11-13-2020, 05:08 PM
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#1 |
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Join Date: Oct 2020
Location: Central VA
Posts: 1,255
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Brozz 250 Stock Carb Help Please
So i received my jet kit today and promptly removed the stock carb and performed the exact same steps as MotoCheez video.
Current setup: 8 holes in exhaust endcap Airbox snorkel removed 600 ft elevation Adjustments made to carb: Main jet changed from 105 to 110 Added tiny washer under needle Turned idle a/f screw out from 1.5 to 3 turns When i reinstalled and started i noticed now that if i spin the throttle quickly from 0-Full it bogs out badly.. i found that she will only rev properly when i snap to full quickly if i have the choke on 1/2 setting I took her apart again and changed to 108 main and put the a/f screw back to 1.5 out and same thing Lastly i reverted everything back to stock carb settings and same thing.. I did notice that the bog seems worst while riding at stock setting compared to main at 110 and the shim in which it doesnt bog as badly while moving and rpm up a bit. I suspect thats its been like this from the get-go and prob got worse when i removed the airbox snorkel but i havent been full throttling as im still in break in period. Any suggestions would be appreciated.. Would it help to switch out the carb? Might another VM30 off Amazon perform better or do i just have to try again? Thanks |
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11-13-2020, 05:48 PM
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#2 |
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Join Date: Oct 2020
Location: Central VA
Posts: 1,255
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Just read in another thread not to bother with the a/f screw or needle jet and instead focus on the main. I'll try upping from 110 to 115 and see if it removed the full throttle bog while moving..
I read that only a pumper style carb will allow you to spin the throttle from idle to full without the bog, so it sounds like this is to be expected. Will fiddle around and report back |
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11-13-2020, 06:22 PM
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#3 | |
Join Date: Jan 2017
Location: Arizona
Posts: 463
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Quote:
but im using a modified exhaust https://radpaul.weebly.com/brozz-and-hawk-250.html |
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11-13-2020, 07:04 PM
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#4 |
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Join Date: Jun 2018
Location: Florida
Posts: 759
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I'm not aware that it is as common on the Brozz lineup as on other Chinese Bikes, but that said if you have the know how i really would check the valve clearance(s) before i got too far off into beating my head against the carb jet wall, if the valve lash is off it mimics jetting issues but no matter what you do, it won't ever run right .
If nothing else i 'd check the valve lash just to be 100% certain i was starting from a level playing field. Just my 2 cents after having owned and modified more Chinese Bikes than my Wife needs to find out about lol.
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2001 Mustang GT 2004 Sportster 2018 VADER 2020 Orion RXB250L |
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11-13-2020, 07:38 PM
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#5 |
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Join Date: Dec 2016
Location: Argentina
Posts: 756
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No Airbox snorkel, a/f 3 turns out, motorcycle runs better with the choke on. Most likely you are way too lean.
Check for any air leak, if you fully close the a/f the engine should die, if it keeps running for a bit and then dies, you have an air leak. |
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11-13-2020, 08:09 PM
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#7 |
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Join Date: Dec 2018
Location: PNW
Posts: 982
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I would suggest changing one thing at a time, that is a good approach to tuning I learned from a good tuner here on this forum, otherwise you will go all different directions. The goal is to isolate the fuel circuit where the problem is. A very complete description of the problem also helps others help you trouble shoot. You say it bogs but where is it? I bet it is just off idle when you open the throttle? If so, instead of the main I would go up on the pilot jet until it idles well between 1 and 2 turns on the A/F, then try giving it some throttle.
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Linear Mode
