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Seeing oil seeping from head bolt.


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#1 KreepaZoid

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Posted 19 August 2014 - 02:13 PM

On my M12 ( K750) in the last few times ive started it, I am noticing oil seeping from a head bolt , and last night noticed a tad bit of oil between the head and cyl.

This a head gasket issue?? If so who is a good source for gaskets for these??

I am not so sure its just a loose bolt, but suppose that is also a possibility

#2 dcsob

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Posted 20 August 2014 - 02:08 PM

just a heads up for you. If the crankcase breather hose is restricted or kinked in any way I have discovered (Eureka) it can and will force oil out onto that very spot. it can make for a very big mess on the leg involved.Check your tourque settings on bolts involved. Can't help on gasket as I have a '99 ural.

#3 MotoJ

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Posted 21 August 2014 - 01:59 PM

i would pull the head and check for a crack. These side-valve cylinders like to crack radially from the bolt holes towards the bore or towards the fins. Towards the bore will cause oil seepage.

I like the two part copper or aluminum and heat resistant material gaskets. They are a little thicker than just aluminum or copper, but they squish nice and create a great seal.


That said, I can't find them online right now. Here's a source for plain copper:

http://www.sidecarpr...per_gaskets.jpg
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#4 haj

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Posted 22 August 2014 - 05:01 AM

Hey,

I had that problem before.. I kind of ignored it at first..
After changing cylinders (I had a piston burn) I still had it... After a while I got a new head (which also solved the problem with a few broken fins), then it stopped..

I'm unsure where the oil came from...

Kind of early K750.
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Dnepr K750 1956 (it says on the polish papers, damn lies! must be from the 60's)
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#5 KreepaZoid

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Posted 22 August 2014 - 06:49 PM

Thanks guys.....Will check torque on bolts and prob pull the head if those aren't obviously loose.

Maybe I will snap a pic and post

#6 KreepaZoid

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Posted 23 August 2014 - 07:21 AM

Guess I can't embed pics in a post... At least I can't see how to do it with my phone

Anyway oil is only coming from one bolt. Anybody have the head torque spec for a K750 or MT12 motor??

I haven't found an English  manual for mine yet.
.

#7 KreepaZoid

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Posted 29 September 2014 - 01:41 PM

Looking like I am going to have to replace a head gasket, and possibly rings....anyone have torque specs for these flatheads?? I have a lot of info but no torque spec..

Thanks in advance.

#8 KreepaZoid

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Posted 09 February 2015 - 11:08 AM

Finally have an update. Been slowly tearing down the bike and changing its look a bit, but yesterday had finally gotten the time (after waiting a mere 5 weeks for my gasket set to arrive ) I finally got my head gaskets changed out!  Everything inside looked fantastic, so I got it all buttoned up now, BUT does anyone know the actual torque spec on the heads??  I have a chart but its not for a K750.  I went with the 11.6 pounds as mentioned in the chart but let me know if it actually needs to be tighter.

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#9 KreepaZoid

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Posted 09 February 2015 - 11:08 AM

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#10 KreepaZoid

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Posted 09 February 2015 - 11:09 AM

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#11 TassieChris

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Posted 10 February 2015 - 05:55 AM

Hi Kreepazoid
I reckon 11 foot pounds is too loose.
I had a similar problem with my M72 which is very similar and actually has k750 heads fitted and I did mine at 40 foot pounds.
The recomendation I got on the forum was 32 nm which is about 42 foot pounds so I'm pretty confident its about right - All running fine at the moment.
.
You can read the thread here
http://www.russianir...showtopic=15761

cheers
Chris.

#12 KreepaZoid

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Posted 10 February 2015 - 10:52 AM

Thank you Chris.

Yeah the 11.6lbs seems a bit light, but I figured I would start there then ask rather than crushing the new gaskets

Thanks a bunch.

#13 Serious Black

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Posted 11 February 2015 - 10:47 AM

I use 32Nm. And don't forget the washers under the bolts. If I remember right they are thicker than normal. I changed my bolts out for Allen bolts in 12.9 steel as I have a Chang Jiang and I have seen the Chinese bolts break. Soviet steel is usually OK on K750s but have a look at the bolts for necking anyway as the bike is quite old. If you change out the bolts run a tap down the holes before fitting the new bolts.
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#14 KreepaZoid

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Posted 11 February 2015 - 12:55 PM

View PostSerious Black, on 11 February 2015 - 10:47 AM, said:

I use 32Nm. And don't forget the washers under the bolts. If I remember right they are thicker than normal. I changed my bolts out for Allen bolts in 12.9 steel as I have a Chang Jiang and I have seen the Chinese bolts break. Soviet steel is usually OK on K750s but have a look at the bolts for necking anyway as the bike is quite old. If you change out the bolts run a tap down the holes before fitting the new bolts.

Thank you!




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