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Top end rebuild 1978 r80/7

evojet

evojet

New member
So I am replacing the pushrod seals on my 78 r80/7. I ordered and specified which top end gasket kit I need.

Here is what I received
image.jpg

When I popped my cylinders off I have a metal gasket without the two small orings and the one big one. Had what looks like a bit of RTV on there as well.

image.jpg

Is what's installed the correct gasket and I was sent the wrong kit? Or is this the incorrect gasket installed on my bike and I should use what is in the kit?

Thanks in advance.
 
Not sure where you ordered your parts or where you got your part #'s . . .

I like the realeom.com site - just provide year/model of your bike and you'll get a visual for every part on your bike with BMW oem part numbers. That should help things - some parts made a long time ago are superseded with new part numbers.
 
I did a top end on my '78 R100/7...here's a link to one of my posts showing what was there when I took things apart:

http://forums.bmwmoa.org/showthread...opend-Overhaul&p=841785&viewfull=1#post841785

No base gasket or large o-ring for me. I suspect the previous owner of your bike installed a compression reducing base gasket. There should have been two small O-rings on the upper studs...a little RTV of some kind is usually required.

I ended up replacing the pistons with higher compression ones...I was concerned about what higher compression might need or issues down the line, so I installed a base gasket to reduce the compression back to around 8.8 instead of the 9.5 of the replacement pistons. IIRC my gasket was 0.67 mm thick.
 
kentuvman said:
Not sure where you ordered your parts or where you got your part #'s . . .

I like the realeom.com site - just provide year/model of your bike and you'll get a visual for every part on your bike with BMW oem part numbers. That should help things - some parts made a long time ago are superseded with new part numbers.
Click to expand...

Looks like that website is dead.
 
The cylinder looks stock...I see "1182" at the end of the mold number. See a similar picture of my 1000cc cylinder:

http://forums.bmwmoa.org/showthread...opend-Overhaul&p=841781&viewfull=1#post841781

Hard to see from your picture but is the iron liner separated from the cylinder along the upper part of the bore?

I was thinking that if that was a compression reduction gasket and you will be reusing the cylinders, be sure you get rid of the ridge at the top of the bore...that would have built up a ridge at the full range of the stroke.
 
20774 said:
The cylinder looks stock...I see "1182" at the end of the mold number. See a similar picture of my 1000cc cylinder:

http://forums.bmwmoa.org/showthread...opend-Overhaul&p=841781&viewfull=1#post841781

Hard to see from your picture but is the iron liner separated from the cylinder along the upper part of the bore?

I was thinking that if that was a compression reduction gasket and you will be reusing the cylinders, be sure you get rid of the ridge at the top of the bore...that would have built up a ridge at the full range of the stroke.
Click to expand...

I am going to get evrything jet washed and cleaned up.

image.jpg
 
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