Topic: What’s the Very Best cb750 Gasket Set?

[BenelliSEI]

I’m getting ready to work on a very early cb750 engine (#581). I had it running well a few months ago, after sitting dormant for +40 years. No chain noises, smoke or surprises. Shows 17,000 miles on the speedo and I believe that to be correct. It does have a minor head gasket leak, and a few bent fins of the RHS. I plan to do only the top end.

What gasket sets have you used and consider the best? Did you need to retorque the head gasket after first use? Athena top end kits available locally, and I like the look of sets listed by Cyclex. What do you recommend? Thanks!

[jaytee-nz]

I've used the Yamiya head gaskets several times and never had a problem (Japanese quality).
They also state that the gaskets are the thickness of the original Honda ones so shouldn't have the o ring issue many others have. Never had to re-torque the head also.
I believe Athena also have a good reputation (seem to recall that Hondaman uses them so that's a recommendation).

[ekpent]

 Be nice if it was just the rubber pucks that were causing the leak and you didn't have to remove the head and cylinders and take it down that far.

[BenelliSEI]

Be nice if it was just the rubber pucks that were causing the leak and you didn't have to remove the head and cylinders and take it down that far.

The engine S up in the stand and getting a really good scrape and clean up. Will be checking carefully. There is a lot of muck in a couple of spots. I suspect more than the pucks. We’ll see.

[ekpent]

 With your mechanical ability and the engine all set up probably a good idea to go for a one and done. My hand would probably be shaking a bit working on a Sandie bike with that low of a number.    Hopefully no special head gasket or such for one that early.

[MauiK3]

I used Yamiya gaskets. I rechecked torque the next day just to be sure.
#581 is sure low, keep us posted.

[71 V12]

I would recommend opening the sump as well whilst the engine is out. Found a little house of horror lurking in my K0, primary tensioner and cam chain rubber parts were all breaking up. You can see the bits on the oil pump mesh, loads more in the sump pan.

Engine sounded great before pulling it, and was oil tight. The only work I intended to do was give a clean and paint. Ended up with a full rebuild and so glad I did.

For what it worth I used genuine Honda gaskets and seals.

[BenelliSEI]

I would recommend opening the sump as well whilst the engine is out. Found a little house of horror lurking in my K0, primary tensioner and cam chain rubber parts were all breaking up. You can see the bits on the oil pump mesh, loads more in the sump pan.

Engine sounded great before pulling it, and was oil tight. The only work I intended to do was give a clean and paint. Ended up with a full rebuild and so glad I did.

For what it worth I used genuine Honda gaskets and seals.

Excellent advice. I will definitely be going in there and I happen to have an NOS primary tensioner in my spares......

[PeWe]

I also like the Yamiya's gaskets. Good fitment and cover gaskets like Honda.
Many other gasket sets has bad fitting with holes not lining up and a rough paper like surface.
Not the waxed feeling as Yamiya (blue) and Honda (light green)

Measure the primary chain slack when oil pan is off. Probably not much more than new chains 65mm. Low milage. (Service limit 70mm)

It would be fine if the rubber tensioners could be replaced without tearing everything apart, primary as cam chain.

I found more rubber from tensioners in oil pan when I opened my K6 2010.
Last time tensioners were replaced was 1984.

[Remcod]

If you use the cyclex ones, remember to shorten the breather cover bolts. They are too long because the gaskets are a lot thinner and will snap if you think you can force them down because you didn't realise this. Don't ask how I know this.

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[Shtonecb500]

Vesrah is used in our shop.

[flybackwards]

I used the Cyclex dual layer steel head gasket and their other gaskets on my K7 rebuild - all tight for oil but it looks like the head gasket needs to be re-torqued - I started to get a few seconds of oil smoke on startup from #1 after I did a hot run on 401 for a couple of exits. Most likely I was light on the torque at assembly. All the Cyclex gaskets look like good quality.

[atm cycles]

Be mindful that a couple gaskets are unique to Sandcast only. Oil pan and clutch cover. The head gasket is also different from early diecast back. I suggest using a nos with the copper rings. As recommended by MRieck

[BenelliSEI]

Tons of excellent advice. Much appreciated!