Author Topic: Black gunk  (Read 2931 times)

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Offline cattamer

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Black gunk
« on: May 03, 2009, 12:55:28 AM »
I have a '92 500,when I bought it I noticed it had alot of black oil residue on front of motor and exhaust, and had even blown out on side panel and swingarm.The guy I bought it from didn't know much about bikes'and so I thought oil/gas mixture to rich.I owned a '90 and it never did this.This one has a stealy flywheel weight,and Knarly pipe, but doesn't have the bottom end that my other had.It doesn,t foul plugs,and starts easily.It seems to want to jump off bottom end more than the '90.Is this caused by KIPS,or something else.Still love my big-bore gas gusler,climbed hill yesterday while 4-bangers watched! :?

Offline martinfan30

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Re: Black gunk
« Reply #1 on: May 03, 2009, 07:15:03 AM »
If you have black splooge coming out at the head pipe, your jetting is off. The jetting is keeping the cylinder temps from getting hot enough to burn off the oil in the premix.
2000 KX500
2005 XR650L

Neither are stock, and both are great desert bikes.

Offline atrain40

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Re: Black gunk
« Reply #2 on: May 03, 2009, 09:52:36 AM »
i have a 1991 that i just bought and i mix the gas at 32:1 but am gonna change it to 40:1 or 44:1 because of so much splooge coming from exhaust port on front of motor. and bike runs great. it has procircuit exhaust front and back and he said the jetting is set up the way procircuit has it. i live in bakersfield CA and mainly ride in the dez and sometimes mountains jetting help please.

Offline cattamer

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Re: Black gunk
« Reply #3 on: May 03, 2009, 10:43:29 AM »
Thanks,Martinfan30,I will pick up a kit and try some different settings.I am in SC and probably about 8 or 9 hundred feet above sea level,do you know what needle setting to run or do I just need to experiment?

Offline cbxracer30

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Re: Black gunk
« Reply #4 on: May 03, 2009, 01:16:53 PM »
I've seen this alot on bikes that I bought used with the former owner running cheap 2stroke oil at 32 to 1 . The first thing I would do is take the pipe and silencer off and clean them out , change the silencer packing and rejet for 50 to 1 . For trail riding I like running Belray SI-7 its smokeless and for racing I'm gonna start running Motorex 2T racing if its good for the big teams oh yea and Roostdaddy its good enough for me. CBX
Yep, you can ride it - if YOU can start it !!

Offline cattamer

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Re: Black gunk
« Reply #5 on: May 04, 2009, 01:00:41 PM »
Thanks CBX,any suggestions on what is best to clean out pipe?.I have an aftermarket silencer on way. :-D

Offline cbxracer30

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Re: Black gunk
« Reply #6 on: May 04, 2009, 02:11:31 PM »
Yea, Not sure if you can get it in your area  Berkybile 2+2 instant gum cutter. Spray it down in the pipe cover both ends and swoosh it around. This will get most of the wet oil out. If you can't get Gum Cutter then just cheap oven cleaner, spray itin and let it work for about 15-20 min. repet if there is alot of build up. try not to get it on the outside of the pipe. Then for the head part of the pipe you can get round wire brushes that attach to a drill motor, try and find one the same diameter as your pipe and run it in and out with the drill till the build up is gone
Yep, you can ride it - if YOU can start it !!

Offline stock500

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Re: Black gunk
« Reply #7 on: May 05, 2009, 03:12:44 AM »
Make sure the copper o-ring that seals the pipe to the cylinder is there.  I was having the same problem, and I didn't realize it was missing because the two o-rings on the heap pipe were there, and I didn't know there was another gasket.  I looked at the OEM chart and saw it, so when I put my bike back together it should be better. 
It's all in the wrist!  Save a tire, shift early!

Offline hughes

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Re: Black gunk
« Reply #8 on: May 05, 2009, 03:42:37 AM »
Before you make any jetting changes you'll need to check float height. low float height will allow to much fuel inside the carb bowl and the bike will run pig rich at low/mid range speeds. I have cleaned up the black splooge on a few bikes just by setting the float height. Not that much of big deal a really new bike but a 92 model it really needs to be checked. Also leaking crank main seals can make you think you have jetting issues. My 87 500 ran 32:1 premix, correct float height,a few jetting changes and never displayed the black splooge.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com

Offline cattamer

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Re: Black gunk
« Reply #9 on: May 05, 2009, 04:42:44 AM »
Thanks guys,The copper O-ring is there 500,thanks.Hughes how do you check and set the float height?I've had several 2-strokes and I've never known this,but I've never had this problem either.Are there any other signs to seals being bad?

Offline hughes

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Re: Black gunk
« Reply #10 on: May 05, 2009, 04:48:21 AM »
I don't have the service manual for your bike but in most cases with the carb bowl removed you will invert the carb and measure from the gasket base area to the top of the carb float. Maybe someone here has the manual and can give you the specs and other little details.
Open Class 2-Stroke Kawasaki KX500
Yamaha 2005 YZ250
Richard Hughes
Dirt Hammers - Online Off-Road Journal
hughes@dirthammers.com
http://www.dirthammers.com