[boydog40]

installed a new carb, cheaper than installing a carb kit!
will crank and run but when you hit the throttle hard it falls on its face, i have adjusted the bottom screw both ways, little change.
what do i check next?
thanks

 

[Goober]

Rebuild the OEM carb; your aftermarket carb probably doesn’t fit the starter valve and your choke (enrichment) circuit is open. Your plug is probably fouled too

https://www.hondaatvforums.net/forums/honda-fourtrax/119242-trx300-carb-rebuild.html

 

[boydog40]

thanks
rebuilt old carb and she fired right off! has a high speed hesitation. too lean?

 

[Goober]

thanks
rebuilt old carb and she fired right off! has a high speed hesitation. too lean?

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Clean the plug tip with carb cleaner and plastic bristle brush. Old Toothbrush is great

Pilot screw between 1.75 and 2.0?

Start with that idle screw as close to touching but not moving throttle positioner as possible.

Take all the slack out of the throttle cable using the handlebar adjustment screw. Slightly snug the idle screw. May need to choke it to start

Get it good and warm (5 min). You may need to snug up the idle screw a bit more to keep it running. When warm, set idle. Choke shouldn’t be on at this point.

It will be hard to adjust that pilot screw when warm! I use one of those straight insert bits.

Go in a quarter, should stumble, go back out the quarter. Let idle adjust. Go out a quarter, may not stumble but you may see smoke (rich). Go back In you’re good.

You may find you have to adjust the throttle cable at the carb end to provide enough slack at the handlebar end. Just don’t twist the cable while you’re doing it

 

[shadetree]

I just hate it when folks always seem to think the cheap way out will fix things !..lol. stay oem if posb ?, then half your battle will be won !.