Un-Burnt fuel leaking out

[kiwikx500]

Have oil coming out the end of the small black plastic elbow of underside of power valve (kickstart side) plus its coming out where exhausts meets motor.

- Bike was also putting out white smoke
- Added 170 mls of oil for 7 litres of fuel (40 to 1)
- Bike runs well in top gear wound out but power does not seem smooth else where
- New coil has been fitted and new plug (bike starts well)

- Any ideas please what could be causing this ?

[BrokenSpoke]

Crank seal leaking oil into the motor

[kiwikx500]

Cheers BrokenSpoke for info - Is it an expensive fix ? Will look on here for a diagram to try and see what you exactly mean.

[kiwikx500]

With ya now, The last run i did I added some fuel that had been sitting for months in the bike tank (4 months damp garage) and ended up stalling it or it died (when I came to a stop) and noticed water in the oil mixture coming out the black elbow - checked radiator and there was a slight drop in water - so do not know now if it was water from the fuel or something worse.

Bike would not start again, itching to drain fuel and add new - but will have to wait for right knee to come right after all the kicking and the 8 km walk back to the van

[Polar-Bus]

Have oil coming out the end of the small black plastic elbow of underside of power valve (kickstart side) plus its coming out where exhausts meets motor.

- Bike was also putting out white smoke
- Added 170 mls of oil for 7 litres of fuel (40 to 1)
- Bike runs well in top gear wound out but power does not seem smooth else where
- New coil has been fitted and new plug (bike starts well)

- Any ideas please what could be causing this ?

If your running 32:1 fuel mix ratio with the stock KX500 jetting in warmer temps, this is why you have the imfamous "spooge" oil coming out everywhere. Low to midrange jetting on the KX500 is critical to good running. The KX500's come jetted way rich for use with the 32:1 ratio. I premix at 42:1, using Klotz R50 full synthetic, with a  162 main, needle leaned out 1 clip position from stock, and 1 size leaner pilot jet in the summer. I also run full race gas, so I can run a leaner main jet than someone that uses pump gas.

[FuriouSly]

What up Kiwi..
   The oil at the powervalve elbow is probably the oil seal for the pv arm which is on the clutch cover and usually just popped out of its seat, just push it back in or replace it.  It can be replaced without removing the side case, it just presses in from the outside.  It could also be the seal on the pv rack linkage that comes out of the cylinder but not likely.

   The gunk at the pipe/cylinder connection is typical for the KX5.  Running crappy premix, too thick a mix (32:1, 28:1...etc), too rich on the jetting, or old fuel mix (basically acts like a thicker mix because fuel losses its potency over time).  There are two o-rings on the pipe which help seal the connection at the cylinder and these wear out very fast (10 hrs of use).  Also on the stock pipe there is a brass compression ring that fits in the connection as well which helps with the seal and vibrations.

   The white smoke is water in the combustion chamber.  You probably already identified the source (water in fuel).  Otherwise you would have to have a crack in the cylinder water jackets and this not that common.

Peace.... Sly

[BrokenSpoke]

Crank seal leaking oil into the motor

Apologies, my mistake. White smoke is water in the fuel, not oil blowing past the crank seal.  Oil leaking in through the crank seal would be blue smoke.     

[c-152]

I had a 92 RMX250 that taught me (the hard way of course) not to premix @ 32:1.  Every few months it would be harder and hard to start. then it started running really bad especially in the tight stuff.  It became hard to start and would not stay running.  I changed the jetting and moved the needle but it was useless.  It was not until I tor it down and noticed that my pwoervalve was full (I mean full) of gunk.  The pipe also had a lot of gunk.  I cleaned it all out, put it back together, went back to the stock jetting and started running 42:1.  The bike ran great after that.  I am just glad to have learned that lesson on the 250 as opposed to kicking the 500 as many time as I did that 250.  Unlike most people on this forum, I have not had jetting issues (I am knocking on wood right now).  I believe if you clean up the powervalve and run a good synthetic oil @ 42:1 you should be okay

[kiwikx500]

Cheers team for all your thoughts 

I did use cheaper premix oil than normal so fits with what Sly was saying the reason it is coming out of the exhaust port.
The brass ring and O rings are around 12 hrs of running old.

(10 hrs only for the O rings - no wonder the dirty 5 had none when i got it.)

Oil still comes out of elbow with synthetic oil so will look at all suggestions.

The guy I bought it off said he replaced the needle with a number 7 (pretty sure that was the size - will look around on computer history to confirm soon)

Have mixture screw set at 1 1/4 turns out

Big mystery now is where is all the gearbox oil been going that i have been feeding the gearbox - use to think when I was greener than I am now that the oil coming from the elbow was gearbox oil as it always seemed to drop.

Have read before the gearbox oil eye level glass is tricky on the KX - but even after having bike upright for 5 mins still looks like it needs more oil - must have put in a few litres over 20 hrs of use.

Can anyone tell me please how much oil the gearbox takes from bone dry to bring the oil level up to half way on the eye level glass ? Is the gearbox meant to consume oil ?

[Polar-Bus]

Big mystery now is where is all the gearbox oil been going that i have been feeding the gearbox - use to think when I was greener than I am now that the oil coming from the elbow was gearbox oil as it always seemed to drop.

Have read before the gearbox oil eye level glass is tricky on the KX - but even after having bike upright for 5 mins still looks like it needs more oil - must have put in a few litres over 20 hrs of use.

Can anyone tell me please how much oil the gearbox takes from bone dry to bring the oil level up to half way on the eye level glass ? Is the gearbox meant to consume oil ?

OK, now I about guarantee you have a blown primary gear crank seal, which will allow transmission oil to be sucked into the crankcase and mixed/burned with your fuel. This explains the extra raw oil everywhere, and your diminishing trans fluid levels. Problem is I believe the cases have to be split to replace that seal...

[blackkx]

 It sounds to me like you have crank seal leak , if your having to add oil to it and its not leaking out then only one other place would be combustion chamber . I would do a thourogh inspection of the oil drain plug area and the case gaskets to make sure its not leaking it out before looking any further . Havent had any badluck with crankseals myself but i have heard they are common problems in the big bore kawi's . good luck

[kiwikx500]

Cheerz - sounds like Broken spoke was onto it earlier as well.

Is there a figure please for gearbox oil capacity ? (curious)

Anyone else in here had this common crank seal problem - just not keen on replacing the seal for it to go again.

[Danger4u2]

800cc or 27.1 ounces    1983-on

[kiwikx500]

Howdy Danger - Thank you for that - is that 800 mls - (metric here in kiwi land)

[kiwikx500]

Found conversion table - see that its 0.8 of a liter - thanks

Looks like a crank seal than alright  xr 250 an attactive looking bike at the mo loloolloll