Idle mixture adjustment (air OR fuel screw adjustment) Carburetor

Carburetor problems? Bike have a bog when twisting the throttle? Here is how to properly adjust the mixture.

2:20 this is an edited shot, 2 turns is just an example, your results may vary.


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Chapters
00:00 Adjustment screw locations & explanations
0:43 Initial idle mixture adjustment & general guidelines
2:33 Adjusting idle mixture with the engine running
5:34 How to know if pilot jet needs changed

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How to adjust the air or fuel screw on a typical motorcycle or ATV #carburetor. Typical procedure to adjust the idle #mixture on a carburetor. First thing to do before #jetting the carburetor

[thejunkman]

Also, this has caused some confusion over the years PLEASE READ:
2:20 this is an edited shot, 2 turns is just an example for this demonstration, your results may vary. A turn is defined by 360 degrees

[gerryhost]

I swear you worded this better then anyone ive ever heard

[thejunkman]

I am glad you learned something and got your machine running like you want. This is why I make videos.

[TrentMRobertson]

Thanks for providing the simplest, most informative carb adjustment video on YouTube.

[erwinpadgett]

Thank you for all the information you did in this video. Clear, precise, and great video with details included. This helped me greatly with my problems. Need more people to do videos like this one!

[daniellepotts]

So glad I found this video...  Thank you so much for your time to new comers of the pit bike sport.  I just bought a new SSR 160TR pit bike. It came with a generic manual that is so old it does not even match the pics of the parts.  I believe It had a Minuki 26mm carb.  From your video I relized it has an air screw adjustment.  My problem is, at Half throttle is boggs down and can get out of its own way.  I have to gingerly ease the throttle on and nurse it to get the bike running strong again.  I followed your video and found that the air screw was set at 4 turns out.  So I used your method of finding the sweet spot and it is about three and 1/2 turns out from full seat. I did not look at the needle jet or an other things since the bike is brand new.  PLEASE PLEASE PLEASE give me some advice.. Again, I have read your spec sheets as well as your videos but I am stuck..  The dealer said I just need to choke it and clutch it..  which I think is BS..  Please respond.. Thank you- Jeff

[thejunkman]

If this video helped you out, consider giving a "THANKS" ❤ To help fund more videos like this!

[TheExcessivemhz]

This video made me able to completely understand carb adjustment. Excellent tutorial. Thanks

[nacsmxer]

Excellent and very informative video. This helped me a great deal in dialing in two different machines (one has an air screw and the other a fuel screw). They were in the ballpark before but now it's close to spot on. Thanks Junkman!

[thejunkman]

Ahhh, the magic of editing my friend. This has been brought up numerous times. Notice the crossfade indicating a jump ahead in time.

[thejunkman]

👋💡 2:20 this is an edited shot, 2 turns is just an example for this demonstration, your results may vary. A turn is defined by 360 degrees

[scottadkin]

Great Video, replaced carb on old 49 cc Honda with Chinese pit bike carb, followed your tips on air speed screw and moved the needle jet 1 notch leaner, the bike runs fine, thanks for your help.

[noelone]

This is the best way put I’ve seen on YouTube. I’ve seen at least 10 different videos. This should be at the top of suggestions

[GreatBritishBeans]

Very well explained! gained a subscriber!

[Tatorhead]

but you only turned the screw half a turn not 2 turns

[grahamwilliams]

Thank you! Nobody ever mentions blipping the throttle to check for hesitation. I’m gonna try this today to see if I can fix the hesitation issue on my quad

[thejunkman]

Head on over to my website (link in the description) check out the comments section as this question gets asked a lot and I have answers over there, plus more videos that may help OR ask you question there and I can possibly help diagnose your problem. You can comment as a guest without having to register.

[crazycarpes]

For me its a total new way to set the idle !!! Thanks man! It works great on my carb!

[surlybonds]

Just want to say you did a great job explaining this concept on the video. Well done and very helpful!

[papajoeknows]

Wow, thank you so much… I’m not mechanically inclined (more like mechanically disabled). I barely knew where the carb even was, but you just solved my problem… my antique 1969 Honda trail 70 is purring like a kitten now. 👍🏻👍🏻