bike just doesnt seem right.

[kelcrist]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

[Polar-Bus]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

If you find you have transmission oil dissapearing and you see no external leaks, this is a tell tale sign you have a bad crank seal as well and might explain your excessive smoking. Don't know what you are premixing at, but I recommend 42:1 for the  average weekend play rider.

[Motorrad]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

Ive always wanted to find another set of cases, to "work on" ...

as Id like to be able to change the seals from the outside...

I think its doable... with alot of work

[Goat]

  however.........it has been blowing a lot more oil out of the exhaust lately

I wonder if the right side crank seal could be causing your troubles.

That's what I'm thinking. Leak down test for sure.

[kelcrist]

it doesnt use trans fluid but that doesnt mean the seal is 100%.    i have read the thread on crank seals and the leakdown tests........the seals that seem good but are not but heres the issue with  that.............   suppose you change the seals and they are 100%..... but after a few weeks/months/what ever they no longer pass these tests again but the bike still runs decent.     you trying to tell me that your goign to change those seals at every instance that you feel the seal is not right?     its all good in theory but thats not always real world feasible.    this bike prob hasnt had crank seals replaced in at least 5-6 years if ever.    ill update what i find as i have time to work on it. 

[Goat]

Crank seals don't see any transmission oil. The only lube they get is from the premix that gets sucked down there before being sucked into the cylinder. If they haven't been changed in 5+ years I'm betting that is the cause which can lead to other failures.

[Polar-Bus]

Crank seals don't see any transmission oil. The only lube they get is from the premix that gets sucked down there before being sucked into the cylinder. If they haven't been changed in 5+ years I'm betting that is the cause which can lead to other failures.

Doesn't the RH primary side crank seal come in contact with trans oil the resides in the clutch cover housing ? 

[Motorrad]

Crank seals don't see any transmission oil. The only lube they get is from the premix that gets sucked down there before being sucked into the cylinder. If they haven't been changed in 5+ years I'm betting that is the cause which can lead to other failures.

Doesn't the RH primary side crank seal come in contact with trans oil the resides in the clutch cover housing ? 

Yes

And shelf life of a nitrile seal is 5 years.    Living on a climate controlled shelf away from heat oil and sunlight... How long do ya think life in a motor is??

[Polar-Bus]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

Ive always wanted to find another set of cases, to "work on" ...

as Id like to be able to change the seals from the outside...

I think its doable... with alot of work

I did the lower end in my '97 KX250, and if I remember correctly there is a series of casting lips around the OD of the crankcase seal bores that only allow the seals to be installed from the inside of the case.    You could bore those nubs off and be able to install seals from the outside, but then my only concern thereafter would be the imfamous KX500 kickstarting "backfire" blowing the seals clean out of the bore(s) ! 

[Motorrad]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

Ive always wanted to find another set of cases, to "work on" ...

as Id like to be able to change the seals from the outside...

I think its doable... with alot of work

I did the lower end in my '97 KX250, and if I remember correctly there is a series of casting lips around the OD of the crankcase seal bores that only allow the seals to be installed from the inside of the case.    You could bore those nubs off and be able to install seals from the outside, but then my only concern thereafter would be the imfamous KX500 kickstarting "backfire" blowing the seals clean out of the bore(s) ! 

That would be step one.. The easy part if you will...

The lot of work part would be making some kind of retaining system like Honda uses..

[kelcrist]

well i have found the problem..................    i have an FMF spark arrestor installed.    i was doing some swapping around while servicing the suspension and found a loud rattle when i was moving the sub frame around.  turns out the pipe down the middle was broken off so the tail of the silencer was filling with exhaust and not moving out.   thats where the oil and goop was coming from.  i put on the stock silencer and its much better.  sounds crisp again and missing like before.  i havent had the silencer off in quite some time so no idea how long i was trying to tune around this issue.      so anyway just goes to show ya...............start with the  simple stuff.

[kaw rider]

it is not out of the question!!!      if it were a honda id just change them and not give it a thought....

Ive always wanted to find another set of cases, to "work on" ...

as Id like to be able to change the seals from the outside...

I think its doable... with alot of work

I did the lower end in my '97 KX250, and if I remember correctly there is a series of casting lips around the OD of the crankcase seal bores that only allow the seals to be installed from the inside of the case.    You could bore those nubs off and be able to install seals from the outside, but then my only concern thereafter would be the imfamous KX500 kickstarting "backfire" blowing the seals clean out of the bore(s) ! 

A set of locking plates would fix that problem.

[Goat]

well i have found the problem..................    i have an FMF spark arrestor installed.    i was doing some swapping around while servicing the suspension and found a loud rattle when i was moving the sub frame around.  turns out the pipe down the middle was broken off so the tail of the silencer was filling with exhaust and not moving out.   thats where the oil and goop was coming from.  i put on the stock silencer and its much better.  sounds crisp again and missing like before.  i havent had the silencer off in quite some time so no idea how long i was trying to tune around this issue.      so anyway just goes to show ya...............start with the  simple stuff.

Glad you found the culprit. So the pipe inside the silencer was broke and causing a blockage?

[Polar-Bus]

well i have found the problem..................    i have an FMF spark arrestor installed.    i was doing some swapping around while servicing the suspension and found a loud rattle when i was moving the sub frame around.  turns out the pipe down the middle was broken off so the tail of the silencer was filling with exhaust and not moving out.   thats where the oil and goop was coming from.  i put on the stock silencer and its much better.  sounds crisp again and missing like before.  i havent had the silencer off in quite some time so no idea how long i was trying to tune around this issue.      so anyway just goes to show ya...............start with the  simple stuff.

Awesome ! Ususally most people that come here asking why their bike runs like crap stems from a junk top end. Glad to read that you have a simpler to fix issue. Reminds me back in the 80's when I was racing MX , i left a paper towel in the carb to keep dirt out, and in a frenzy slapped the air filter back in without removing the towel !  The bike ran like $hit ! I was dead last in that moto took me an hour to figure out what a dumba$$ mistake I made ! 

[kelcrist]

well the broken tube inside the muffler wasnt necessarily causing a blockage.............it just wasnt allowing the exhaust to flow directly out of the silencer.  all the packing was blown out so the rear compartment was filling up before pushing the rest of the exhaust out.