here's my input about the situation I had with my kx500. The piston exploded while riding , I sent it out to a notable builder to rebuild it. Got It back in the frame and it wouldn't idle. also, tons of smoke every time I started the bike. Cleaned the carb to perfection, still no idle... I even bought a brand new keihin carb from Keihin and was heart broken when it too, wouldn't idle. I thought it might be related to the exhaust system so I purchased a brand new pro circuit pipe and silencer. still no improvement. Progress was achieved when I took the time to do an air leak test. bought a freeze plug to seal the exhaust port, put a plate on the intake port and pressurized the cylinder through the spark plug hole. sprayed soapy water and found a massive air leak at the power valve rod. The builder neglected to replace all seals as I had requested. So in my opinion, this air leak probably played a part in why the piston failed to begin with. So I ordered a complete gasket and seal kit and replaced the top end seals and gaskets. Once together, the bike STILL failed to idle.... idle screw all the way in, multiple jetting configurations....still wouldn't idle. Now I'm getting upset and convinced myself to just completely go through every possible thing that could be causing this. Thankfully I started with the right fix.... I started by measuring the fuel level in the carb referred to as "fuel service limit". The fuel should be slightly below the carb seams... I bought an aftermarket carb drain plug, drilled a hole in it, stuck a 12 inch length of clear tubing in it, and installed on the bike. I opened the petcock and measured the fuel level and I discovered it was about 10 mm above the carb seams... it was getting too much fuel in the bowl. I bent the float tab accordingly and brought the fuel level down to 1 mm below carb seams and bingo... bike immediately idled. Way better power . It runs great now. So the lesson I have learned and would like to pass on is to do these tests and they will save you a whole lot of trouble.
I seem to be having the same problem on my 01 kx 125. I haven’t done a leak down test on it but I did the rebuild myself and was a bit confused putting the power valve back together so I’m thinking that is one of my issues because I have load engine knocking noises at low idle then dies off. I cleaned carb aswell and even got the jd gasket kit for the mikuni (say it fixes idle problem) and it didn’t! I didn’t even think about the float!!! But I’m gonna try it tomorrow hopefully she idles and stops the knocking at low idle🤞🏻 Thank u so much for this comment I’ll get back to see if it worked for me or not.
I didn't hear a bog it just died but my 85 does the same thing runs good but don't like to idle so I just turned Up the idle screw and adjusted the air and gas screw a little bit in and it runs and idles great now
so when your choke is on you shouldn’t have to “prime”. The choke is allowing for more fuel and less air into carb. No choke then you want to throttle when starting, also the need to kick to build compression before starting is a sign of worn rings or piston. Got to address that first. Also your air screw is important for closed to 1/8 throttle opening.
In what world is that even priming it? There is no fucking prime and you can twist that throttle all day isn’t gonna pull gas up unless the bikes under vacuume aka running.
ben selby I rebuilt the entire engine and rebuilt the entire bike basically and now I use is castor 927. I used to use Lucas 2 stroke oil and it’s not meant to be mixed at 32:1. But that solved it and I will never use anything else
I see that you have the same carb as the one I have on my 2004 yz 85, I cleaned it and put it back together and I couldn’t figure out where to feed the fuel lines from the carburetor. So I fed them all to the bottom end it rode for a little while then one of the tubes was leaking gas and it could hardly move. If you could help me that would be great
What do you mean load up? Do you mean gumming it up? My buddy just got a KX112 and it won't idle but otherwise runs good. The dealer told him they set them that way so people don't let them idle too long for that reason. They would rather have you blip the throttle to keep them running. Keeps them cleaner.
@skipperjones7490 Gotta keep revvin 2-strokes or ya foul spark plugs. Can't putt around like a four-stroke! I grew up ridin/racin 2-strokes in late 80s & 90s but prefer modern 4strokes. Also make sure ur pre-mixed fuel never more than few wks old! Just mix what u will use. Gotta be fresh! Maxima 927 is best 2stroke premix oil hands down.
@skipperjones7490 Yea 2-stroke idle should be set up so engine dies if not blipped etc. Use good octane booster in premium pump gas + Maxima 927. Pick a premix an stick to it or gums up jets. -SE Michigan
‼️PLEASE ANSWER ANYONE‼️when i turn it up a lil bit and im in 1st gear the bike still moves and it wont come to a full stop and when it does it turns off. I just got a drz125L yesterday
You should never rev it when it’s on choke it should run good on choke it should never do that I had the same problem first I fixed the idle screw quickly
@@isaacwilliam8149 everything inside is fine got fresh parts and oem jets for it. Still no luck. Even with the idle set high it still wants to die. I want to adjust the needle but not sure if I should do that first
