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250RR crank seal leaking (I think)

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I've been struggling with a lot of smoke and drool.  I have worked through jetting and switched to pre-mix and nothing I've tried has an effect on the smoke and drool.  I have been successful at creating a lean bog and still a lot of smoke (switched back to my normal jetting).  I drained 500cc of transmission oil out (850cc went in).  I can't remember the exact mileage since the last oil change but it's not a lot.  Probably about 150-100 miles.  Very roughly speaking I think about 60cc of transmission oil is being used per gallon of gas burned (equivalent to about 60:1 oil ratio)  Thinking back on the smoke and drool problem, I think it's been changing slowly over time and getting gradually worse.

Some other things.  The bike smokes like craze after start up and never really clears out.  If I ride a slow technical section and then stop at an intersection, smoke pours out when I open the throttle all the way.  Then I leave a huge smoke screen.  It never really clears out either.  My riding buddies say my bike smokes a lot.  I've had a wide strip of drool all the way down the pipe and dripping on the swing arm for a couple of years and it seems to be getting worse (really bad).

The bike runs great if I don't jet it too lean trying to counteract the smoke. Never had a fouled plug.  Plug looks normal.  Maybe very slightly sooty.

So, what do you all think?  Do I have a leaking crank seal?

 

Thanks

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49 minutes ago, bryanaverill said:

So, what do you all think?  Do I have a leaking crank seal?

 

Sounds like it.

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Drain and measure the oil, put it back in, ride and repeat. That will tell you.

If you get a much reduced volume out 1st time then that's likely to be conclusive anyway.

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The smoke seems more gray and not straight blue like we all know and love.  It hangs in the air and smells like burnt oil.

I am now taking notes more carefully.  The trans oil will not drop drastically in one ride but I should be able to accurately measure my trans oil consumption over a few rides.

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For the cost and effort required, I would just change the crank seal and be done with it.

By saying that the trans oil drops every ride, you have answered your own question. It shouldn't be dropping at all between changes unless you have a leak.

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I will confirm if it actually is consuming trans oil.

Do I just remove the clutch cover and primary drive then change the seal and bushing o-ring?  Do I need to pay any special attention to the water pump or power valve regulator?

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If you are really tricky with a seal puller and had a large really deep socket to seat the seal you may be able to just get away with removing the right side cover, clutch, and pump. The new beta seal has a rubberized inner edge so when you heat the case to insert it actually melts and completely seals, it is pretty cool. It would also be best to have a new nut for the primary gear. It is worth a try before pulling the motor and splitting the cases.

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Defiantly no reason to disassemble the engine or remove can easily be done thru the clutch side. No reason to replace the nut, absolutely reusable.

Can try to use a standard seal remover first or a medium sized pick but usually below is what gets it done

Get a slap hammer,baro rent buy whatever, use the vise grip attachment, run a small self taping screw in each side of the seal clamp on and remove it.

Parts stores will rent you a slap hammer and a socket that will fit the seal if you dont want to buy anything

Edited by jmd426
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@bryanaverill
Does it look like this?
I may have the same problem.
My bike ('18. 300) didn't smoke at all a week ago. This is thick, white smoke and doesn't smell like 2T. Now it smokes whether hot or cold. 


 

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18 hours ago, Balkan boy said:

@bryanaverill
Does it look like this?
I may have the same problem.
My bike ('18. 300) didn't smoke at all a week ago. This is thick, white smoke and doesn't smell like 2T. Now it smokes whether hot or cold. 


 

generally gray smoke is transmission oil and white smoke is coolant. check your coolant levels. Also, transmission oil smoke burns your eyes quickly. My eyes are tearing now just thinking about it! 👎

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I didn't get a chance to ride this weekend.  My smoke does look like Balkan Boy's video but not nearly that bad. If I open the throttle half or more then I get a stream of smoke that looks like that.  The weird thing for me is that a change hasn't suddenly happened.  It has gradually evolved and gotten worse since the bike was new.

I have a couple of seal replacement questions: I like the drywall screw in the seal case method of retraction.  If you drill a pilot hole, what's the best way to contain the drill chips?  What is the tightening torque of the primary drive retention nut?  I really want to use an impact driver to remove the nut.  It that a really bad idea?  The advise against impact removal seems a little impractical to me.

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You can remove the clutch plates and use a clutch holder and a cheap harbor freight electric rattle gun with standard socket. It won't generate too much torque and won't hurt anything. Yes some super powered air gun most certainly could with an impact socket.

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On 9/30/2019 at 4:43 PM, bryanaverill said:

I didn't get a chance to ride this weekend.  My smoke does look like Balkan Boy's video but not nearly that bad. If I open the throttle half or more then I get a stream of smoke that looks like that.  The weird thing for me is that a change hasn't suddenly happened.  It has gradually evolved and gotten worse since the bike was new.

I have a couple of seal replacement questions: I like the drywall screw in the seal case method of retraction.  If you drill a pilot hole, what's the best way to contain the drill chips?  What is the tightening torque of the primary drive retention nut?  I really want to use an impact driver to remove the nut.  It that a really bad idea?  The advise against impact removal seems a little impractical to me.

I've been trough this last week, and it seems I have to do it again.
My smoke is most likely the result of a blown central gasket. We've likely made a mistake when we greased the new gasket on assembly. 

Your issue is consistent with the faulty seal on the gearbox side. 
You can use an impact gun on the primary gear nut, just don't forget it's a reverse thread. 
You'll need a tool to hold the flywheel (and the flywheel puller before that) on the other side. Be careful with the Bendix on disassembly as it can get jammed against the case. Heat gun is handy for separating the crank and other tight fits. 
I haven't taken out my bearings or seals because they were in perfect shape. 

Re-torquing the primary gear nut is a bit difficult if you don't have a decent tool to jam the gears. I want to make one like the factory tool, but I forgot to measure the gears when I had them out.
Manual says to torque the nut at 160Nm. This seems way too much to me. A lot of torque suggestions in the Beta manual are unusually high. That nut barely has three threads. I torqued mine at 100Nm. Choose your own number, and follow the steps in the manual otherwise. 

Edited by Balkan boy
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Never grease paper gaskets imo, if anything spray with cooper coat spry tack

A penny or anything softer than the gears can be placed in between the primary gear and clutch basket gear when torquing the nut

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If its pulling past the seal it'll load up heavy with oil after a long wfo pull vs. cleaning out.  

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19 minutes ago, jmd426 said:

Never grease paper gaskets imo, if anything spray with cooper coat spry tack

A penny or anything softer than the gears can be placed in between the primary gear and clutch basket gear when torquing the nut

I have no idea why we did it.
We bought agreed that it's not generally done, and then we did it. 
Lesson learned.

I used a soft aluminum plate between the gears, but I was very nervous doing it. Fit is never perfect, and it can slip or chip a gear. 
Primary gear or any of the gearbox gears is around 50$, btw.

One more thing.
Taking an engine out and back in is a four hands operation.
I suppose it could be done solo with suspension straps or engine jacks, but it's a chore.

Edited by Balkan boy
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I think my problem is mostly, but not all, jetting.

I don’t have good records of my transmission oil change, so I don’t really know how many miles it took to consume 300cc of transmission oil.  I will track it closely and then decide if I need a new crank seal.

I changed to a NECW(3) needle and 160 MJ.  The bike ran awesomely, and I didn’t notice the top end being too lean.  I almost never open the throttle all the way and rip.  I’m just a trail plodder.  The bike eventually cleaned out and was running normal smoke levels by the end of the day.  I get a little sploodge but all my bikes have.  Probably due to my plodder pace.

The prior jetting had an off-idle bog and then would catch and run. NECJ(2), PJ: 38, MJ: 165, AS: 1.0. I noticed that I would twist the throttle quite a ways in compensation for running badly.  The bike smoked and sploodged a lot with this “lean” jetting.  Maybe because I was twisting the throttle open so much.

I ran the NECJ(3), PJ: 38, MJ: 165, AS: 1.5 for a long time but always had a lot of sploodge.  It was probably a little boggey too but not obviously a problem.

The NECW needle and 160 main seem to work a lot better for me and my riding pace.  The throttle is very responsive, and I barely crank it open most of the time.  I’m not going to try to explain the MJ when some people are running 165 to 175.  160 just works for me.  Smoke level normal for now.

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On 10/7/2019 at 8:19 PM, bryanaverill said:

I think my problem is mostly, but not all, jetting.

I don’t have good records of my transmission oil change, so I don’t really know how many miles it took to consume 300cc of transmission oil.  I will track it closely and then decide if I need a new crank seal.

I changed to a NECW(3) needle and 160 MJ.  The bike ran awesomely, and I didn’t notice the top end being too lean.  I almost never open the throttle all the way and rip.  I’m just a trail plodder.  The bike eventually cleaned out and was running normal smoke levels by the end of the day.  I get a little sploodge but all my bikes have.  Probably due to my plodder pace.

The prior jetting had an off-idle bog and then would catch and run. NECJ(2), PJ: 38, MJ: 165, AS: 1.0. I noticed that I would twist the throttle quite a ways in compensation for running badly.  The bike smoked and sploodged a lot with this “lean” jetting.  Maybe because I was twisting the throttle open so much.

I ran the NECJ(3), PJ: 38, MJ: 165, AS: 1.5 for a long time but always had a lot of sploodge.  It was probably a little boggey too but not obviously a problem.

The NECW needle and 160 main seem to work a lot better for me and my riding pace.  The throttle is very responsive, and I barely crank it open most of the time.  I’m not going to try to explain the MJ when some people are running 165 to 175.  160 just works for me.  Smoke level normal for now.

This post gave me a bit of hope, so before tearing down the engine again, I topped up the gearbox oil (300ml as well), put fresh fuel at 2% mixture, tweaked the air screw and would you believe it ... 
No smoke!

 

Even better, bike ran perfectly. Very progressive power delivery and strong response. 
All my woes started when I started changing needles and fiddling with the carb. I'm back on stock settings now, and I'm not touching it without a damn good reason.  

 

 

Edited by Balkan boy
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