Topic: Modern Head Gaskets

[John G]

In some cases a modern head gasket does not require retorquing. Are there any available for the 1976 CB750K ?

[newday777]

Yes. MLS from CycleX and others.

[newday777]

http://www.cyclexchange.net/Engine%20Parts%20(Non-Cafe-Gaskets).htm

[BenelliSEI]

http://www.cyclexchange.net/Engine%20Parts%20(Non-Cafe-Gaskets).htm

I’ve read all the CyclEX gasket info and I am going to order a set for the top end of my current project. Their detailed descriptions of their product and attention to providing high quality seems apparent. Has anyone else used these products with good results?

[HondaMan]

I like [best] the ones from Vesrah. I have had quite some troubles with the MLS gaskets (and more engines sent to me with troubles FROM an MLS gasket).
PM me with your mailing address: I will also send you 2 O-rings that you MUST use with modern head gaskets, as they are ALL thicker than the OEM version. The OEM gaskets were 0.8mm thick, and modern ones (without asbestos, now) are all at LEAST 1mm thick. This will make the oil ports at the back of the cylinders leak oil in use. The thicker O-rings will prevent that.

It will also help a lot (if you have the cylinders off) to have the top of the cylinder block milled off 0.010" and the head surface milled flat to match.

[Handlebar]

1200 miles on a Cycle X gasket and rebuilt head and no sign of failure.

[BenelliSEI]

I like [best] the ones from Vesrah. I have had quite some troubles with the MLS gaskets (and more engines sent to me with troubles FROM an MLS gasket).
PM me with your mailing address: I will also send you 2 O-rings that you MUST use with modern head gaskets, as they are ALL thicker than the OEM version. The OEM gaskets were 0.8mm thick, and modern ones (without asbestos, now) are all at LEAST 1mm thick. This will make the oil ports at the back of the cylinders leak oil in use. The thicker O-rings will prevent that.

It will also help a lot (if you have the cylinders off) to have the top of the cylinder block milled off 0.010" and the head surface milled flat to match.

Mmmm. I have a Vesrah set in my stash. Will send a pm. Thanks!

[Progas]

I have used the MLS head gaskets for years on multiple builds and never had any kind of problems. It's really nice not to have to re-torque them with all the work involved.

[MRieck]

http://www.cyclexchange.net/Engine%20Parts%20(Non-Cafe-Gaskets).htm

I’ve read all the CyclEX gasket info and I am going to order a set for the top end of my current project. Their detailed descriptions of their product and attention to providing high quality seems apparent. Has anyone else used these products with good results?

I have used MLS head gaskets in a number of engines with no problems. The cylinder should be decked and the head milled AND the the finish must be flat and smooth. Some people deck and mill by dragging the parts down a sidewalk. You must use the heavy duty cylinder studs and torgue them to 23 or 24lbs. I use a very, very small amount of 1194 applied with a model brush around the oil feed and return holes.
 All modern bikes use MLS head gaskets and they have to stand up to liquid cooling as well.....there must be something to them.

[PeWe]

My K2 with later cylinder with larger  8 return holes got a head gasket from a Vesrah gasket kit.
It was rather hard fiber gasket. It did not compress.
It got the 8 higher o-rings and special dowel pins as original.

Retorqued day after. Tested all nuts by tighten with same torque as the day before. No movements.
Retorqued one by one,  release 1/2 turn followed by same tourque as the day before. Think it got 21.7 ft lbs (28Nm) APE cyl studs.
I have not used the bike that much after. No oil leaks.

Heavy duty cyl studs are thicker so I have drilled the oil transport holes in head bigger when stud block flow. Stock stud is 6mm there, Heavy duty studs 8mm. Some heads only 8.5mm holes.

I drill at least with a 9mm drill,  think I did 9.5mm in oil feed head holes, 9.0 on all the other. Oil return need flow too.
Heads holes are close to 9 mm.
I had a head where holes became really tight when alu was sunken and collapsed around holes. Brutal force to lift head off the married cyl studs.  Drilled all holes, shop milled all sunken areas for flatness and 90* relative holes.


I use the 2 o-rings for oil transport whith MLS.
Last times 0.76mm (0.030")
thick MLS so stock thickness O-rings OK. Cylinder had stock depth for those o-rings ca 0.95-1.0mm.

Dynoman has MLS head gasket in stock size 0.030" thickness to get better compression. Honda old stock gaskets were 0.8mm according to Hondaman.
http://www.dynoman.net/bikepages/sohc/gaskets-head.html

Important to check if gasket can handle the later cylinder with wider return holes.

RCS base gasket can increase compression a little more when using the thinner, 0.010". Stock fiber double thickness.
Possible to reuse, use a very thin film of high temp silicone on the outer sides where in contact with case and cylinder.

Wurth Super RTV or similar. I used a  black 329*C in a tube.
I let it dry 2-3 hours before assembly. No overflown dots near the oil holes
No leaks despite 2 dyno visits with multiple WOT runs up to 9500rpm and 3645km road.
That gasket was a leaker at base before. It has been reused several times.