KX Riders
Maintenance & Technical => KX500 Original => Topic started by: BlackHills on January 27, 2008, 05:30:47 AM
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I am tearing down the top end on my 2001 kx 500 for the first time. I have owned the bike for 2 years. I know that I should be doing this more often anyway, but the bike was running so great I didn't want to screw it up.
Anyway my bike has enough broken parts and the cold starting was getting so bad that I knew it was about time. I tore the bike apart yesterday and found a few things that need to be fixed: aftermarket reed valves cracked, broken support on radiator, etc. I new from the previous owner that the cylinder had been sleaved so I expected that, but I didn't expect the amount of metal removal that was done on the intake ports.
I found a couple of small cracks in the "normal" locations on the intake ports, but they don't appear to be cracked all the way through. My problem is that I really can't afford to put more money into this bike so I wanted opinions on the pictures I took and what you think should/can be done.
Cylinder Walls:
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2721.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2722.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2737.jpg)
Intake Ports:
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2724.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2727.jpg)
Piston:
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2733.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2734.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2736.jpg)
Also, I am having serious problems removing the allen bolt that holds the KIPS in place. I am using so much force that I figure I am going to either break the allen wrench or strip the bolt. Anyone have any advice?
Their is also an issue with the amount of crap in the exhaust ports. Is this normal?
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2730.jpg)
(http://i271.photobucket.com/albums/jj149/BlackHillsKX/IMG_2731.jpg)
I can take more pictures of different areas, and of more detail if needed. I just want to make sure I get this back running and it doesn't self destruct on me in a month.
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the cracks i see are from running a sleave in a cylinder not meant for a sleeve .. change to belray h1r oil at 50.to1 to clean up exhast port and be sure to use a wiesco forged piston to prevent future problems
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I ran a sleeved cylinder with all the same cracks that yours has for eight or nine years with out problem one. I always imagined the top of the cylinder blowing off the bottom but it never happend unfortutunately, that would have been one cool blow up. :evil: :lol: :lol:
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has long you don't have this problem your ok.
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Thanks guys. I don't think the cracks are that bad so I am hoping to put it back together the way it is. I have a Wiseco top end kit that should be here in a couple of days (with piston).
Now a couple of follow-up questions. How do I clean up the inside of the cylinder? Not the cylinder walls themselves, but all the ports and areas with all the buildup. Also what is the best way to clean up bolts and nuts that need a little TLC?
So far I have been cleaning up the outside of the engine with oven cleaner to get rid of the gunk (I had a big crack in my exhaust and a bunch of spooge all over my engine as a result). For the bolts I was planning on soaking them in gas, diesel or kerosene then cleaning them with a wire brush or an attachment on a dremel. I would like to get my bike looking somewhat presentable and serviceable again instead of just the hillclimbing beast that it is :-D.
Anyone have any special tips or advice on cleaning up all the ports on the cylinder and bolts?
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hey blackhills, i have a friend that cleaned the inside of his ktm550 mxc pipe by chucking up an old piece of speedo cable in his drill. he frayed the end out and put a 90 degree bend on the end and went to town on the pipe. i couldn't believe how muck soot he got out of it. the same method may work for you on those "hard to get to" places on the exhaust ports. MADDOGGY
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go to the car piant store for car body shops... buy 5 gallon can of piant thinner,,, let cylinder soak in it over night till comes out like new ps ithink there are cheap piant thinners that dont work as good and you can ussally blow carbon off with compreesd air when you get done soaking cylinder
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Thanks for the tips.
I finally did get the allen bolt (on the KIPS assembly) to break free, I had to put the cylinder back on the bike so I could get more leverage. After pulling out all the parts I have officially decided to run good quality 2 stroke oil at a higher ratio. Those things are just COVERED in carbon build up. I am pretty amazed the bike still ran as good as it did. I have been using whatever cheap oil I can find and mixing it at 32:1, so I am going to use some quality oil at 50:1 from now on.
Luckily or unfortunately I won't have to remove carbon from my exhaust since I am sending it to the piperepair.com guys to fix an incident I had with a rock while climbing.
I think I will try the paint thinner method to remove all the carbon. It seems pretty simple and will get all the hard to reach spots.
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has long you don't have this problem your ok.
OR like this! :-D
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I use Permatex spray gasket remover. Comes right off. Two cans will be enough, make sure you use nitril gloves.
(http://i114.photobucket.com/albums/n248/Jeekinz/KXPics004.jpg)
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/KXPics1002.jpg)
Ball hone the cylinder
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/KXPics1001.jpg)
Polished exhaust port
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/KXPics2004.jpg)
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/assembly1004.jpg)
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That cylinder looks like the plating is worn threw by the rings at top :?
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That cylinder looks like the plating is worn threw by the rings at top :?
Nope, just the reflection. When you measure a cylinder you should measure inside the ring groove too.
The groove in that cylinder looks worse than it is. I should get 2-3 more rebuilds on it before it will need attention. That cylinder was only out of round 0.001 from top to bottom.
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Hi everyone Correct me if I'm wrong about a top end rebuild. Its been my understanding that any cylinder that has been chromed, nikasil, plated ect.. is not to be honed? Is this correct?
Serafin
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It should be honed but do it quickly as not to eat through the plating.
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Well I just had a issue with my rebuild. I got my Wiseco top end kit today, and the cylinder is smaller than the one that I took out (by about 1/16th). I guess someone before me decided to bore it out to something bigger than a 500cc???
This is where things get over my head and beyond the tools that I own. I think I will take it to a local machine shop (after its cleaned) and have them hone it and give me an accurate measurement for the piston. I guess I will have to send my top end kit back and try again....
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i would not hone it with anything but the brush set up that wiesco sells for plated cylinders
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I liberally spray WD-40 in the cylinder then use a Snap-On ball hone in a cordless drill on high speed. Move the drill up and down pretty fast to create about a 30-35 degree cross hatch. Only hone for 10-15 seconds to remove any glazing, scoring or metal transfer. Been doing it for years, never a problem.
BTW - that was a basket case engine I rebuilt. Here's the details. http://www.thumpertalk.com/forum/showthread.php?t=594486 (http://www.thumpertalk.com/forum/showthread.php?t=594486)
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What's your piston to cylinder clearance? looking at the third picture It looks excessive. Are you sure the plating is not worn threw that aluminum colored spot shows up in all your pictures :|
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What's your piston to cylinder clearance? looking at the third picture It looks excessive. Are you sure the plating is not worn threw that aluminum colored spot shows up in all your pistures :|
lol - no dude. This wasn't my first engine rebuild. lol
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LOL-Ok it just looks funny in the picture I guess. I have rebuilt one or two motors myself. LOL
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Im doing a topend rebuild also, but o cant figure out if i got an twisted actuator out off the kips assembly like the one in the pic. Does any one have a pic on where it belongs ?
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/KXPics1002.jpg)
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That pic was only to show how good the gasket remover works on decarbonizing. That's a 250 KIPS.
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i would not hone it with anything but the brush set up that wiesco sells for plated cylinders
Hey Stewart why wouldn't you use a ball hone?
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its been my opion that the size or diameter of the bore and proper piston clearance is not achived by using a ball hone and if those sizes are right bore dia . striaght ness .etc..... the cylinder that his been plated makes better power the more its been run and and deglassing it did not improve the power on a plated cylinder
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Im doing a topend rebuild also, but o cant figure out if i got an twisted actuator out off the kips assembly like the one in the pic. Does any one have a pic on where it belongs ?
(http://i114.photobucket.com/albums/n248/Jeekinz/KX%20Project/KXPics1002.jpg)
i've got the same question about the twisted piece? w.t.h.d.t.c.f "where the heck did that come from"? i could of sworn i followed my service manual instructions.
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its been my opion that the size or diameter of the bore and proper piston clearance is not achived by using a ball hone and if those sizes are right bore dia . striaght ness .etc..... the cylinder that his been plated makes better power the more its been run and and deglassing it did not improve the power on a plated cylinder
stewart i thought the ball hone was used to make the cross hack in the cylinder which makes for even oil flow throughout the cylinder. i'm not sure about the performance aspect. the ball hone takes nothing away from the cylinder just creates peaks and valleys. ok takes a little (mi-nute amount).
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BTW: This only pertains to the KX250 NOT 500! Didn't intend to hi-jack the thread. :wink:
The piece that looks like a twisted gear is the Main Valve Rod. Look on the front of your cylinder for a little cap that looks like a number '8', it has a phillips screw holding it in. The end of the rod has a notch cut in it, that notch will be toward the front of the engine when installed.
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its been my opion that the size or diameter of the bore and proper piston clearance is not achived by using a ball hone and if those sizes are right bore dia . striaght ness .etc..... the cylinder that his been plated makes better power the more its been run and and deglassing it did not improve the power on a plated cylinder
I don't use the hone to adjust the cylinder size in any way. I like to have a clean surface for the new rings to seat to without any wear from the previous piston. Just like sanding down a shaft when you install a new seal.
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i think honeing to a size for proper clearnce and cross hatch is essentiol for 2 or four stroke...i think deglazing the bore on a nonplated cylinder is fine 2 or 4 stroke they look nice ... but on a plated 2 stroke bore i found more power in the cylinder the longer i ran it with just changing pistons and rings no deglazing the where the bore size was right on size ....wiesco siad they sold a diamond whip type brush for 2 stroke deglaze .. but were not to big on ballbrushing ..i belive the plating laps to a better seal after more run time ...ps i used to work directly with sunnen hone company on new engine cylinder manufacture for cessnea aircraft and was a counsltant for some major rebuilders on honing
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stewart now i don't know what i want to do on my cylinder! yicks i'ma cornfused :| :| :|.
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dont worrey about the eye wash ...its easy to fall for that..
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The primary reason I was told (by a wiesco rep) not to use a ball hone, when it is spun in the cylinder bore, it drops into the ports and as the balls come out they snap against the cylinder wall and can cause pitting where the ball mnakes contact with the wall. NEVER spin a ball hone fast, that will create havoc on your cylinder. If you must feel that you need to deglaze, use the brush hones Wiesco offers, and only make a token pass
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I'd like to try one of those brushed you talk about and compare it to a ball hone. I've had the same ball hone set (125's & 250's) for years from Snap-on. I think the "ball snap" you speak of is probobly over thinking the situation. Even if it did occur, it would be on a microscopic level. And I can't see how that would affect a 2 stroke engine.
Anyway, the ball hone process only takes 10 seconds. It's not like your siting there for 45 minutes spinning the thing.
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here's the wiseco link for the bruch hone.
http://www.wiseco.com/PDFs/Catalogs/CB07/Comp-ComprsrSleevesHoneBrushes.pdf
The point is it can make a chip in the plating, this wil give a foot hold to start damaging the cylinder plating. Obviously your going to do what you think is best, and I'm going to do the same, for me, I don't use a ball hone, either, nothing, a brush hone or a rigid hone in that order.
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Yes, I read that, thanks. I wonder what RPM range they recommend? Like I said, I'd like to try one on the next rebuild. I mean, let's face it, this is what they do. I know what I'm taught.
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I have never honed a plated cylinder myself. any time I have ever honed an iron cylinder it has been in and out once or twice that's it, just enough to put a 45 degree cross hatch on it. From my experience a ceramic plated cylinder that's worth using still has a cross hatch in it. Any time a plated cylinder shows wear of any kind I would elect to have it replated and let Maxpower put a nice cross hatch on it for me. I could not sleep at night knowing I put a brand new shiney piston in a worn out hole. That's just me I'm anal like that. :wink:
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I have never honed a plated cylinder myself. any time I have ever honed an iron cylinder it has been in and out once or twice that's it, just enough to put a 45 degree cross hatch on it. From my experience a ceramic plated cylinder that's worth using still has a cross hatch in it. Any time a plated cylinder shows wear of any kind I would elect to have it replated and let Maxpower put a nice cross hatch on it for me. I could not sleep at night knowing I put a brand new shiney piston in a worn out hole. That's just me I'm anal like that. :wink:
dittoooooooooooooooooooooooooooooooooo stewart
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I'm glad I'm good company on this one. I don't mess with saving money on do-it-yourself rebuilds. Its risky business putting a new piston in a cylinder that is not replated. If a motor has low hours and no damage, you can surely put a piston in it, but only once like that. If there's damage of any kind, it is thru the plating. They clean up the cylinder and plating fills in tolerances back to stock size. Any boring or honing should be done by experienced engine builder with mic's. If you want to save money and do most of the work, dissassemble, take just cylinder to engine builder. Order your rebuild kit after varifying piston size, and reassemble yourself. Plating and micing are only a fraction of the costs and labors of the total rebuild. They like to get a mark-up on the rebuild kit, and rightfully so, if you are not confident enough to get the parts yourself. You will save money in the long run, delegating out some things not to mention the added peace of mind while ripping it up out in the wilds.....