whens the last time you repacked the muffler??
Hows the plug look??
does it run good otherwise??

************************
You need a thneed
From Once-ler Industrys
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otherwise sure, do topends on them... I mean there almost 12years old..

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You need a thneed
From Once-ler Industrys
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before I sold my bikes and got 4-wheelers I had a 85 CR125 & 86 CR250 they both had the same symtoms as yours,it turned out to be the right hand side crank seal, Iv'e also heard thqat it could be the reed valves , what you need to do is change the crank case oil (mesure it out exactly) run the bike for a while (ride for a hour or so ) then see if the same amount of oil comes out that went in, if its low replace the crank seal if its all still there check your reed valves.

Hope this helps

Ride hard, Lifes short

 

Eric, the most common cause for the black spooge you're talking about is jetting. On older bikes like your's the jets could be gummed up, or have build up of varnish. I would clean the carbs first with a good carb cleaner, letting the jets soak for awhile, including the pilot jets. If this does'nt fix the problem, I would try jetting a little bit leaner.
good luck

 

YOU ARE EIther running too rich or you are not riding hard enough. most likely its the latter of the two. you need to repack the muffler. take them apart and burn the core until the spooge cracks off. its ok for the pipe to glow it will also smoke alot so do it in a well ventilated area with a propane torch. then take a wire wheel to the core so you can see all the perforations, put back together with muff repack. if you have 12 yrs on the top you def need a rebuild. i replace mine every 30 - 50 hrs and they are beat. you should be riding the bike in band all the time if not you get build up of fuel that is not fully burned. my old bike used to do that all the time, its because i rode like a girl. when i go riding if i am in woods alot i hit the strait and keep it pinned for abou 10 secs or more so she gets cleaned out. never fouled a plug, seized a piston, or blown a motor. she bring the front up in fifth easy. but you have to use good oil and keep the motor fresh. on 12 yr motor it will go ba ba buieeeeee, clunk clunk. my opinion

 

rebuilding the top end that often is not necessary either....sh!t we would be rebuilding ours every weekend after riding...We can usually put a couple summers on a good top end before it needs to be rebuilt....

but yes its usually build up of some sort....try one step up on the plug...maybe it will burn a bit better....

AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

my top ends got at least 3 seasons of riding damn near every day on it and its fine, comp still exelent

if you don't cheat, yer just cheatin yerself

 

Thanks for all of the advice. The bike that is really oozing is my wife's bike. Maybe I just need to do a few laps on it to clean it out next time we go riding. I will replace the packing before we ride too. I do plan on cleaning the carbs and replacing the top ends on both bikes. Are their any web sites with good info on replacing top ends and carb rebuilding/cleaning?

Eric
My home page http://www.off-road.com/~estegall
Off-Road.com's TLC Section http://www.off-road.com/tlc

 

what do ya wanna know?? The guys here can tell ya most anything at this point...

some websites out there have pictures...but they are not always the best...


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

get the manual /wwwthreads_images/icons/laugh.gif

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You need a thneed
From Once-ler Industrys
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ya know of all the retorts back that I hate...the infamous get the manual has got to be the lamest one...

the manuals for the most part do not tell someone how to do something...as a matter of fact many of the manuals dont tell ya dick....



AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

I finally had to time to take the top end apart on the 90 CR125. Here is what I found.

--The spark plug was a dry looking black.
--The reeds looked like they were fine (no broken ones).
--No carbon on the head.
--Slight dry carbon buildup on the top of the piston.
--When I removed the HPP cover (?) on the right side to disconnect the linkage, tons of black oil-ish stuff oozed out. Looks similar to what is oozing out of the exhaust pipe (sticky and nasty). The chamber was filled with this oil stuff....is this normal?

From what I could see, the connecting rod has some left-to-right play, but no up and down play. The piston seems to slide left-to-right on the wrist pin and has some play if I rock it on the wirst pin as well.

--I removed the cylinder and the bore looks good (still has cross hatches and no vertical scratches).
--No scratches on the piston skirts.
--From what I could see, the crank looked really clean. No oil. So this would seem like the crank oil seals are still good. (meaning the black goo is probably 2 stroke oil = carb issues?).

So what is the next step for the top end?
--Buy a top end kit (new piston, ring, clips, bearing, wrist pin).
--Buy a top end gasket kit (cyl base, head, ???)

Any recommendations on which brand to get and who to order from?

I guess I should put in a new top end and then work on the carb. Take it apart, clean it, and reinstall it. Do I need to buy a rebuild kit for the carb as well? If so, what does it come with?

Thanks again for any help.

Eric
My home page http://www.off-road.com/~estegall
Off-Road.com's TLC Section http://www.off-road.com/tlc

 

Did you ever repack the muffler???
There are some stupid generic manuals out there, but if you get the HONDA service one you'll see what I mean.... you get what you pay for!!

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You need a thneed
From Once-ler Industrys
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If the insides are nice as you say...then WHY rebuild it? The black goo is most likely 2 stroke oil not burning up....look into the type of oil and mixture you are using...manual isnt going to tell you dick about black ooz....

maybe break down and call the local shop??


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

...it would have told him to repack the slicener /wwwthreads_images/icons/smile.gif

does Yamaha make a service manual for there bike.. not a generic one that covers diffrent models??? Like Honda does??

Please go to a honda shop and look at the manuals that HONDA makes, they are super informitive and give you ALL the info you need/wwwthreads_images/icons/smile.gif they are like 60$ usd though..

Not to be an A-hole, but please dont even respond untill you've looked at a REAL manual, cause your right, the generic ones do SU(K and they give the good ones a bad name.

KaN't wE AlL GiT AlOnG ??

************************
You need a thneed
From Once-ler Industrys
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The muffler on the bike was brand new. 3 rides later is when the new muffler began to ooze again.

Eric
My home page http://www.off-road.com/~estegall
Off-Road.com's TLC Section http://www.off-road.com/tlc

 

KyRon, I dont mind referring to a manual here and there...but people come here for help and as long as they try we should help them...dont become one of those guys that always sed rtfm....I really hate that...the internet and these boards are here to help people...not to tell them to go buy a manual...
if you have advice give it...if you dont, then well...dont offer the advice to go buy a manual....

manuals for the most part are not worth ****t...
the best place for getting things done right are people that have done them and can offer suggestions and ideas to better serve our friends and brothers in riding...


AirBorn!!
The good Lord giveth and the Eco-Nazi's Taketh away!
United we stand..Divided we fall..LETS UNITE!

 

SINCE YOU TOOK IT APART I WOULD at least put rings on it. you def have to replace gaskets. i would go with stock piston and rings for replace. check your jetting and clean your powervalve out with gas or some sort of solvent. the muff should def not be oozing after three rides.

 

I'd take the piston and cylinder and get them mic'ed just to be sure. A manual is handy for torque specs and stuff like that. I was impressed with the manual that came with my YZ but the damn thing is written in three languages so it's a little tough getting through. Unless of course you can read french and german.

 

I found an article from the june 1985 issue of dirtbike on the issue of exhaust pipe maintenance. It states that one of the symptoms of an exhaust pipe leak is "all sorts of liquid residue".
The reason i got the mag was because my ktm was reviewed in it, and wow, I had that oily black stuff all over the front of my engine by the exhaust port, and by my pipe connection... what a bonus... that oily goop fell into the catagory of "all sorts of liquid residue".
Anyway i don't know what the cause is, or if the bike is soppose to do it at all, but i tried their fix... and it worked on the black stuff (although it didn't give me a power increase like they promised).Here it is.
You clean off the pipe connections and put a good amount of high temp silicone on the sealing surface, and let it dry befor riding.
The article didn't explain why the stuff is there, but at least it comfirmed it's presence, and since it's Dirtbike you can bet that the bike they were working on was in good condition.
I would post the article but I don't have a scanner, sorry, I hope this helps anyway.

ktmbk
83 ATC 250r, 84 atc 250r (parting out), ATC 185s, 85 Ktm 350mxc

 

Now that I think of it, I don't remember seeing the rubber gasket between the exhaust pipe and the muffler......I wonder if that could be a factor? I am sure this would be a source of an air leak and if the article is right, it could be the problem. Thanks for the tip.

Eric
My home page http://www.off-road.com/~estegall
Off-Road.com's TLC Section http://www.off-road.com/tlc