125-200cc Gah!!! help

So i bought a cr 125 a few weeks back. 2004. It felt like good compression kicking it slowly by hand. fired first kick. throttles up good. i took it for a little spin finally and it boggs horribly up any kind of small hill or under load. Im hoping it just needs a carb clean from sitting. maybe sticking reeds? Any easy ideas to keep it simple before tearing the top end fully apart?

Oh but if i feather the clutch and throttle it Will all a sudden lift the front end and rip up the hill

Sounds like the problem may very well be somewhere in the intake. Take the carb off and clean it and make sure the floats are working correctly. Also check te shape of the reed valves. Then fire it up and see if it's any better. If you don't know the history of the bike, you'd be well advised to do a top end job before the top end grenades.

its just jetting - check plug
IM0 it will be rich try adjusting needle to second slot and or leaner pilot
find out settings

Ya the guy knew nothing of the history. i was hoping to get a few rides in before tearing it down. so far i pulled mouse nest from air box :-/ pulling carb now. thanks

AAnd the air filter sticks to the wall if thrown hard enough lol

Internals of the carb are spotless

Did you look at the plug?

Jets appear to be 633? With r-5 below that number and 3.8

Plug is perfectly brown

Its the carb for sure. Spotless inside doesnt mean all the jets are 100% clean inside them,

Jets are clean. i moved the clip up a notch. scrubbed the filter. sprayed out the carb just in case. Will get some fresh mix and give her a test run.

Sometimes jets can appear clean if the measure you are using is seeing light at the other end. They could be restricted and you can't see it by eye-balling them. Just an FYI to consider.

I would check the muffler to see if it is saturated / plugged, it can cause a problem like you describe, and it is only a few bucks to repack.

the jets were shiny inside. plus i sprayed carb cleaner through them for good measure. the muffler does seem to be wet inside, i assumed from the mix. it is sealed though. stock. can that be repacked?

Had the same problem with my 01... repack muffler mine was soaked with oil and water from old owner power washing bike without a butt plug, new packing = less weight+better running!!

I don't have a compression tester... ok so test ride... putting along and roll throttle..BOG....pull clutch. get some rpm's. slip clutch...ZING ...off like a rocket! grrrr

I don't have a compression tester... ok so test ride... putting along and roll throttle..BOG....pull clutch. get some rpm's. slip clutch...ZING ...off like a rocket! grrrr

Just a suggestion, the jetting could be lean at a particular throttle setting. You're riding along and the bike is gradually getting starved of fuel. Then when you crack the throttle...BWOOOOH. You get a lean bog.

Try to identify which circuit in the carb may be lean. If in doubt, try adjusting the needle first as it has the greatest overall effect on running. Drop the clip down the needle to richen the mixture.