New to kdx200 need some help

[ranger_5_0]

hi i just got an 87 kdx200 and am trying to get it running properly. ive tried search but i figure ill get more personal responses this was. ill try to provide as much info as possible. also this is my first 2 stroke so maybe i just dont think its right. it seems like power is somewhat lacking in bottom end especially first gear. i hit 2nd and it will pull the front wheel right up. carb has been gone through me about 4 times and a guy i know who actually works at a motorsports shop. stock jetting, needle set on middle clip position. i think i got the float situation squared away atleast it quit leaking fuel out the overflow. it appears there is a part mission from my carb might be part of my problem too. 16065 holder-carburetor, needle jet is the description on the diagram im looking at. im assuming it keeps the needle jet from moving up in the carb body? and it looks like it is made to go between the needle jet and main jet? am i correct? i apologize if some of my terminology is off as im new to this. also i get what seems to be a lean runaway where the kill switch will not shut the bike off but as long as im in gear the bike doesnt rev too high and it will just drive itself slowly, then pull in the clutch and it screams until i dump the clutch in gear to stall it. things ive checked: reeds look good, new petcock, new fuel filter and fuel line, new spark plug, compression at 135psi, supposedly new topend not very long ago. its doesnt start very easily either its about 60 degrees F here and it takes around 10 kicks usually. sorry for the long post just trying to get this all sorted out. edit also not new to working on engines/ carburetors just new to 2 strokes. thanks for any info you can give me.

 

[julien_d]

Wow. That's a lot of information to ingest at once. It's good that you have spent enough time reading and checking the bike to post pertinent questions.

If you just got the bike, I think you need to start at the beginning. Have you checked the compression? Most of the symptoms you describe could be attributed to low compression. I think perhaps this is not the case for you though.

One thing I can tell you for sure, if "16065 holder-carburetor, needle jet" is the e-clip that holds the needle in place it's almost certainly the cause of what you thought was a lean runaway. The needle is staying in a raised position while the slide is closing as you let of the throttle. The engine gets flooded with fuel but not enough air so it revs out but does not produce much power just as you describe. Perhaps the bog in first gear could also be attributed to a rich condition caused by the needle moving up in the slide. You will need to fix this first, for sure. If the symptoms persist after that, then you would start looking for other problems.

 

[ranger_5_0]

no its not the eclip that item is in place. this is on the bottom of the carb where there main jet screws into the tube(needle jet? i think it was called in the diagram) that it goes into. it looks like a small disk maybe the size of a dime or nickel. i figured i would post as much info at first to avoid alot of questions. and as stated in the first post 135psi compression i can see how you missed it though haha

 

[julien_d]

Darn, I thought I had it nailed. Let me look at a diagram and see what you're missing. I swear I read the whole post. I just didn't register the compression. Worn reeds can cause a hard start and some bogging issues. It could very easily just be carb/jetting problems too.

*edit*

I see the piece you mention. It looks like that's what the main jet screws into? Or perhaps it just holds the needle jet in place. Your carb is a bit different from the mikuni's and PWK's that I'm used to. I'd still vote that step one is to replace that part if it is indeed missing. Take a look at the reeds while you have the carb off. You can pull the pipe and get a look at the piston and verify that it is new or in good condition.

 

[sr5bidder]

jullien bro come on after all you been through, does it not sound like sound like he's got an air leak "major air leak" ...Hard start ...sucking air not as much fuel.....reving out with no throttle applied...

..its getting air someplace and if left like this will burn up your "new topend"
Check main seals under flywheel
check reed block and boot to carb
I'd say I'm 95% sure its leaking air into the engine before the carb.

 

[bazmaster03]

i just shouting this out loud but if you mean like a leak in the cylinder the compression wouldnt be high .....but on the other had if you mean like before it get to the the carb or the cylinder i totally agree with what you said
sr5bidder

 

[sr5bidder]

well to be more precise the leak I mean is either at the main bearing seal flywheel side or AFTER the carb and before the cylinder :cool: or both

I would check the reed block/carb boot first

 

[ranger_5_0]

the reeds looked like they were pretty new. not too sure what im looking for there but didnt appear to be any damage. carb boot has cracking on the outside but i flexed it all around and none of them seem to go clear through. main seals under the flywheel i did not check. that would be on the left side of engine correct? will they be obviously shredded or what?

julien: i looked at the piston and it did appear to be in good shape. and that part is not what the main jet screws into as it screws in as is, it is just the holder for the needle jet. the needle jet with main screwed in will just fall out the top of my carb if i turn it upside down. could it be rising due to fuel being sucked up through there thus causing a lean condition since the needle would effectively not be open as far then? just a thought i have some knowledge of how it all works by im no expert. thanks for the help so far i hope i get it figured out soon.

 

[sr5bidder]

Im not sure what the carb stuff is all about but yeah like jullien said get whatever is missing from the carb or a new minkuni carb I know glad2ride has a few laying around.

there is something you can spray on suspect parts ( air leaking maybe) while the engine is running that will change the engine sound and you will know you found an air leak ...might be wd-40

more than likely if there are cracks in your reed block rubber you should replace or at least clean with carb cleaner and skimcoat with black rtv to make certain it is not the cause :blah:

 

[ranger_5_0]

well i finally got to working on the bike again. i made up a piece for the carb just to try and see if it helped. well 3 kicks and it fired right up on choke and actually went to a high idle and continued to run on its own without me touching the throttle. it never did this before i always had to keep it running. so i took it for a spin and stopped up the road and it stalled as usual when i came to a stop. then i couldnt get it to restart i kicked and kicked nothing. so i started pushing it back and about 1/4 mile or so i decided id try again. 2 kicks and it fired right up. seems like maybe an air leak too? im gonna try the rtv silicone on the carb boot and see what happens. hopefully it helps. the piece i made for the carb already seemed to help alot.

 

[glad2ride]

135 is low, so you may want to check on that.

If you are missing a part in the carb, just go buy a new part and install it. It will never work right and no amount of guessing fro all of us will solve a carb missing a part.

 

[sr5bidder]

air leak huh

 

[podfish]

... then i couldnt get it to restart i kicked and kicked nothing. so i started pushing it back and about 1/4 mile or so i decided id try again. 2 kicks and it fired right up.....

===========
Uh, oh - there's a bit of KDX voodoo may be happening here. I've had similar odd behavior out of mine, where it intermittently ran poorly or without power, that seemed to be carburation related. Instead, it was a weak stator. When I replace it with one from RickyStator, all was magically fixed and it ran like a champ.

 

[ranger_5_0]

thanks for that tip podfish. i did order the part for the carb still waiting on it. ill update when i find something out.

 

[ranger_5_0]

a little update here for those that were helping me with this. the carb part was unavailable so i didnt get it. i pulled my stator cover and it was all rusty and water condensed under there. so after fighting the flywheel off (got it off undamaged thankfully) it looks like a mess. now i have a rickystator stator for it but on mine there is only 1 coil on top where it says i should have 2. on the right side looking at it a white/red stripe wire comes into coil then it has a black/white stripe wire going out to a ground eyelet at the hold down screw. bottom coil that i assume is for lighting has yellow/forgot the stripe color coming in and just the copper straight to a ground eyelet at the other end. i spoke with rickystator but the tech was out today and thought maybe someone here might have an idea for me? pics included

*edit* well the tech from rickystator called today and said some of the 87s are weird like that and have just one coil for the ignition side. they are sending me the correct one with a return ups label for me to send the wrong one back. good company. hope this fixes it up