Scan 'em if you got 'em - VF500F Head Gasket Patterns

FYI - The 85/86 front is marked RM

 

5x5, 'M' for the '85 and '86, 'J' for the '84.

As next step - gathering up some photos detailing the differences in the coolant passages**.

Here is a photo of an '86 pair of heads* taken from a previous post on VFRWorld...

*Gaskets have not been removed

**The coolant passages in the heads look to be the same on all model years - the difference is in the individual gasket design - based on the model year.

 

I can help out on this one, when I get to the shop tomorrow. I'll try to remember.

 

Those heads have the gaskets on them, so all you are getting is another view of the gasket.

 

Well noted. Thanks.

 

I've updated a few of the previous posts.

From what I can gather - the coolant passages for all three years have the same pattern (per photos in my Service Manual and previous post by Michael E).

The gasket designs are used to shunt off certain coolant passages - with the '84 having more passages open.

VF500F Gasket Round-Up

'84 Early Front - 12251-MJ8-405
'84 Late Front, '85 Front , '86 Front - 12251-MJ8-306
'84 Early and Late Rear - 12252-MJ8-405
'85 Rear, '86 Rear - 12252-MJ8-406

The next couple questions on my clipboard: can the gasket designs be used interchangeably, is there an evolution in the design and what does changing the flow of coolant do i.e. what would this affect, i.e. carburetor design/jetting, combustion efficiency?

Any thoughts would be most appreciated!

 

My thoughts:

Look at the shunted passages relative to the coolant piping on the picture of the head on the right. Note also that the round hole at the intake side of the head is smaller 84 relative to the evolved gasket.

It looks to me that the result would be more coolant forced across the head to (or from..I can't remember the flow direction) the exhaust side. I assume that Honda determined that the exhaust side wasn't cooling efficiently relative to the intake side. This assumption makes some sense when you look at the coolant passage design on the head (see post #17) which has little flow on the intake side relative to the exhaust.

Note also that the flow is diagonal across the head in the same direction on BOTH cylinders with the shunting, so it is not an issue of inner cylinder heat mitigation.

 

These fellas right?

 

I can't do it from here, but you can draw flow lines on the right hand head indicating the flow pattern across the cylinder from each of the two coolant tubes on the upper left of each cylinder to the bottom right of each.

 

Here's a page out of the service manual - Honda made some great drawings back in the day - showing the water hose pipes:

 

Side note to the research on head gaskets for the VF500F.

I recently wrote to Dave Dodge regarding copper gaskets. I had read that he doesn't recommend using them and wanted to know a bit more about why this is.

Dave writes:

The stock head gasket is fiber with a wire mesh, coated with a softer sealing material and a adhesive the bond to the surfaces. A copper gasket is more hard and without some kind of sealing material on it tends to not seal the water jackets. On old air cooled bikes we would aneal the copper gasket, and apply silicon seal to seal it. The water jacket typically requires a softer fiber material to seal. Newer bikes use a multi-layer spring steel gasket, coated with a thin black sealer. I have looked into doing some gaskets this way, but the prices are alot higher doing small runs than copper.

Good info to know!

With this in mind, Vesrah seems to be the best aftermarket option ('85 & '86 patterns are available) for VF500F owners.

 

Copper gaskets are made from a very soft type of copper. While I've heard that some people have seen problems with sealing, others have not. I suspect that it depends on several factors - not all of them being the gasket material. The next 500 engine that I build will almost certainly have copper head gaskets. Just to be safe, I'll probably put silicone sealer around the cooling jacket holes. Better to be safe than sorry!

 

As readers know, my copper gasket(s) failed. I used the sealant on both sides of the gasket as per the instructions, torqued everything down and pulled the head covers off after a few rides and checked the torque again (good).

The only thing that I can think of that might have helped was to machine the mating surfaces. I did ensure that there was no gasket material there and it felt smooth, but perhaps machining would have made for better sealing. I don't know if that would even be possible without splitting the cases and dropping everything.

When I was assembling the heads I was really worried about how small of a mating surface there is at the cylinder wall. It's only 1/4 inch or so. The OEM type gaskets appear to have a compressable copper ring at this spot so I would guess that it has better sealing properties due to its compressibility?

I could anneal the copper gasket and try again, but I am selling the bike and want to make sure the next owner will be ok. Yes, I care, lol.

I am interested to see where I had the failure. I hope to have the motor out and to start taking it apart again over the next few days.

 

Thanks Michael.

I did remember reading that your copper head gasket(s) failed and that you had a coolant leak.

Please keep us posted (pls take plenty of photos) on what you find out.

 

Pulled my heads tonight and I will post pictures in the next few days. As I suspected there was copper gasket blow-by past the cylinder wall into the coolant passages in several places. Also of note was that the thin layer of Permatex grey was completely compressed off of all of the mating surfaces and squeezed into the coolant passages. This resulted in several clogged or restricted coolant passage ports at the gasket. The sealant is recommended in the directions and I used the specified type. So, my overheating problem was a result of both heated coolant from the blow-by and of reduced/improper coolant flow.

My verdict for copper gaskets for THIS VF500 application is that they are a risky bet. I went this route to save money versus buying a full kit, but in the end it is costing my more. Copper Gaskets Unlimited is a good place to do business. They were good to me when getting the gaskets made to my sample. I would recommend them if your application calls for copper gaskets. Not for this bike though.

 

Thank you for the post.

From what you have found, this confirms what Dave Dodge wrote - copper head gaskets are a no go for the VF500F.

I look forward to seeing the photos.

 

Thanks for keeping us updated. I would agree that it seems copper head gaskets are a touchy item. I would still like to give it a shot, but your experiences will certainly give me something to look out for.

 

Here are some pictures of the mess described in post 75 above.

 

Here are some pictures of the Athena gasket set from Parts-n-more, $79. The quality is good and I am happy with them. Apparently Athena is an OEM supplier for some makes. If I had seen this set earlier I would have gone with it rather than copper.

Note that the head gaskets are both the same. To use it on the front you simply flip it so that the flow is right (described in posts above) and cut off the corner bypass gas port that is not needed on the front. Easy.

Note also that these head gaskets are the early 1984 design without the evolved coolant passage design. I will let you know how everything works in a few days.

 

Great posts Michael!

Thank you for adding the photos of the copper head gaskets and the photos and intel on the Athena set to this thread.

Look forward to seeing how everything comes together.