mouth
L plate rider.
Posts: 10
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Post by mouth on May 6, 2012 23:28:35 GMT 1
blown crank seal 500km on rebuild what could cause this?
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Post by arrow on May 6, 2012 23:30:55 GMT 1
Not fitted correctly.
worn crank.
worn casings.
Fitted wrong way round.
Seal not lubed correctly.
Crap quality seal (unlikley).
Debris in the engine on rebuild.
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mouth
L plate rider.
Posts: 10
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Post by mouth on May 6, 2012 23:58:30 GMT 1
how about excessive oil in the tranny? just drained the oil and had more than two liters and it's blue is it possible for two stroke oil to get in there?
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Post by arrow on May 7, 2012 0:15:21 GMT 1
More like the seal on the oil pump shaft I think.
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Post by loctite on May 7, 2012 0:53:55 GMT 1
how about excessive oil in the tranny? just drained the oil and had more than two liters and it's blue is it possible for two stroke oil to get in there?
this happened on mine but caught it in time
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mouth
L plate rider.
Posts: 10
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Post by mouth on May 7, 2012 0:57:15 GMT 1
are you saying it's not the crank seal but the but the oil pump sucking tranny oil ?
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Post by arrow on May 7, 2012 1:38:02 GMT 1
Gravity fed 2T oil passing into the gearbox I think. The oil pump will not suck in transmission oil.
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mouth
L plate rider.
Posts: 10
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Post by mouth on May 7, 2012 1:59:54 GMT 1
that's what I thought so to my other question can excessive oil blow the crank seal.
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Post by bare on May 7, 2012 3:06:51 GMT 1
Yess... especially if either of the cranks is Hooped :-)
IMO 500s are horrid abominations.
But then I currently (happily) don't own one :-)
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mouth
L plate rider.
Posts: 10
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Post by mouth on May 7, 2012 3:27:30 GMT 1
it's a 82 RD350LC.
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Post by midlifecrisisrd on May 7, 2012 21:00:37 GMT 1
What makes you think the crank seal is blown?
Is it just because of the oil level and spitting oil out the breather ( this is what happens when oil pump drive seal goes ) or is there something else.
Steve
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mouth
L plate rider.
Posts: 10
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Post by mouth on May 8, 2012 0:13:06 GMT 1
no it's definitely the crank seal billowing smoke out the left pipe the smell is obvious I just wondered if there was a connection but seems their two separate issues seems possibly the oil pump shaft seal is the culprit now as far as the left crank seal I heard it can be replaced externally is this true.
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Post by rdstars on May 8, 2012 0:17:45 GMT 1
If it was me I would strip and rebuild/replace the motor, at the same time you can check your mains etc. The engine is really simple to rebuild, changing all your seals and new gasket set should set you back around £100 and then maybe if you need a few other little bits. That way you can be safe that it is all done right.
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Post by midlifecrisisrd on May 8, 2012 12:52:10 GMT 1
no it's definitely the crank seal billowing smoke out the left pipe the smell is obvious I just wondered if there was a connection but seems their two separate issues seems possibly the oil pump shaft seal is the culprit now as far as the left crank seal I heard it can be replaced externally is this true. Afraid not, you will have to totally strip it and split the crankcases. As said it is quite simple and few special tool required. Steve |
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Post by rich on May 8, 2012 12:56:37 GMT 1
Left hand seal is open to the air so won't cause excess smoke. It will cause lean running though so try spraying some WD40 behind the flywheel while the bike is running and and see if the revs change. And no you can't change the seal externally as the seals have an outer ridge that sits in a groove in the crankcases. However, in my experience failed crank seals are a bit of a red herring and tend to last for years but I always replace them while the motor is spart.
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Post by midlifecrisisrd on May 8, 2012 14:00:49 GMT 1
It could be pumping forces driving the oil through the seal.
I'd try fixing the pump seal then run to see how it is then do a plug chop to see if it is lean on that side.
Had an engine I rebuilt and stored, oiled the crank heavily and it leaked oil out the left seal but once fitted had no problems.
Steve
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