Topic: copper head gasket

[195suz]

I know this may be a stupid question so, When running an oringed head due you have to run a copper head gasket or can you use a composite on a high compression engine cb750. If so who carries copper head gasket for a 73mm bore?

[dragracer]

I know this may be a stupid question so, When running an oringed head due you have to run a copper head gasket or can you use a composite on a high compression engine cb750. If so who carries copper head gasket for a 73mm bore?

I had Cometic to make several copper head gaskets for my 72mm block. It is o-ringed. I also had them to make some base gaskets in different thicknesses for the oversize sleeves so i could play with deck height. Unsure of who else custom makes copper gaskets but i'm sure another forum member will chime in to help further.

[jweeks]

Copper Gaskets Unlimited did my 73mm bore ones. Yes, I o-ring.

[bwaller]

I use an o-ring & copper gasket as well. Because the copper is soft it easily allows the o-ring to embed. The other benefit of a copper gasket is that you can order a smaller gasket bore and "size" tightly to your sleeve bore, can't do that with a steel fire ring on a composite gasket.

[cbr954]

Dynoman sells 73mm copper head gaskets and in different thicknesses.  He is very fast shipping too.

[johno]

Hi 195,
If you have your barrels o ringed allready be carefull running a composite, the heat ring is metal and if it sits on the O ring ( mig wire) it may sit too proud and not seal, if the fire ring misses the O ring and it is bedding into the composite that will be fine.

What the other guys have advised is all good to me , the only thing I must say if running a copper gasket definately get the barrels O ringed as the copper is soft and evan though the mig wire is only 12 to 15 though proud it bites in nice and gives good holding surface for the copper gasket.

I have a dillema at the moment on my 750 engine as its only 62mm bore and get to better flow I have scolloped the top of the bore down to the top of the top ring, I was planning to run the copper gasket but not much room for the o ring groove ? so may run composite with the two valve scolloped fire ring shaped bore and no o ring, use the copper as a spare.

[195suz]

Thank you everyone with your reply, lots of good information but since I have the experts ear is there antone still making 73mm pistons for the SOHC? I have a 3mm stroker crank with Carillo rods and a 385 lift cam.

[Big Jay]

Seems like everyone is moving away from copper gaskets and o'rings to the MLS gaskets. All those big 1700+cc nitrous pro mods are using MLS and no o'rings.

[195suz]

So who is making the MLS gaskets?

[Jerry Rxman Griffin aka MuthaF'er]

Check with CycleX

[cbr954]

Cometic is making the mls gaskets.  The ones from Dynoman are packaged from Cometic.  Dynoman offers more thicknesses and bore options then Cycle X does.  I have used them in my 836 and have one coming for my 970 build which they just got back in stock at Dynoman.

[HondaMan]

How well are those MLS head gaskets sealing the oil passages? Any long-term users here, yet?

[MRieck]

How well are those MLS head gaskets sealing the oil passages? Any long-term users here, yet?

I have one on my Hayabusa I changed 10 years ago (after porting the head)....no leaks there. Seriously Mark.....the cylinder deck and head surface must be flat and very smooth. The oil return holes have a nice embossed ring....far better than any composite....closer to those old OEM head gaskets with the copper sealing rings. MLS require the smooth, flat surfaces....there are a lot of guys that will slap old warped (and they old warp in many directions after 40 years) and have bad results. Of course many of those fellas will scream the loudest. You need heavy studs too....they are a good product.

[Bill/BentON Racing]

Samauto running MLS head gasket. Been in with 915 kit 2 seasons now! I have some Cometic NOS copper head gaskets anyone interested? Bill Samauto has a Stage IV+ head also!   Bill

[dragracer]

Samauto running MLS head gasket. Been in with 915 kit 2 seasons now! I have some Cometic NOS copper head gaskets anyone interested? Bill Samauto has a Stage IV+ head also!   Bill

Bill,

Can the MLS be reused?? Thats the only potential drawback i see to this type gasket. I've annealed copper gaskets and used there several times over.

Had MLS on my water cooled GSXR race bike. Sealed great but i bought another when it was time to pull the head to freshen up the valves.

[Big Jay]

I don't believe the design is meant to be reused, but guys on the busa boards say they have done it.

[Don R]

 I've reused mls on my big block chevy, 14.5-1 compression. 4.61 bore.