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Discussion Starter · #1 ·
So, I recently did a carb rebuild an my 300. I did it because the thing didn't rev up all the way, and the vent leaked. So, I rebuilt the carb, and it fixed nothing. I bought some bigger jets, and I'm still playing around with it. But as for the vent line, I can't get it to stop leaking. Any ideas?
 

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What carb kit did you use? I use Shindy, K&L or OEM.

It’s either leaking from the carb drain screw or the float valve.

Inspect carb drain to make sure the seals are in place.
Font Audio equipment Gas Electrical wiring Cable

did you clean the float valve seat? Gently swab it with a cotton swab and carb cleaner—you don’t need to use abrasives. Manual says be careful not to scratch the seat

buy a new OEM Honda float valve and consider replacing the float.
 

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Discussion Starter · #3 ·
I used a quadboss brand. But I believe I fixed it. The brass tube at the bottom of the bowl had a small leak, so gasoline would run down it. I had an extra bowl laying around, and it fixed it.
 

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Yeah good deal.
You can try soldering over the crack or resoldering the pipe. Just make sure there’s no fuel vapors or you could lose your eyebrows
 

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Discussion Starter · #5 ·
Haha, wouldn't want to do that. And I don't think it's worth it, considering the bowl is pretty pitted, and I had a non-leaking bow already. But I thank you for the tip.
 

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Discussion Starter · #6 ·
I am having trouble with my carb jetting. I have a 140-size main jet in it and can't get it to rev up all the way. It's super close, but I can't get it to go anything past. I keep playing around needle and jet size, and I can't get anything to work. I can't tell if it's running lean, or rich. Based off my symptoms, are you able to tell?
 

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Andy I recommend you put the stock jets in it. Ensure your pilot jet setting is 2 full turns out from lightly seated.

What color is your spark plug?

it sounds as if your carb isn’t synchronized properly.

Did you replace the choke valve?

remember that carb has a rubber vacuum piston. Can’t have any holes and piston must move freely

Check If your throttle cable or thumb throttle moves freely all the way open.
 

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Discussion Starter · #8 ·
It idles great, choke works fine, and the plug is a bit black, which tells me a bit rich.
 

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Discussion Starter · #10 ·
I actually started to mess with it and found out that the boot that is on the motor side of the carb was split. This means the motor was sucking air through that split, which in effect, producing a leaner mixture. So, I took the boot off and glued it, and put the stock jet size in it, with the needle in the middle position. It's running very well, but not at peak performance. One notch up, too lean, one notch down, too rich. So, any ideas on what I could do to improve the top end performance? Would a new spark plug help? new fuel filter? Maybe adjust the valves? I don't think so, because the motor was just rebuilt in November. If you have any suggestions, let me know. Anything's worth a shot.
 

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How do you know it’s falling short on performance? These are meant to be nimble and lightweight—not racecarts. Mine goes maybe 21 mph.

I would also replace the insulator oring #24

Product Font Line Parallel Screenshot
 

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Discussion Starter · #12 ·
I did replace that o-ring when I did the rebuild. When you hold the throttle wide open, it doesn't quite rev up all the way. I could be just being picky, but I don't think it's properly tuned. I do want to put a new spark plug and fuel filter in it and see where that.
 
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