I have a 03 125 if i just want to hammer on throttle it bogs untill powband kicks in then bog just rebuilt changes plug gas ratio cleaned air filter what else i think the jet or aif fuel is wrong the bike was used for stunt ridind crazy stuff in the air by a pro

there are many air channels in the carbs, witch can be dirty, clean them with very thin wire, and first bled out the gas, check the 2 diaphragms in the carbs

Hi David, bring the high speed screw out until it accepts throttle, regards Phil.

Make sure the carb is thoroughly cleaned, all jets not just main. The half choke is compensating for the slow circuit jet. Check your air/fuel mixture. Also, check the air and fuel filter. If all checks out fine and you still encounter the problem, could be : bad gas, wrong spark plug heat range, or most likely the diaphragm for the top of the carb.

change plug clean air filter sharpen your chain drain the gas replace with correct ratios

Ok I have r Royobi Tiller (30CC Gas) And last year it ran fine after rebuilding the Carb. This year it was "hard starts" Idles fine, (Tiny whisps of blue smoke in exhaust with correct ratio) Even seems to run better with the choke "on" but still...at idle only. as soon as I touch the throttle...its bogs down in tune with how much gas I give it. Little throttle? Little bog down, Little more throttle? Almost stalls, a normal throttle rev? it stalls dead! Then starts right back up again in 1 pull and idles fine again!? WTF? So after cleaning a clean carb again, (twice) and seeing no change I thought I'd go look at the original diaphragm and compare it with the rebuild kit diaphragm (which is the one in the carb.) And guess what? The replacement has a larger rivet by a factor of "2". So basically it was flooding the carb, I bent the needle tang down, better but no cigar. But I could rev it half way now. A second disassemble to bend it yet a bit further and Vrooom vroom vrooom ****! So check your needle valve even though you think its 100%. (Especially if you rebuilt the carb with a kit!)

Also check you plug and the air filter make sure they are both clean and the plug gets nice and red.

Check that your choke is working correctly
Your timing may be way off as well

Jamie it sounds as though you have a fuel delivery problem. What little fuel system there is can be found here: (click "Go")
On the "Handle, Chassis and Bar Assembly" drawing.
http://www.ordertree.com/modelinfo/PWE/2375LE-Gas-Saw-Type-1/75.2375LE-Gas-Saw-Type-1.1.59.1.html
This can be caused by a dirty or loose carburetor, cracked fuel lines, dirty air filter, plugged fuel filter, old fuel mix, and a few more things that aren't coming to mind.

If you attempt a repair take extensive notes and some digital pictures as things progress.

You can get it tuned up for about $40 at a good saw shop (Stihl, Husky, Etc), They do an inspection, change the plug, and adjust the carburetor. Explain your symptoms, ask for an estimate to repair & perform a tune up. If you do this (recommended) ask what oil/fuel ratio they used. Use the same ratio until the next time you have it tuned again. HTH
Lou

Start with setting the air and throttle screws. Turn each one inward until it GENTLY seats. Back each one out one and one half turns. Clean the air filter and starter plunger. The plunger may need to be rebuilt or replaced. Check the pilot and main jet sizes. There will be a number stamped on the side of the jets. The pilot jet should be #45, the main jet should be #140.

hi,this may help,check the inline fuel filter and the air filter,if it has been sitting that long the fuel filter may have gummed up(a slightly gummy residue left behind after fuel evaporates) the engine will run ok at low and medium throttle but the filter will be quite restrictive once the load goes on,change the filter and clean the air filter and you might find the problem disappears...hope this helps...cheers