KX Riders
Maintenance & Technical => KX500 Original => Topic started by: khaavet on February 23, 2009, 12:32:59 PM
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so here is the story i bought a kx 500 1990 bike was 100% stock owner had it since it was new.all he ever did was change oil clean filter new chain and tire and put a 15 tooth gear up front and he had changed the rings once.so i took the bike out and was not happy bike ran good WOT but had a hard time getting the front end up Yes even in low gears 2,3,4 so i tore into it replaced piston,rings,reeds,sproket in front to a 14, redid packed silencer. and still it seems like the bike is very boggie and kinda dead on the bottem end like i have the choke on. now i am changing the clutch as we speak (about time after 19 years) so my guess is one of 2 things my jetting is off (set at stock 168 main 60 slow clip at 3) or my cylinder is totally shot (did not have any freddie couger marks in it looked good) any body have any good ideas
thank you :? :? :? :? :? :-P
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Are the power valves working properly?
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I think so what is the best way to check thank you for the input
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I think so what is the best way to check thank you for the input
It's just a slightly "educated" guess.
The last time the previous owner did a top end, he likely didn't get the power valves back in correctly....backwards is very common.
Good way to buy a cheap bike with only a minor problem, though. LOL
If I just did a top end and the bike didn't run right...I would assume I got the power valves in wrong.
Best way to find out...yank the top end and check the power valves.
If they don't work right, the bike won't run right.
Even with a horrible cylinder and some carb probs, that bike should still pretty much run like a raped ape.
Unless you are at a way different altitude or something....jetting all by itself shouldn't make the bike run that bad.
If it's easier,.....make sure there is no schmucky stuff in the carb.....and make sure the screen in the petcock is clean of schmuch from sitting.
I could tell you 500 things to look at after all the work you did....but my first thing would be checking those power valves....other then simply going over the extremely obvious....air/fuel mixture, etc. stuff that could have been done wrong when either you or the previous owner tore it down.
Stuff happens, ya know...the phone rings, whatever.
Go easy when you pull the cylinder and you might be able to reuse the base and head gaskets.
What does the spark plug look like? Look at it and smell it.
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The spark plug is wet and smells like gas. If I take off the pipe I shoulde be Abel to c the power valves and see if they are installed correctlly right? They are closed when the rod is pushed all the way in and open when the rod is pulled out. How can I check if it is working when the bike is running. Sorry kinda new to this kipps system.
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The spark plug is wet and smells like gas. If I take off the pipe I shoulde be Abel to c the power valves and see if they are installed correctlly right? They are closed when the rod is pushed all the way in and open when the rod is pulled out. How can I check if it is working when the bike is running. Sorry kinda new to this kipps system.
Yeah, duh....you sure could.
Ok....then check and see if it operates smoothly.....before you even pull the pipe.
You need to determine if it's working.
It's an "educated" guess on my part, based on a short blurb you put up.
When you did the top end....did you look at the power valves?
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so here is the story i bought a kx 500 1990 bike was 100% stock owner had it since it was new.all he ever did was change oil clean filter new chain and tire and put a 15 tooth gear up front and he had changed the rings once.so i took the bike out and was not happy bike ran good WOT but had a hard time getting the front end up Yes even in low gears 2,3,4 so i tore into it replaced piston,rings,reeds,sproket in front to a 14, redid packed silencer. and still it seems like the bike is very boggie and kinda dead on the bottem end like i have the choke on. now i am changing the clutch as we speak (about time after 19 years) so my guess is one of 2 things my jetting is off (set at stock 168 main 60 slow clip at 3) or my cylinder is totally shot (did not have any freddie couger marks in it looked good) any body have any good ideas
thank you :? :? :? :? :? :-P
does it surges @ bottom end,could be the mainjet ,60 could be slightly to big.
i am at sealevel and my k5,s have 58 main
what premix ratio u run ??
does it smoke excessive?
The spark plug is wet and smells like gas. If I take off the pipe I shoulde be Abel to c the power valves and see if they are installed correctlly right? They are closed when the rod is pushed all the way in and open when the rod is pulled out. How can I check if it is working when the bike is running. Sorry kinda new to this kipps system.
thats no good ,plug should be dry and tan colored.
for check on the kips there,s a tun of knowledge bout kips ,its valves and rods ,allen bolt mod etc:
utfs :wink:
for valve operating check:
remove the expansion chamber that sits at the base (right side cyl)
it,s the little grey cap ,take it off ,start the motor ,give it a few revs ,
best done when warmed up allready btw.
you will see the rod come out when you rev it,and it goes in when you let go of the throttle
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okay guys thank you i will check and c if the kips is working right waiting for my new clutch now shoulde have it in a few days. i am running 40:1 ratio at 2500 to 3000ft above sea level so im sure my jetting is way off being that im running stock jetting at 168 main 60pilot jet and 3 on clip waiting for new jets i got a 165 main 55 pilot and i will put the clip at 2nd from the topp i hope this will work i cant wait to feel the widow maker power :lol: :lol:
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It won't be a widow maker if you speak nicely to it at all times. :-D
Ok, back up a few steps....can you tell me why you just bought a bike....rode it, it was experiencing some serious performance problems....and you're first thought was to tear it all down rather then give the guy you bought it from a knuckle sammich?
Did you get it super cheap....did the guy you bought it from tell you it didn't run right?
Fill in some details here.
What was wrong with the clutch?
This is not a 4 stroke...and it is a bike/motor that will run almost no matter what. A minor jetting problem is not going to make the bike behave the way you are describing. It might sputter and burble, whatever....not run well....but it'll still pick up that front end with a crack of the throttle.
It may sputter, sputter then wheelie and scare the do-do out of you....but it'll still wheelie. :-o
I used to live at 7000+ ft.....2-3K won't make that much of a difference. Not enough to make the bike not run.
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well ibought the bike for 850 dollars so i think that is a good deal the guy i bought it from did not know about bikes. like i said he never changed the clutch in 19 years so i think that it is fried all he ever did was change the rings once about 10 years ago this bike was riden about 15-20 trips per year so it got a fair amount of hours on it. i think it is a combo of things the kips may not be working correctly the jetting is off the clutch is bad so i have to do the jetting check the kips change the clutch after that has been done the only thing i can think off is that the cylinder is done and needs to be re plated
what do you guys think? :?
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No power on a two stroke, the first thing I'd do is check the compression. The thing should still wheelie even if the KIPS is not working. It ain't a Honda 70 ya know?
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okay so other then feeling the pressure on kick starter how do i measure the compression in the cylinder is this something the dealer needs to do for me
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No power on a two stroke, the first thing I'd do is check the compression. The thing should still wheelie even if the KIPS is not working. It ain't a Honda 70 ya know?
i had kips disfunctioning once ,i immediately noticed 50 % drop of power ..
had to re-connnect the lever to the rod ..did it and there was the power again.
okay so other then feeling the pressure on kick starter how do i measure the compression in the cylinder is this something the dealer needs to do for me
they make gauges for compression testing
pull plug ,insert nozzle of the gauge ,then kick the hell out of it.
all with cold engine ,kick untill the meter settles ,that,ll be your compression
don,t have the shopmanual here, but search for the in spec. numbers
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okay thank you guys i will try the kips first then if that does not work i will go the compression route
crossing my fingers and hoping for som widow maker power :-D
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well ibought the bike for 850 dollars so i think that is a good deal the guy i bought it from did not know about bikes. like i said he never changed the clutch in 19 years so i think that it is fried all he ever did was change the rings once about 10 years ago this bike was riden about 15-20 trips per year so it got a fair amount of hours on it. i think it is a combo of things the kips may not be working correctly the jetting is off the clutch is bad so i have to do the jetting check the kips change the clutch after that has been done the only thing i can think off is that the cylinder is done and needs to be re plated
what do you guys think? :?
Ok, there were more posts while I was typing.
After reading your response, my best advice to you would be to buy a manual...Clymer is very good....and ask a local friend with some mechanical knowledge to help you.
It is likely that getting help on the internet might not be the best way to get your bike running well. It's not an insult, just advice.
A compression test gauge can be bought at most auto parts stores...it will come with instructions....read them thoroughly before you even start.
It would be a lot easier to have a friend help with the process. It's not impossible to do by yourself....but it is far easier with an extra pair of hands.
Anyway....good luck to you.
peace,
janette
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well ibought the bike for 850 dollars so i think that is a good deal the guy i bought it from did not know about bikes. like i said he never changed the clutch in 19 years so i think that it is fried all he ever did was change the rings once about 10 years ago this bike was riden about 15-20 trips per year so it got a fair amount of hours on it. i think it is a combo of things the kips may not be working correctly the jetting is off the clutch is bad so i have to do the jetting check the kips change the clutch after that has been done the only thing i can think off is that the cylinder is done and needs to be re plated
what do you guys think? :?
Ok, there were more posts while I was typing.
After reading your response, my best advice to you would be to buy a manual...Clymer is very good....and ask a local friend with some mechanical knowledge to help you.
It is likely that getting help on the internet might not be the best way to get your bike running well. It's not an insult, just advice.
Anyway....good luck to you.
peace,
janette
buying the manual is indeed first prio i,d say too.
but in the mean time there,s a great deal of knowledge about the k5 here ,its kxriders after all..
and for those who don,t have a database of years of racing ,it has been very helpfull
this is not just (the internet ) but more off a big extended family affair where help is in every corner .
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okay thank you i will do that
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anybody know what the compresion shoulde be?
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use the search :-)
then you ,ll find the info .
i searched and the manual says min.105 psi max 164 psi
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Yeah, I agree that 60 could be fat. Plug should be dry and tan after running. If it needs rebuilt, though, and she smokes alot, all the time, crank seal would be worn. Then she would be sucking oil and giving you a rich reading on the plug. If you can start it without boots, it needs a top-end. The right thing to do is pull the top-end and check your cylinder plating, piston condition. There's an excellent post on piston color and appearance reading, just like the one on spark plugs.
You should be able to get the power valve cover off, and watch it work. When the engine revs, it comes out like an inch. Sometimes carbon and oily goop hold it up and choke off the power. Usually you can get it free, but its full inside. If its just a little stuck, you may be able to go rippin' and help it. I'm guessin' its that powervalve, or if she smokes like a smoke bomb, then its crank seals.
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I need your input for the big 1's on my Plate!!!!!!
Old school dirt track numbers. :-D
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Okay here is an update new clutch installed 165 main jet and 55 pilot checked kips working good big diffrence big has slot more power to the ground frontend comeing up like it was going out of style on the street anyway still need to do commpresion test but bike does not seem bogi on the low end can't wait to take it to the dirt finally I get to feel the k5 power :-D
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well i went rideing today and im not very happy with the way this bike is still not running right need to check compression any body have any idea what is wrong here have done new clutch jetting is right new piston and rings kips is working
only thing i did not do was to overhaul the cylinder (never been done since it was new 1990) bike seems like it does not have power front tire is not comeing up even on hard packed dirt unless im in 1st gear what else can it be other then the cylinder?
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Its running good, but no wheelies? You have a new tire on it? Nobbs need to be square cornered, or it will spin alot on dirt. What gearing are you running?
Its blubbering still, like the choke is on? Does fuel come out of overflows? Overflows are clear and free flowing, if they needed to overflow? Floats stuck, out of adjustment or worn parts can flood mixture. Reeds not sealing with warped or broken petals can cause funky problems with power too. If they are junk, I suggest finding some Vforce. 5.5 average hp gain bolt-on, according to their paperwork. Good reeds help the mixture be true. I had broken petals, once and it started fine, but had no power. Other times they will have power, but not run on low end. Worth checking out.
Does it come on the pipe at some point? It should be stretching your arms or be squirrely, when turning it on. It can get to the top of the rev quick, but should be alot to handle in third. If not, something is out of tune or low on compression. It has "widow maker" power, you're at the right place to get it to make that power. Good Luck
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the reeds are brand new. but a wierd thing happend when i started it the first time in the desert for about 2 min i was leaking gas out of the over flo tube what is this? then i went away. as far as gearing im runnig a stock set up 14 front 47 rear.
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Gas pouring out of the overflow means the floats are stuck. sometimes can be out of adjustment which affects performance, big time. Pouring waaay too much fuel in at idle would make it puke, till you finally got it wound out. Its just a little tab that closes off the pin. A visual inspection usually shows the cause. Sometimes a couple taps on it fix it, if you're lucky. I mentioned the overflows tubes, because if they get clogged then, when flooding because floats are stuck it wouldn't be able to get out. Thats bad. You can fill up bottom with liquid fuel and lock it up that way, in worse case scenario. If you see liquids pouring out, its usually worth checking out. Its not normal on a kx500. That sounds like that might be it!!!
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Hey Khaavet
I'm having the same problem!
I can't get the tire up in 2,3,4 gear and seems sluggish at low speeds.
A friend of mine has a 2004 crf250(stock) and he keeps up with me!!! That's Not right
Its a 92kx500 fmf pipe with 168 main and 60 pilot.
I did a compression test and its at 150psi.
I have been fouling plugs at low speeds in trails, its carbon fouled.
I'm looking to jet the carb not sure which way to go, i'm going to order reed spacers next week.
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Read spacers make it slower. Start by cleaning carb and air cleaner. Lean out the carb until its tan. Run bike at top end and shut off right away the check. At 2500 ft mine was at 162 and a 58 or maybe even a 55. Make sure the correct needle is installed and recheck those valves. Check compression with throttle wide open to let in air. Make sure that is even the correct carb should be a pwk 39 on a stock machine. It sounds like it ran good at first untill it warmed up. I had that problem once and noticed that better fuel made a big difference. Good luck.