How to: head gasket replacement

Guys & Gals,

I just bought an 85 VF500 knowing the head-gasket is blown. I am not mechanically inclined but I want to try this repair. I have a neighbor that is slightly more inclined than I and he is willing to help.

The question is (and I have searched but not found anything) what are the high level steps (and any gotchas) that I need to complete in order to replace both head gaskets?

Also what is the name of the business that sells the after market gaskets for this bike?

I would really appreciate the assistance.

Sean

 

first off, i wouldnt hold your breath on the availability of an owner-written howto on something like a head gasket...thats a pretty involved job to be documenting every step of the way. your best chance is to locate a factory service manual for the bike, which will actually have something close to a howto for...well....everything. im sure theres one out there for your bike, its just a matter of hunting the right one down.

second, i dont know about aftermarket head gaskets, but i know the honda gaskets are easily available. just go to Service Honda Home of the CR500AF 500AF 500AFX Junior-X - Honda Motorcycle Parts and you should find pretty much everything you need.

third, remember that youre about to tear into a 25 year old engine, having no idea of the condition of the motor, nor its past service history. do yourself a huge favor and read thru the service manual before you buy the parts, and replace every seal and gasket that you remove from that bike with a brand new one. i never re-use stuff like that, and youll only shoot yourself in the foot by doing so. and you might wanna go ahead and replace the carb boots while youre at it, cause they tend to not last (and they may just fall apart when you remove them anyways)

 

Sounds like a nice project.The manual has spec's and info ala Honda,enjoy the experience no matter what

 

in progress...

Amongst other things I've already done that I need to do in order to remove the motor - I am in the middle of removing the exhaust: got the header pipes and cans off. I am trying to locate the nut and washer that holds the main collection area to the oil pan. Does anyone know where this is? :unsure:

This is quite the time consuming repair!

Also - I will need to order a replacement head gasket (front and rear). There is a company mentioned on this forum that makes them: (Copper something?) but they list them by cylinder count (obviously 4) and some other number like (.013, .021, etc). What are these numbers and which one will I need to order?

Thanks!

Sean

 

I bought a factory Honda service manual on Ebay and it has been very useful (you might have that already).

Not sure if the site OldBikeBarn has what you need for gaskets. I have been eying a top end gasket set on there, but have never bought anything from them yet.

Take digital photos of where the wires and tubing run (I point at each spot that might look tricky).

that is my 2 cents.

John M

 

You might send a PM to "masonv45". He is very helpful on subjects like this.

 

i get most parts like that from servicehonda.com or from powersportspro.com. i think servicehonda is a little cheaper, but both should have what you need. as for the numbers youre seeing, those look like gasket thickness. if you have choices, id consult the service manual to learn what the stock thickness is/was, as a thicker gasket could cause you to lose a little bit of compression, and i dont know that a thicker head gasket than stock would give you any benefit.

 

Hassall; First of all why do you feel the need to use other than stock Honda head gaskets? The .013,.022 refers to head gasket thickness,not sure the thickness of the stock Honda head gasket. Different thickness head gaskets are made so that you can adjust (SLIGHTLY) the compression ratio of youe engine. I would stay away from the thinner head gasket because they have more tendency to leak and or blow. Also you really should consider letting a pro or a shop do this work. Now if you are just playing with this machine and dont really have any plans to ever ride it, then have at it. If you want to change a head gasket go change the one on your lawn mower or snow blower,but for the sake of the machine leave this fairly complex engine to some one with experience! eddie

 

Thanks everyone for your responses. I downloaded the manual off this site (a wonderful thing) and the engine is now free of all the metal and wires that make it a motorcycle. It's sitting pretty on a furniture dolly waiting for me to remove the heads. I will be ordering the head gaskets in the next week or so (pending my accountants approval :frown:

Any tips (other than involving a professional or shop) would be greatly appreciated. I want to do the work myself and learn in the process. Unless it involves milling or machining - I want to do it myself. :strong:

Anyway - thanks again everyone!

Sean

 

Have at it. That's the only way to learn. Be careful not to drop anything in the engine. Other wise you'll be pulling the pan. Make sure all parts go back where they started because they are mated. ex: cam caps and gears. Take your time and read about doing what ever your doing first a couple of times, then do it. Clean all head bolts in kerosene or cleaner then oil them before installing and torque to it's value and pattern. Use very little silicone! Some guys goober it on were needed and it squishes out in to the engine and creates problem later if it breaks off. It's better to use an anaerobic type sealer when needed or some guys like Yamabond. Clean, clean, clean everything!! Most parts will need a coat of oil on them when installing. Oh yea get a box of swear words, you'll need em!:biggrin:

You can get OEM gaskets/part from cheapcycleparts.com at the lowest prices I've seen.

 

Dear Hassall; I dont know if it was mentioned before but make sure that you have a good
metric torque wrench,it is especially important when tightening down the
head bolts. Sounds as if you are bound and determined to do this job, I
hope the motorcycle fairies grant you good wishes! eddie

 

headgaskets don't blow for no reason. usual cause is overheating, so check cooling system, especially fan and thermoswitch and radiator. overheating can warp head, so you maybe should have it checked at automotive machine shop. you will need an accurate torque wrench to properly assemble motor top end. your biggest danger, i think, is not over-tightening fasteners threaded into aluminum alloy.......

use lots of oil on cams when assembling. crank engine without starting to build oil pressure before starting.

change oil and filter before starting engine first time.

as the Eddies stated, this is probably NOT a good job for rank amateurs to complete SUCESSFULLLY.

 

NO SILICONE is needed.

Probably the most important part is getting all the gasket off the block/head.

If the aluminum is not shiny, then it's not clean.

Measure the block/head and make sure it's not warped.

Wipe the block and head mating surfaces with alcohol to remove any residue.

The gasket will cover some holes - that's normal - just make sure you orient it correctly.

After buttoning everything down, run the bike without coolant until the engine is warm to the touch. This will help the glue impregnated in the gasket adhere to the block/head.

Fill with coolant and then start back up.

I have a method of refinishing the block/head surface that worked for me - but it's not recommended. PM me if you want to attempt it yourself.

 

It has been mentioned already, but be careful tightening the head bolts. Aluminum parts strip easily and a stripped head bolt is not fun(experience from the old beater Yami).

 

Before you spend too much money, make sure you can get the head gaskets. I just replaced my head gaskets (85 VF500F) a few months ago. Everywhere I looked, the rear head gasket was unavailable.

Fortunately, the front and rear gaskets are very similar. The rear has an extra portion to seal the breather. Other than that, they are exactly the same.

I had to mill an o-ring groove on the rear cylinder head and install a viton o-ring to seal the breather. It is very important to seal the breather, otherwise you will lose the crankcase vacuum needed to trigger the fuel petcock and reduce oil leaks around seals.

 

I just checked into it, and i cant find anything on servicehonda.com, as the website is acting kinda wonky, but both of your head gaskets for the 85 VF500 are available through powersportspro.com

 

I just looked up the rear head gaskets (85 VF500F) on powersportspro.com. This is what came up:


8 Loading... SKU: 12252-MJ8-010
GASKET, RR. CYLINDER HEAD (Honda Motorcycle Code 1845684) (NOT AVAILABLE) Use up to Engine SN 2105144 Use up to Engine SN 2105144 1 $23.86

8 Loading... SKU: 12252-MJ8-020
GASKET, RR. CYLINDER HEAD (Honda Motorcycle Code 2172112) (NOT AVAILABLE) 1 $23.86

Notice that both of the listings say (NOT AVAILABLE) in the description.

I was able to find a website (don't remember which one) that didn't say (NOT AVAILABLE) But, a few days after I ordered it they called to tell me that is wasn't available.

 

First of all - thanks to everyone for the replies - very informative.

Second - I can't find the rear anywhere! Surprised? Nah, I didn't think so. :mad2::mad2:

So, any advice on finding or having a gasket made? We could resolve this problem once and for all if we had one that wasn't used. We could send it to copper gaskets and they could take the accurate measurements. Then we could have them whenever we needed.

For all you seasoned mechanics out there - you will be happy to know I found someone to do the work at a very good price - all I have to do is drop off the motor. I will be dropping it off to have said work done as soon as I can find the gasket.:unsure:

Lately I feel like this guy :ncb:

 

Yeah, the head gaskets have been discontinued for a couple of years now. You should try CopperGaskets Unlimited Home Page , they can make the VF500 parts for you. The nice thing is that they can use your choice of material thickness so it's possible to bump up the compression. You can't get much because the stock VF500 gasket is pretty thin.

You might want to check the head surface for flatness too. That would be a good excuse to mill them down (that's where you can get some compression). I've had good luck doing this on the VF500 heads in the past. For best results you would want to degree in the cams afterwards, but it's not 100% necessary, especially for the street.

 

Jamie & Others,

I called this company (Copper Gaskets) and Lani called me back telling me that the measurements he had for the rear were incorrect. Someone had placed an order and called him back telling him that it didn't fit. Front was fine - rear ... not so much!

If we can get him the correct measurements - he will be happy to continue producing this part for us. Anyone have the correct measurements?

I looked in the Clymers and the Honda service guide and neither have the measurements. Honda customer service couldn't provide them for me either.

This is all for not if I can't source the damn rear head gasket. ope2:

Sean