99 CR250 transmission oil leak?

tbgonz
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tbgonz
Edited Date/Time 2/13/2016 3:08pm
I bought a 99 CR250 and was able to get a solid ride on it a few weeks ago. I've finally had time to do a post-ride maintenance. It smoked a good bit during my ride, a good amount of sponge coming from silencer that got all over my swingers (may just need to replace packing) and the power fell flat at high rpm's. The power finally busted out on top after pushing her a good bit. Almost like it needed to just run hard to clear whatever was holding it back. Still wasn't perfect though. The thought for many of these issues was that i was running my gas too rich combined with silencer needing repacking. I warmed my bike up and took the oil check bolt out. I added 10oz of tranny oil before oil came out of the check bolt.

Could this all be a sign that a crank seal or something maybe worn and tranny oil getting into cylinder?
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mb
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mb 12/7/2015 4:23pm
12/7/2015 4:23pm
Depending on the position of the bike while you used the check bolt could account for the difference. Don't know how much capacity the CR has but 10cc out of 750 on my YZ wouldn't have me very concerned (unless you topped off the check bolt before riding, provided you used the same exact measurement procedure).
tbgonz
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tbgonz 12/7/2015 4:39pm
12/7/2015 4:39pm
mb wrote:
Depending on the position of the bike while you used the check bolt could account for the difference. Don't know how much capacity the CR has...
Depending on the position of the bike while you used the check bolt could account for the difference. Don't know how much capacity the CR has but 10cc out of 750 on my YZ wouldn't have me very concerned (unless you topped off the check bolt before riding, provided you used the same exact measurement procedure).
Yea bike was on its stand when changing the oil before my ride and in the same position when checking oil today. I put in 10oz which is almost 300cc. The bike's symptoms combined with the loss of tranny oil is what is concerning me. Trying to come up with a diagnosis.
Paw Paw 271
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Paw Paw 271 12/7/2015 6:23pm
12/7/2015 6:23pm
Sounds like a crank seal on the clutch side is leaking. You can pull the cylinder and look under the piston crown and see if there is a Black deposit on it. If so, the most likely that seal is leaking.
The poor running can be from the carb float level being set too high or the float needle may be leaking.
What does the spark plug look like after a hard run?

Paw Paw
tbgonz
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tbgonz 12/7/2015 7:05pm
12/7/2015 7:05pm
Paw Paw 271 wrote:
Sounds like a crank seal on the clutch side is leaking. You can pull the cylinder and look under the piston crown and see if there...
Sounds like a crank seal on the clutch side is leaking. You can pull the cylinder and look under the piston crown and see if there is a Black deposit on it. If so, the most likely that seal is leaking.
The poor running can be from the carb float level being set too high or the float needle may be leaking.
What does the spark plug look like after a hard run?

Paw Paw
pulling the cylinder is a bit beyond my expertise, unfortunately. I've taken apart the carb, cleaned it out, adjusted the float and replaced a gasket. got the gas leak from the carb to stop. i think all that is good now. looking like right side crank seal may be the culprit. do they have to split the cases for that? i'm really hoping i'm not looking at too much $$$ to fix. ready to just ride regularly again! Smile

thanks paw paw

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Paw Paw 271
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Paw Paw 271 12/7/2015 7:54pm
12/7/2015 7:54pm
No the cases don't have to be split to replace the seal, but there will still be a good bit of labor as the clutch side cover and many parts inside the cover have to be removed to get to the seal. That takes a little bit of time and these jobs are time consuming at the shops.
I would suggest you pick up a service manual for a few dollars and then do the job yourself. You will be many dollars ahead. If you can't work on the bike yourself, it will become a money pit.
So, it's time to learn how to do things on your bike.
You should be able to do this job for about $100 including the manual, the oil, the gaskets and the seal in just about 2 hours. The shop is going to charge you much more than that just in labor then add on the parts.

Paw Paw
mb
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mb 12/8/2015 6:46am
12/8/2015 6:46am
Sorry, reading comprehension fail. I agree with Paw Paw. Buy the manual, read over it to see all the tools and parts that will be required. Get your tools ready and lay out a clean work space. Tackle it on a lazy Sunday and take your time, you'll do just fine.
tbgonz
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tbgonz 12/8/2015 8:38pm
12/8/2015 8:38pm
mb wrote:
Sorry, reading comprehension fail. I agree with Paw Paw. Buy the manual, read over it to see all the tools and parts that will be required...
Sorry, reading comprehension fail. I agree with Paw Paw. Buy the manual, read over it to see all the tools and parts that will be required. Get your tools ready and lay out a clean work space. Tackle it on a lazy Sunday and take your time, you'll do just fine.
Thanks for the encouragement guys. I have a service manual. I'll have to give it a good read and see how I feel. So from what I've read online its sounding like a right side crank seal issue. Ya'll agree this is the most likely culprit?
tbgonz
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tbgonz 12/8/2015 8:46pm
12/8/2015 8:46pm
just curious, has anyone taken their bikes to MMI (motorcycle repair school) for servicing? Curious if they would do labor for free. I'm curious if this is a good and cheap option if my skills end up subpar.
tbgonz
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tbgonz 1/29/2016 5:06pm
1/29/2016 5:06pm Edited Date/Time 1/29/2016 5:06pm
I think I've done everything shy of actually changing the crank seal to see if it helps with the smoke. It's time I bite the bullet and change that sucker isn't it? Here's a video from today after i repacked and cleaned a crazy amount of carbon out of my silencer. Not a whole lot of smoke when idling but sure seems to come out after a rev and return to idle.
tbgonz
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tbgonz 1/30/2016 3:27pm
1/30/2016 3:27pm Edited Date/Time 1/30/2016 3:30pm
i finally just took it to a shop to figure out whats up once and for all. if the crank seal is leaking the dude was talking about rebuilding the whole motor with new gaskets/seals. is that normal? seems like it would be way more expensive than just replacing that bad seal. i understand fixing that one seal doesn't necessarily mean there isn't another one that needs to be replaced too, so thats a risk. also, is $85/hr for labor normal? this is my first bike in 10yrs so i don't remember prices on everything.

if this estimate is over $350 i'm attempting this crap myself. everyone else online just seems to replace that one seal and surrounding gaskets.
tbgonz
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tbgonz 2/13/2016 3:08pm
2/13/2016 3:08pm
Good news for anyone who cares lol. The bike is fixed! Turns out a bolt holding the gears to the crankshaft was loose. If that thing had slipped out my engine would have been toast! This was also causing transmission oil to leak into the cylinder and cause the bike to run like crap. The bolt, crank seal and some other seals were replaced, I repackaged the silencer and she ran like a champ today! No accessive smoke and literally no oil on my swingarm after several hours on the track. Woohoo!

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