1200 cylinder base gasket

jotajoe

jotajoe

Hero member
Location
Warwickshire UK
Good morning Fellas.

I have a full gasket set brand is Centauro and made to ISO 9002. The label says for 1000 and 1200 engines.

My crankcase is away at the moment for soda cleaning. I am wondering if I have a 1200 base gasket or a 1000 only

I measured with an "old wooden ruler"  :o the diameter of the holes and it is reading as 82mm.

Is that Ok for the 1200 or do I need another gasket ?


Cheers ..All advices gratefully received !

Joe
 
jotajoe said:
Now have to read up on the head gasket..I'll probably need one. The metal ring is a silver colour ..hmmm
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As far as I know the head gasket is the same for 1000/1200 machines. It has 80mm bore for 1200. 1000 (bore 75mm) has a shoulder structure similar to some drag racing engines and the gasket fits.
 
There is still some differences on some holes on three cylinder engines. I needed to gently punch some holes bigger for my SFC 1000 engine which has 9mm head bolts. I think those gaskets were made to elder 8mm version.
 
jotajoe said:
Cheers Red.

I'll order a 1200 base gasket for the job.

Now have to read up on the head gasket..I'll probably need one. The metal ring is a silver colour ..hmmm

: )

Joe
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After going through last years' head gasket disaster, I've found that the incorrect flat gaskets work fine if the liners are flush with the cylinder casting surface.  I now often resort to skimming the 1200 cylinders, they often show a dip or a bow at some point anyway, to use up existing stocks of the flat gaskets.  If your liners are recessed, you will need to source a gasket with the flame rings slightly thicker than the gasket itself.  Don't matter if the flame ring is copper or steel, both work fine.  If however, your liners protrude from the casting, it will be easiest to simply skim the barrel, Red is sure to have plenty of those "wrong" gaskets in stock.

Actually, these incorrect gaskets are superior to the originals imho.  They seal better and do not "give" when the head is torqued.  I have found that when checking head nut torque on a rebuilt engine, there is little to no change after 1000km, whereas the original gaskets often allow about a quarter to half turn when re-torquing.

piet

piet
 
MotoJouni said:
There is still some differences on some holes on three cylinder engines. I needed to gently punch some holes bigger for my SFC 1000 engine which has 9mm head bolts. I think those gaskets were made to elder 8mm version.
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Triples always had 9mm studs.  Gaskets are very often a tight fit, depending on maker.  I use a deep 9mm socket to push the gasket over the threads.

piet
 
sfcpiet said:
After going through last years' head gasket disaster, I've found that the incorrect flat gaskets work fine if the liners are flush with the cylinder casting surface.  I now often resort to skimming the 1200 cylinders.  If however, your liners protrude from the casting, it will be easiest to simply skim the barrel, Red is sure to have plenty of those "wrong" gaskets in stock.

Actually, these incorrect gaskets are superior to the originals imho.  They seal better and do not "give" when the head is torqued.  I have found that when checking head nut torque on a rebuilt engine, there is little to no change after 1000km, whereas the original gaskets often allow about a quarter to half turn when re-torquing.
piet
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totally agree with Piet, the 1.0mm "wrong" head gasket with the steel 1.0mm flame rings is my preferred head gasket to use on the 1200 engines we build, we skim the barrel face on those engines, is a very good head gasket once set up right, am worried that the supply of those may dry up though as Athena changed the design after Wolfgang visited them

Athena now produce another "wrong" head gasket, 1.5mm thick with copper coated steel flame rings at 1.8mm thick, causes cam chain joining issues as it is too thick, is handy to stock though as quite often find cylinder heads that have been indiscriminately decked in their past life so the thicker gaskets are handy to regain some height, need to make certain that you use slightly thicker O-Rings on the outer studs

and the 3rd head gasket version that Phil makes, 1.0mm+ gasket material, 1.3mm+ flame rings, needs some trimming to No 3 cylinder stud hole pattern to get it to fit, have used a few now on 1000 engines that had the recessed liners, seem to work okay

so in the end it is preferable to stock all 3 types of head gaskets
 
Joe - I've got plenty of 1200 base gaskets and 1 head gasket with raised flame rings and plenty of the non raised flame ring gaskets left if you need them - regards - Phil
 
AND >>>>>>>>>>>>>>>>>>
I do have my supporters for the solid copper head gasket
There are also plenty of detractors.

There are dozens od triples riding around happily with one of my solid copper gaskets installed,
Joe if you would like a solid copper one, or just to talk about them, then contact me, they are no longer advertised or openly sold, for a variety of reasons.
CLEM

0778 018464
01959 532316
 
redax5 said:
and the 3rd head gasket version that Phil makes, 1.0mm+ gasket material, 1.3mm+ flame rings, needs some trimming to No 3 cylinder stud hole pattern to get it to fit
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Had exactly the same issue with one of Phil's gaskets. Engine pissed oil from the head gasket like a fountain on first start up. I lifted the head again and adjusted the o-ring stud holes to get the o-rings more closely centred over the holes in the block, which fixed the problem.

To be fair to Phil, it wasn't a quality control issue. He had moved the o-ring holes radially outward to increase the width of the flame ring where the holes cut into it. There should still have been enough metal for the o-rings to seal against, even though they weren't exactly concentric with the holes. It probably seemed like a good idea at the time, but in my case it didn't work. Perhaps manufacturing tolerances in head, cylinder block and gasket all added up to allow at least one o-ring to miss the edge of the hole by enough to let it leak.
 
Dellortoman said:
Had exactly the same issue with one of Phil's gaskets. Engine pissed oil from the head gasket like a fountain on first start up. I lifted the head again and adjusted the o-ring stud holes to get the o-rings more closely centred over the holes in the block, which fixed the problem.

To be fair to Phil, it wasn't a quality control issue. He had moved the o-ring holes radially outward to increase the width of the flame ring where the holes cut into it. There should still have been enough metal for the o-rings to seal against, even though they weren't exactly concentric with the holes. It probably seemed like a good idea at the time, but in my case it didn't work. Perhaps manufacturing tolerances in head, cylinder block and gasket all added up to allow at least one o-ring to miss the edge of the hole by enough to let it leak.
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  Hi Cam - those were the thicker ones. Doing different gaskets now using a more flexible material and the original 1mm thickness. Have had a slight problem with some as Red and Keith have found that there's a slight misalignment of a few stud holes - have been onto manufacturers and they are looking into it - they reckon it's maybe some loose punches in the die - they are sending me a sample to (hopefully) correct this before supplying the next order. - Regards - Phil
 
No problem Phil. My issue was easily sorted. Are you still getting the thick gaskets made? They're handy for people like me with shaved heads, and I don't mean the Bruce Willis type of shaved head.
I probably should get another one to keep as a spare.
 
Dellortoman said:
No problem Phil. My issue was easily sorted. Are you still getting the thick gaskets made? They're handy for people like me with shaved heads, and I don't mean the Bruce Willis type of shaved head.
I probably should get another one to keep as a spare.
Click to expand...

read what I wrote, you can buy a 1.5mm Athena made gasket from Wolfgang that is correct in every aspect apart from being too thick, suitable for shaved heads




 
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