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Leaking base gasket

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Hey guys, in all of my years in Hondas I have never had any gasket failure before.

 

Was out riding yesterday and noticed blue oil coming from the base gasket and looked closer once o got her home, looks like the gaskets is sort of sucked in.

 

All oem rebuild on a barely used set of cases about 20 hours ago.

 

I ordered a cometic top end kit.

 

Anyone have experience with an issue like this?

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what gasket kit did you use previously ?



Oem, I'm nervous that something warped but it never over heated or was over torqued.

I did use some Honda bond I'm wondering if it wasn't mixed right and didn't get tacky enough allowing the gasket to move under load?

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why are you using gasket sealer on the base gasket ?



There was a small nic on the front of the right case near the exhaust, the leak is right below the left side transfer ports.

I used sealer as cheap insurance, perhaps to my demise a bit lol.

I'll post pics tonight.
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Soo after further investigation I found a pry mark on the case

Any ideas how to seal this? This was a Honda gasket with Honda bond

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Go easy with the hondabond just use a light coating.  Tightn it down good may have to even use two gasket or find one Lott thicker.  Hurting the sqishalitte Tiny bit be better than that. 

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The cometic gasket kit comes with a metal base gasket so I don't think it will seal that mark very good.  I would use an OEM base gasket and use a thin coating of Honda bond on the case where the seams come together and where that mark is.  You might be cautious on the cometic head gasket too because the cometic kit I got the dowel holes were too small on the head gasket and it just simply didn't fit. also the cometic base gasket is thinner than the oem 03 base gasket.  IMO, I would send it back and go oem.

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Update: the gasket got sucked in on both sides, something is not flat.


I'm going to lap the cases mating surface with a surfacing plate, masking off the crank area with the bottom end still in the bike.

Also sending the cylinder to get turned on the base gasket surface to insure its flat

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Update lapped cases with surface plate while engine was in the frame, I just moved the rod and has to re tape a few times. I checked the flatness with the surface plate and a flashlight.

Bike now has 10 hours since repairs and runs great.

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I personally prefer the cometic base gasket over the oem honda.  It is the only gasket on the bike that I can say that for(although I use cometic on the reed valve also because it is VForce).  I always seem to get base gasket leaks with the cheap honda paper ones.  The Cometic's seal perfect 1st time every time.

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Case looks like it has been sanded on to get rid of that groove.. Check it with a good straight edge before putting it back together.. Probably a low spot there.

Edited by mxsteve1968
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On 10/12/2017 at 10:14 AM, c-slak said:

I personally prefer the cometic base gasket over the oem honda.  It is the only gasket on the bike that I can say that for(although I use cometic on the reed valve also because it is VForce).  I always seem to get base gasket leaks with the cheap honda paper ones.  The Cometic's seal perfect 1st time every time.

+2.  Been using the thinner cometic base gasket since 97 with no issues on 97-03 CR250r's.  It was recommended to me by a local engine tuner.

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Case looks like it has been sanded on to get rid of that groove.. Check it with a good straight edge before putting it back together.. Probably a low spot there.

No leaks and proper squish = no worries in my book. Part of the reason why I love the rc valve Hondas, will hold 100% on a pressure test if proper. I check every rebuild. 1st time I checked a ktm 300 it wouldn't hold pressure at all. Those powervalves leak like a sieve.

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