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Discussion Starter · #1 ·
I have to start with this because I suspect this may be part of the problem, unfortunately it has an eBay carb:( the carb is clean though and I’ve messed with the air fuel ratio screws and cleaned up the problem a little bit. The problem is when I get on the gas hard it stumbles at the low rpms and cleans up once it revs up. Im curious if there’s a way to fix it with the current eBay carb. I’ll attach link of video of it bogging below. If you have any info please help me out thanks!
Quad is bone stock

 

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02 raptor 686 k&n lexx exhaust
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Ebay carbs are cheaply made so your gonna have nothing but issues. Everyone including myself will say get an oem, been there done that save the hassle. Good luck
 

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oem carbs are hard to get and the ones that are available are stupid expensive. I also agree that oem is better but that doesn’t help for someone that doesn’t have them or can not afford the cost.
That bog/ hesitation sounds like a rich condition that should be able to fix with some time jetting and adjusting the carburetor. Start by lowering the needle (raising the clip) and see if that helps. If it helps but does not fix it you may need a smaller main jet.
 

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Master of the Electron
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The carbs have three circuits that control air/fuel ratio at different areas of throttle:

Pilot jets and fuel screws control idle to about 1/4 throttle,
And coming onto and off of throttle.

Needles control between 1/4 and 3/4 throttle.

Main jets affect from 3/4 to wide open throttle.

Your symptoms suggest an issue with the pilot circuit… the pilot jet orifices are tiny and subject to plugging. I’d suggest cleaning them - Rodding them out with strands of copper speaker wire and spray carb cleaner.

If they’re clean, then test for too rich or lean by turning on the choke fully or partially - does problem get better or worse? Better? Turn out the fuel screws (CCW) a bit… worse? Turn them in.

Also, you must test with the air filter and air box fully intact else you’ll be way too lean.

Keep testing and repeating.
 

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Discussion Starter · #6 ·
oem carbs are hard to get and the ones that are available are stupid expensive. I also agree that oem is better but that doesn’t help for someone that doesn’t have them or can not afford the cost.
That bog/ hesitation sounds like a rich condition that should be able to fix with some time jetting and adjusting the carburetor. Start by lowering the needle (raising the clip) and see if that helps. If it helps but does not fix it you may need a smaller main jet.
Thank you for the info
 

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Discussion Starter · #7 ·
The carbs have three circuits that control air/fuel ratio at different areas of throttle:

Pilot jets and fuel screws control idle to about 1/4 throttle,
And coming onto and off of throttle.

Needles control between 1/4 and 3/4 throttle.

Main jets affect from 3/4 to wide open throttle.

Your symptoms suggest an issue with the pilot circuit… the pilot jet orifices are tiny and subject to plugging. I’d suggest cleaning them - Rodding them out with strands of copper speaker wire and spray carb cleaner.

If they’re clean, then test for too rich or lean by turning on the choke fully or partially - does problem get better or worse? Better? Turn out the fuel screws (CCW) a bit… worse? Turn them in.

Also, you must test with the air filter and air box fully intact else you’ll be way too lean.
Thank you for the response! I ended up buying an oem carb, took it all apart and cleaned it. Just installed it today and it doesn’t idle with the choke all the way off. With the choke half on however it idles fine, better than with choke fully on. Immediately when I turn the choke off it dies and if I’m giving it gas and turn it off it spits sputters and backfires. I know you said pilot and fuel screws effect the idle so should I start there or does it sound like I put something back together in the carb wrong? I have the fuel screws both 3 turns out and I believe the pilots are the same size they came out of the factory with. Again the quad is completely stock except I have the snorkel on the air box removed. I have a video I will try to attach as well.
 

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Thank you for the response! I ended up buying an oem carb, took it all apart and cleaned it. Just installed it today and it doesn’t idle with the choke all the way off. With the choke half on however it idles fine, better than with choke fully on. Immediately when I turn the choke off it dies and if I’m giving it gas and turn it off it spits sputters and backfires. I know you said pilot and fuel screws effect the idle so should I start there or does it sound like I put something back together in the carb wrong? I have the fuel screws both 3 turns out and I believe the pilots are the same size they came out of the factory with. Again the quad is completely stock except I have the snorkel on the air box removed. I have a video I will try to attach as well.
The 2 things I would look at first is do you have any mods (exhaust, open air box, or anything that would effect how well the engine flows) if you do then you may need different jets. If it is stock there may still be more cleaning to do. The passages in these carbs can be tough to clean and it is easy to miss something. I take a strand of wire out of a piece of wire and pass it through all the holes in the jets and anywhere there is a passage in the carburetor while cleaning.
 
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