New Owner

[95formula847]

Hey whats up guys this is my first post. Im now the proud owner of a 1991 KX500 that i got for $800. Its in pretty good shape for how old it is. Ive been riding my whole life but never anything this big. In the past i have had a KX125 and RM250. I currently have a ZX12R street bike.

Anyways i have a few questions about the bike. First off its pretty hard to start. And not because its physically difficult. It just doesnt want to start and idle.i have to rev it to keep it running. The bike sat for a few months so im sure it needs the carb gone through and i might as well have the jetting checked. Sound about right? Also when i get it runnin its pretty sluggish and rough in first gear and doesnt really go anywhere. If i crack the throttle and go through the gears it will eventually pick up around 4th gear but still doesnt feel near as powerful as it should. Given i ride a ZX12 on a regular basis but it still doesnt feel right. Im attributing all this with it sitting for months and needing the carb gone through? If theres a starting method you guys use that works for when i get it running right id like to know it.

Next problem it has is the front sprocket is slinging small amounts of grease. Is there a seal in there or is it somethin else? Its not slingin alot just a small amount but still... its a leak.

Third problem it has is that the rear shock is extremely soft. I weigh 200 lbs and i can just sit on it and it sinks a good bit and if i bounce ever so slightly it drops a whole bunch more. Looks like a low rider lol. Are the rear shocks rebuildable? If so is this most likely the problem... just needs a rebuild?

Last but not least the head pipe leaks where it meets the engine. When i start the bike up it puffs smoke out and has alittle oil residue. The previous owner says its been cracked in other places a few times and fixed. Its the stock pipe and has two springs holding it on. Any ideas on this? Will putting a gnarly pipe on fix the problem most likely or can the mating surface on the engine be the problem?

Oh and the front brake disc wiggles on the circular metal pieces between it and the center pice of the disc. Is this normal?

The bike is gonna be used for trail riding so id like to gear it accordingly. Ive also read a gnarly pipe is good for low end but what about a silencer to pair it with? It has a really beat up pro circuit one on it now. Im going to change the plug, drain the gas and put turbo blue race gas in it after the shop goes through the carb. Any suggestions on what plug to run? What ratio do you guys mix your fuel/oil?

Im sorry i asked alot of questions but i figured one big thread would be better than numerous small threads. Thanks alot.

[kxpegger]

Hey whats up guys this is my first post. Im now the proud owner of a 1991 KX500 that i got for $800. Its in pretty good shape for how old it is. Ive been riding my whole life but never anything this big. In the past i have had a KX125 and RM250. I currently have a ZX12R street bike.

Anyways i have a few questions about the bike. First off its pretty hard to start. And not because its physically difficult. It just doesnt want to start and idle.i have to rev it to keep it running. The bike sat for a few months so im sure it needs the carb gone through and i might as well have the jetting checked. Sound about right? Also when i get it runnin its pretty sluggish and rough in first gear and doesnt really go anywhere. If i crack the throttle and go through the gears it will eventually pick up around 4th gear but still doesnt feel near as powerful as it should. Given i ride a ZX12 on a regular basis but it still doesnt feel right. Im attributing all this with it sitting for months and needing the carb gone through? If theres a starting method you guys use that works for when i get it running right id like to know it.

Next problem it has is the front sprocket is slinging small amounts of grease. Is there a seal in there or is it somethin else? Its not slingin alot just a small amount but still... its a leak.

Third problem it has is that the rear shock is extremely soft. I weigh 200 lbs and i can just sit on it and it sinks a good bit and if i bounce ever so slightly it drops a whole bunch more. Looks like a low rider lol. Are the rear shocks rebuildable? If so is this most likely the problem... just needs a rebuild?

Last but not least the head pipe leaks where it meets the engine. When i start the bike up it puffs smoke out and has alittle oil residue. The previous owner says its been cracked in other places a few times and fixed. Its the stock pipe and has two springs holding it on. Any ideas on this? Will putting a gnarly pipe on fix the problem most likely or can the mating surface on the engine be the problem?

Oh and the front brake disc wiggles on the circular metal pieces between it and the center pice of the disc. Is this normal?

The bike is gonna be used for trail riding so id like to gear it accordingly. Ive also read a gnarly pipe is good for low end but what about a silencer to pair it with? It has a really beat up pro circuit one on it now. Im going to change the plug, drain the gas and put turbo blue race gas in it after the shop goes through the carb. Any suggestions on what plug to run? What ratio do you guys mix your fuel/oil?

Im sorry i asked alot of questions but i figured one big thread would be better than numerous small threads. Thanks alot.

Don't know where your at but I'm using a N82M needle, 55 pilot and a 168 main. About 1 1/2 turns out on the air screw. If your idle is set to low this will also make it hard to start especially when the engine is warm.

Sounds like a bad seal and/or spacer.

Check the nitrogen precharge. Also your year bike can also use air according to the manual but nitrogen is preferred.

Mine leaks too after about 6 to 8 rides! Change crush washer, new "O" rings and use some high temp RTV to get a few extra rides out of it.

If your front brake rotor is full floating some play is normal. If you can make it click by hand front and rear and side to side it may be worn. It's a judgement call but if you don't like what your feeling when applying the brake change the rotor.

Depends on the type of oil but I think most run about 40:1.

[jdcowboy]

Welcome....for starters I run Amsoil 100:1 in all my stuff.  I usually mix it at 50 to 1 and have had no problems.   If you bike has been sitting a while I would start by draining the fuel tank and carburater.  There is a bolt in the bottum of the float bowl to empty the carb.  Start with that.  Should not need any special starting proceedures.  3 or 4 kicks and you should be running.
Good luck...
Tex

[oic0]

When I first got mine the guy had the idle set very low and the idle mix set very lean. Setting the carb so it will idle and adjusting the idle mix made mine much easier to start. After doing that the next time I went outside and tried to start it, it scared the crap out of me when it sprung to life on the second kick! I was used to sweating and being half worn out before getting it to start.

Also, is the plug fouled?

[95formula847]

The plug could very well be fouled. I havent pulled it yet. Im gonna take it today to a local shop to get the carb cleaned, jetting checked and have them do a once over. Ill decide what to fix now but i wanna start with getting it running. Then get the shock rebuilt cause the sag is rediculous.

[95formula847]

today i put a new plug in it. The old plug was very clean and was tan in color. I also drained the gas and put fresh turbo blue mixed 50 to 1. I rode it around and same thing. Doesnt feel much different. It still wont go more than maybe 10 mph in first before it sounds like its dieing. It fells tourquey down low but has no grunt through the middle or up top at all.

[95formula847]

im tryin to find out how to check the kips but cant find anything about it. is this another term for the power valve? could this be causing problems? it runs like it has the choke on. thats the best description.

[oic0]

How is the pipe? is it majorly crushed or full of crap? maybe some dirt dobbers living in the tail pipe? My powervalve is sort of screwed up. It just sort of flops around. Bike still runs like a raped ape though. You can test yours though by removing the exhaust pipe and manually actuating the little control arm under the plastic cover on the side of the engine to see if it opens and closes. Can also leave that cover off with the bike running (pipe on of course) and see if revving moves the arm like it should.

Did you remove the main jet and make sure it is clean? Also see if its main jet and needle position conform atleast somewhat to http://www.kxriders.com/forums/index.php?page=11


I'm in the same boat as you though. I bought a bit of a basket case and have been going through it. I need to fix my powervalve, put in a new piston, replace several spokes, fork seals, etc... Big pain when you want to play with your new toy huh?

[95formula847]

The headpipe has been cracked and fixed many times, its also got a few medium dents on it and leaks at the engine flange. I took off the left grey plastic cover that has 5-6 bolts and all there was in there was a large gerey cylinder that spun? crank weight? I would really love to find a pic of what cover to take off because i have been searching for days and im completely confused at what im looking for.

I did not remove the main jet. I havnt done anything to the carb yet. Which screw is the idle screw? There is a screw with a spring and a small gold screw almost flush below that. Which is which?

And yea i want to ride so bad its not even funny. When i use to ride a few years ago on a regular basis all of my buddies thought it was boring and never wanted to get bikes/quads. Now after i have sold all my off road toys... literally 10 of my freinds got bikes and ride every weekend.

UPDATE: i took off the silencer cause it was leaking horribly where it meets the head pipe. WOW! The rivets holding the center section are all gone and its now held with one huge drywall screw. I pulled the 3 bolts out of the end of the silencer and pulled the center section out. I found the packing to be soaked with old oil and almost burnt the whole way through. It was comming apart in flakes and chunks. I rode the bike around for about a minute with no silencer and man what a difference. Bike has alot more power. So im gonna get a new silencer and a gnarly pipe. What brand silencer should i go with for trail riding to pair up with the gnarly pipe?

[DoldGuy]

95formula,
I have a FMF Gnarly that I probably will not be using if you are interested. Depending on which Coast you are closest to, I believe Motorad has one too (I am East Coast, he's West). As far as silencers, I think you would be happy with the FMF or PC

[95formula847]

Thanks alot pal. Ill prob be buyin brand new. If you send me pics ill def check it out and if it doesnt leak and isnt dented i might just grab it up. I live in maryland btw. Which fmf pipe should i get for trails? I have found good prices on the power core and turbine core. I like the look of the power core and the price.

[95formula847]

Ok guys. I got a new sprocket o-ring and collar, a clymer maintenance manual, FMF Power Core silencer and UNI multistage filter. I took the reeds out and they look new. What should they look like? Also do i take the left hand side cover off that says kawasaki on it to check the power valve? what am i looking for? when i took it off today all i saw was a large cylinder that spun. Im very mechanically inclined as im an aircraft tech i just dont try to assume with 2 stroke engines.

Also i took a look at the rear shock. There is a bottle on the right hand top side of the shock. On the bottom of this bottle it has an air fitting. Can i just try to at nitrogen at my shop and see if that helps with the crazy sag im getting? Also i took a screwdriver and pushed on the needle in the fitting and nothing came out at all. Would this mean its empty? I dont know how this system works.

[DoldGuy]

95Formula,

The cover you removed is the Stator Cover (Ignition/Generator) , the one you are looking for is on the lower right side of the cylinder (just above the water pump) it is a small plastic cover with only 2 bolts holding it in place. If you hold the Reeds up to a light, look into the Reed Cage to see if the reeds are "Lifted" off of the block itself, if so, you need new reeds. The "Bottle" on your shock is the Nitrogen Bladder Chamber, and yes it should have Nitrogen in there. If there is none, that will cause the Low Rider Effect, and for Just Testing Purposes, Put some air in the bladder (Approx 100 lbs) to see if this helps cure the effect, and if so rebuild the shock and install Nitrogen.
I am just South of the Potomac River (VA) and will send more photos if needed of the Pipe

[oic0]

Might help you figure the bike out just a bit.
http://shop.thumpertalk.com/oem.asp?partcategory=381737&manufacturer=4&category=3&year=1991&model=8826

[95formula847]

Ok thanks alot. Ill look tonight after work for the other cover. Ill also look at the reeds and mabye post pics. And also there is nothing in the nitrogen bladder. Your not too far from me then which is good. On another note. I took the carb apart. Wasnt near as hard as i thought. i got the bowl off and found two jets. The pilot jet is a 52 while the main is a 172. Where is the needle jet number located? I know where the needle jet is but i cant seem to find a number. Also what is the gold screw for on the side of the carb below the air screw? Where should i set my air screw and this gold screw as a baseline?

95Formula,

The cover you removed is the Stator Cover (Ignition/Generator) , the one you are looking for is on the lower right side of the cylinder (just above the water pump) it is a small plastic cover with only 2 bolts holding it in place. If you hold the Reeds up to a light, look into the Reed Cage to see if the reeds are "Lifted" off of the block itself, if so, you need new reeds. The "Bottle" on your shock is the Nitrogen Bladder Chamber, and yes it should have Nitrogen in there. If there is none, that will cause the Low Rider Effect, and for Just Testing Purposes, Put some air in the bladder (Approx 100 lbs) to see if this helps cure the effect, and if so rebuild the shock and install Nitrogen.
I am just South of the Potomac River (VA) and will send more photos if needed of the Pipe