JCR125

Member
May 28, 2007
14
0
My Cr125 is bored to 144 and it had a 360 jet in it and it was bogging out really bad...then i changed to 350 still did it, then to 340 still did it...it usually has to be started with teh choke up thats why im assuming it has to be a carb problem...once it starts with the choke up i put it right down it usually idles okay but sometimes dies out...the main thing is when its idleing and then i just twist the throttle all the way and hold it the bike will bogg out and die...and when im riding and hit the throttle it will go "burrrrrrooooopee" and then i let go and gradually hit the gas and it runs okay any suggestions
 

daniboy

Member
May 29, 2007
9
0
i had my kx 60 bored out as well and it did the same thing. when i took it down to the shop they told me it was the jets in the carb.
 

KX250Dad

Member
Dec 4, 2006
204
0
Both our 144's did OK with the Yamaha factory settings 40/410... Once broken in and under race conditions the 410 was to lean and now we're at a 420... and most likely will go 430+. Never did have a bogg issue low end... realize however the bike spends very little time mid/low band. I suspect you may have an issue with the air screw setting, check the book, reset and adjust for throttle response low. Other obvious but assumed OK things are carb air leaks, reed seating, etc., sometimes it's the simple things that'll make us pull out what hair we have left.

Good luck and have fun on your 144 4f killer...
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
Have you checked your plug?Your comments,though colorful,could be a lean condition,especially the jets you are running.That is way lean for a 125,you do not have a manual either!And the lifespan on that mod is about 4 hours.On the plus side a roached motor will run fat till right before it blows,lean for a minute.
 

JCR125

Member
May 28, 2007
14
0
yea ive been through like 10 plugs lol they get real black...but the carb has been cleaned before and it went right back to doing this...i took out my reeds just now and they seem okay except the corner of one on each side is chipped but not enough to cause a gap it still fits over
 
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