Leaking / blown crank seal symptoms?

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Richie Rich
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Posts: 32
Joined: Tue Oct 16, 2012 12:47 am
Location: Melbourne, Australia

Leaking / blown crank seal symptoms?

Post by Richie Rich » Sun May 18, 2014 10:19 am

Hi all, hoping someone here with a little more experience in these matters might be able to confirm what I believe must be a leaking crank seal on the front cylinder of my KR250.

The bike is a low km (4,900) jap import and clearly the engine has never been touched. I've been slowly recommissioning the bike but the focus has been the chassis, brakes etc. as the bike started and ran fine when I bought it, though I must admit I did wonder whether I should've had the engine pulled down for an inspection at least.

Anyway, the bike is basically finished and has come up a treat, it looks amazing and I'm very happy with it, except on its first little blast down the road it started spitting oil out of the lower pipe muffler, out the end and out the bolt holes that hold the muffler sleeve on. The oil doesn't appear to be two stroke so it must be gear box oil so I assume I have a blown or leaking crank case seal on the front cylinder. The muffler still has notice suppression packing around the baffle (which I assume aren't removable) and this is soaked in oil.

So, I'm no engine expert but is this the correct diagnosis or is this something else?

I read in the manual that you need to remove the rear cylinder & head in order to remove the engine from the frame, is this right?

Appreciate any advice form the experts.

Cheers, Richard

Image
1983 RZ350K
1984 KR250A
1985 GSXR750F
1989 TZR250 3MA
2010 Street Triple 675

Richie Rich
Light Smoker
Posts: 32
Joined: Tue Oct 16, 2012 12:47 am
Location: Melbourne, Australia

Re: Leaking / blown crank seal symptoms?

Post by Richie Rich » Sun May 18, 2014 11:42 am

One more thing, it isn't oiling the plug on the front cylinder which I would've thought would happen if a crank seal went? It also didn't blow much exhaust smoke at all and certainly no white smoke that I've read is also a symptom of leaking crank seals.
1983 RZ350K
1984 KR250A
1985 GSXR750F
1989 TZR250 3MA
2010 Street Triple 675

dougindoors
Heavy Smoker
Posts: 363
Joined: Wed Jun 03, 2009 9:12 pm
Location: rochester kent

Re: Leaking / blown crank seal symptoms?

Post by dougindoors » Sun May 18, 2014 6:59 pm

Is your gearbox oil level dropping? After many strips and rebuilds just about every thing replaced mine smokes more,from the front cylinder than the rear
1984 Kawasaki KR250A
no projects, OOPS!1987 Kawasaki AR125B4
Every 2 in 1 poeple are schizophrenic
If you can not fix it with a hammer it must be electrical
2 Smokey and they bandit

nigb
Light Smoker
Posts: 25
Joined: Thu Nov 12, 2009 12:17 pm
Location: Australia

Re: Leaking / blown crank seal symptoms?

Post by nigb » Mon May 19, 2014 2:06 pm

I bought a KR for a spares bike & crank seal had gone on that and it blew plenty of grey smoke (gearbox oil). From the description you give it doesnt sound like a crank seal to me. What I have noticed is as I leave my kr for long periods between rides it does smoke a lot on start up but soon clears a k or 2 down the road.

Given the low ks on your bike (in my experience they seem to self destruct around the 30-40k mark if not maintained) & the fact it hasnt been run for some time it might just need a good run? How far did you test ride it & how much oil is spitting out?

Might also be worth checking choke cable is operating on both carbs properly

Nice looking bike & they are great ride
2008 Ducati 1098
2003 Triumph Sprint
2003 KTM 450EXC
1975 h***a 400-4 (fully restored)
1984 KR 250

Richie Rich
Light Smoker
Posts: 32
Joined: Tue Oct 16, 2012 12:47 am
Location: Melbourne, Australia

Re: Leaking / blown crank seal symptoms?

Post by Richie Rich » Tue May 20, 2014 3:29 am

Thanks for the responses. A few others have also said I might be 'jumping the gun' on the crank seal diagnosis so will try a few other things first. Will remove the pipe and clean it out. Someone mentioned it might be a sticking oil check valve (not sure what that is but wil consult the manual).

It wasn't blowing much smoke at all and the gearbox oil doesn't appear to have dropped and nor did the old oil smell of petrol which someone suggested is another tell tale sign if crank seal failure. But I only rode it about a km or so. Oil was dribbling out the end of the muffler but the pressure was forcing it out of the bolt holes holding the muffler on - enough to spray a small amount over the rear tyre.

As I mentioned the muffler packing is soaked in oil so I'll rip this out (it doesn't appear as though the baffles are removable) when I clean the inside of the pipe.

Fun & Games!
1983 RZ350K
1984 KR250A
1985 GSXR750F
1989 TZR250 3MA
2010 Street Triple 675

scottricho
Newbie
Posts: 18
Joined: Wed Apr 11, 2012 7:17 pm

Re: Leaking / blown crank seal symptoms?

Post by scottricho » Thu May 22, 2014 7:58 pm

Its weird coz my bike did the same thing for a while then cleared itself up.
Im constantly watching the oil window to ensure there is no water contamination and the level stays the same.
have you done a test on the oil pump and synchronized the carbies?
I still have carby issues because it will only pull cleanly to the redline when I push on the choke after 7000 rpm
Bikes: 2x RGV 250 vj21 (pepsi/black)
2x KR 250A (reds)
h***a TLM 200
Suzuki Tc 120 1969 (project)
Suzuki DR 350 1992
kr1b1 1988
some others for the missus n kids

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