kx 125 bogging full throttle ?

 hey everyone i am stumped…. :smashpc:

 

so i rebuilt my 05 kx125 because it was bogging horribly throttle open and needed a rebuild , i ran my bike rich, i cleaned the exhaust valve/port , new piston ,ring, gaskets , all said and done it ran great for 2 rides :thumbsup:   then i cleaned my filter …... it started to prform like crap again ..

no balls at all, i have replaced  the spark plug, reed pedals ( were also cracked ) , muffler packing , cleaned the carb , cleaned the fuel on /off and lines and still no go….   it runs fine ,kicks over fine , but has no balls… some times when i just stop and start from 1st an hold it open i will get that new piston feel and have balls till i shift to second and let off the throttle , once i get back on the throttle   no balls…   i am lost not shure what to think next?  .no balls.. feels like its starving for fuel but it has that ? sometimes it will pull through an i will get real power for a min then its gone and back to put put     any advice or comments would help 

Sounds like fuel starvation. Did you clean the fuel filter and check float height?

if u mean the fuel tap screens yes i have cleaned them , and no i have not checked my float hight yet 

Purchase new pilot jet too

If he's getting choked up at wide open throttle, it would more likely mean an obstruction in the main jet. I had had a similar issue when I bought my KDX, it would only maintain a certain speed while cruising before choking out. Would use up all the fuel in bowl when starting out, then would run out in 2nd or 3rd because the float was too low.

^^ yeah that kinda sounds like the issue and would explain the instant power but  off the bat it preforms like garbage to an runs at 50%  i guess a good way to put it is it bogs off the start an sometimes if im lucky i get power for a bit … so   i guess take apart the carb again or get  a carb rebuild kit ? or just check the float height first  ???  

^^ yeah that kinda sounds like the issue and would explain the instant power but off the bat it preforms like garbage to an runs at 50% i guess a good way to put it is it bogs off the start an sometimes if im lucky i get power for a bit … so i guess take apart the carb again or get a carb rebuild kit ? or just check the float height first ???

New pilot, new main, check float height, new needle valve possibly if bike sat for a while (6 mos.) with pump gas in carb. Most carb rebuild kits do not include correct jets or needle.

Oh ok in most cases, at least for the KDX, you should go a bit leaner than stock jetting for the best response from the motor. If you are higher in elevation you should drop 1 size from factory jetting for every 1000ft up. If you are too rich on jetting it will run like crap

 

In your case a #420 Main and #40 Pilot are the factory jets for an 05. You didn't mention what you are running now but you may want to try a #37.5 pilot, maybe a #410 main. Where is your air screw set?

New pilot, new main, check float height, new needle valve possibly if bike sat for a while (6 mos.) with pump gas in carb. Most carb rebuild kits do not include correct jets or needle.

perfect thanks man , bike never sat ,

Oh ok in most cases, at least for the KDX, you should go a bit leaner than stock jetting for the best response from the motor. If you are higher in elevation you should drop 1 size from factory jetting for every 1000ft up. If you are too rich on jetting it will run like crap

 

In your case a #420 Main and #40 Pilot are the factory jets for an 05. You didn't mention what you are running now but you may want to try a #37.5 pilot, maybe a #410 main. Where is your air screw set?

yeah stock carb,so stock jets and everything, and i think 2 turns out need to check tho

 

 

i will look into all the jeting and check the float height and let you know the outcome , may take a couple days to get the parts tho / thanks guys for the input 

so took it out tonight  with a clean filter ( no oil ) an it made a difference, it felt like i was rebreaking in the bike, so all said an done near the end of the ride it was preforming alot better but still kinda boggy off the start but then il get power an need to push it a little harder to reach full power, also when i hold in my clutch and or release it  i can hear a difference in the motor could the clutch be part of the issue? for loss of power off the start ??

Adjust free play at lever to a nickels thickness. Your clutch could

Be slipping.

**update was the clutch  

**update was the clutch  

 

the clutch was causing a bog? can you explain this?

 

From what I understand, when you lose power due to the clutch slipping, the engine revs higher and does not put the power to the ground. 

^^ Yes exactly 

 

 the clutch was  slipping, and  the engineicon1.png  was reving higher and did not put the power to the ground , but occasionally i got that power for a few mins, then it would make a bogging like sound and give me half performance and sound like shiit 

 

 

the clutch basket was also pootched and crack'd and discs were bad so whole new clutch and it seems to have fixed it but only had 1 ride before parked for winter 

Edited by mason811

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