Need Help W 02' Kx500

[hawaiirider]

my current ride and pride and joy is this bike and its been ultra reliable for years now but is starting to show age. the piston and rings are 10 rides old, the cylinder is original and has mega compression(by foot). carbs clean, great spark. The problem is it has started to surge down low, as in a irratic idle? this makes me think its lean but everything checks out? the main problem is now the bike is starting to constantly overheat in the ultratight trails out here, didnt before. any suggestions? pilot jet is clean, should i raise the needle? top end absolutley screams but the plug is brown black not white. never did any mods to jetting either?

[fabiodriven]

If you're getting that lean condition and your jets are all checking out OK and there isn't any leaks around the carb, it may be time for a set of crank seals. Sometimes you can get away with doing just the left one. That is usually the culprit because that seal is a "dry" seal. The seal on the right is usually not to blame because the transmission oil tends to keep it alive longer. The proper way to do it would be to tear into it, check out the top end, and get the crank bearings and seals replaced.

[hawaiirider]

fabiodriven, would a compression guage show if this was true? sounds like it could be the prob no air leaks at all i checked with a can of starter fluid

[JohnR.]

Shouldn't this be in the bikersville (http://www.3wheelerworldforums.com/forumdisplay.php?f=12) forum?

[hawaiirider]

i dont know man, i didnt even notice it until yall pointed it out!! besides this motor bike might turn into a trike one day!

[fabiodriven]

Shouldn't this be in the bikersville (http://www.3wheelerworldforums.com/forumdisplay.php?f=12) forum?

I don't have any problems with this being in trikesylvania because alot of guys on here have trikes with KX 500 engines in them.

Hawaii, I'm not sure if a compression tester would help you or not. If there's a way to check crank seals with a compression tester, I don't know about it. You gotta figure, if the machine is 10 years old it could probably use a set of crank seals.

[3Razors]

Take the stator cover off the side of the engine. If you see any oil/gas buildup in there then yes crank seal could be bad. I would double check every other item twice and make sure before changing crank seals, its a BIG job.

Have a look at the powervalves as they could become gunked up after a few years and aren't opening and closing properly. Is this bike completely stock, even the jetting?

Has the radiator coolant been changed on a regular basis? If not you may have corrosion buildup in the radiator passages.

[hawaiirider]

thanks for all the help, its got a procircuit exhaust and vforce reed valve but has been pro-jetted and had no trouble for yrs. until now. ill check the cover. im sure that the rubber seal to the powervalve is leaking oil a little, didnt know this could do anything? its been like that a while now.

[300rman]

well, the topend only being 10 rides old, that wouldnt be the culprit.

when its sitting there running, spray starting fluid around the carb/intake boot (NOT into the carb itself)

if the running speed changes at all, you have an external air leak, hence the lean condition.

if that checks out OK, then it is probably the crank seals.

[3Razors]

well, the topend only being 10 rides old, that wouldnt be the culprit.

when its sitting there running, spray starting fluid around the carb/intake boot (NOT into the carb itself)

if the running speed changes at all, you have an external air leak, hence the lean condition.

if that checks out OK, then it is probably the crank seals.

Just because it has a new piston/rings does not mean the powervalve is not gunked up and in perfect working order. KX500 has Nikasil plating so a person could have just threw in a new piston and assembled without checking/cleaning the valves. I myself highly doubt it's crankseals on a 02 motor. Also if it is just a minor surge on the bottom end I've heard of numerous KX5's like that as it is considered normal and the jetting is close. Follow the team green jetting chart and see if it cleans things up a bit.

http://www.teamgreennews.ca/pdf/2004_jetting_chart.pdf

[hawaiirider]

thanks i checked w starting fluid, its good no leaks at all. i did not change the jetting or any mods from before it just started ba bing ba bing up till a 1/4 throttle one day? this also makes it overheat and scream on top-must be lean! im guessing its the crank or powervalve. how do i check and clean the powervalve? its the first bike ive owned with one.

[MTS]

to do it right, the cylinder comes off, you have to dismantle all the linkages pull the valve out, bead blast everything, the kx's are a little trickier too becuse of the aux ex ports, have to time them,

[tecat-z]

Do a leakdown test...... That will determine condition of dry side crank seal.

[hawaiirider]

pulled the ignition cover off, she looks clean. the rubber peice form clutch cover to jug for the valve looks bad and is leaking a little, could this be the culprit?

[3Razors]

That rubber piece is really just a dust/water cover for the powervalve arm, and is not the culprit. The valves are inside the cylinder.

[hawaiirider]

thanks for the help on this thread and yes 3razors 4strokes areNOT the way of the future!!!!!!!!!!!!!