stop the 4 stroking but be advised that these little engines tend to run leaner after they are warmed up and hot.
 

Zak

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Mar 21, 2019
Messages
70
Yeah I need a smaller jet. For now I just control the 4 stroking by being easy on the throttle. I'm not a speed demon. I thought I was but when I recorded a trip my fastest speed was 22 MPH and I went faster than I felt safe at on that run. Just the fact that I'm on a cheap Walmart bike keeps me telling myself, "this is going to break any moment"
 

extremeodd

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Mar 30, 2019
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Just the fact that I'm on a cheap Walmart bike keeps me telling myself, "this is going to break any moment"
Eventually that fear passes, I'm rocking a Huffy 27.5 Parkside that was all of $150 and after about a month of being worried at 25+ I now cruise all day long at 30-35mph and don't even think about it.
 

Tyler6357

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Sep 28, 2011
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Yeah I need a smaller jet. For now I just control the 4 stroking by being easy on the throttle. I'm not a speed demon. I thought I was but when I recorded a trip my fastest speed was 22 MPH and I went faster than I felt safe at on that run. Just the fact that I'm on a cheap Walmart bike keeps me telling myself, "this is going to break any moment"
I understand, but don't worry, it's not going to fall apart. Getting the right jet just helps tune your engine to perform at it's best. They sell jets for these carbs, just get a set and test until you find the right one. ------> https://www.ebay.com/itm/5-Jets-High-60s-5mm-Jet-Set-for-Motorized-Bicycle-Fine-Tuning-Jet-Set/232863070293?epid=1748670011&hash=item3637b87855:g:M5oAAOSwf31bWOj1
 
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Zak

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Joined
Mar 21, 2019
Messages
70
I understand, but don't worry, it's not going to fall apart. Getting the right jet just helps tune your engine to perform at it's best. They sell jets for these carbs, just get a set and test until you find the right one. ------> https://www.ebay.com/itm/5-Jets-High-60s-5mm-Jet-Set-for-Motorized-Bicycle-Fine-Tuning-Jet-Set/232863070293?epid=1748670011&hash=item3637b87855:g:M5oAAOSwf31bWOj1
I wonder if that has something to do with my problems now. Damn thing... I rode it to the store, walked out and had to pedal home. Air filter was full of 2 stroke gas and it wouldn't run fast enough to keep itself going. Ill change the spark plug when I get home and cross my fingers.
 

Tyler6357

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Sep 28, 2011
Messages
638
I wonder if that has something to do with my problems now. Damn thing... I rode it to the store, walked out and had to pedal home. Air filter was full of 2 stroke gas and it wouldn't run fast enough to keep itself going. Ill change the spark plug when I get home and cross my fingers.
What mix ratio are you using? If you are using too much oil it will clog up your air filter and exhaust pipe.
 

Zak

Member
Joined
Mar 21, 2019
Messages
70
I'm using somewhere between 16 and 32 to 1. I will work on it tonight and keep up updated. My spark plug was black and completely saturated. I assume that is what the problem is. In about 3 hours I'll have a good idea. Thanks for your help and tips Tyler. I think ill order that jet kit tonight. I'm using a micargi clone carb ... at least I think thats it. It looks cool and was 16 bucks on Amazon. I guess even with throttle control to keep it from 4 stroking I still need to adjust the.ratio for a dependable ride.
 
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