After researching for more than an hour I have given up. Do I use sealer on my versah gaskets for the top end or not? Which sealer? and where do I apply it? This is my first rebuild and I have no experience with any of the sealers. There seems to be a bunch of different opinions on this topic so everybody with non leaking bikes speak up please.
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From what I have gathered its a hot topic. Im not going to chime in on it really, other than this last time I re-did a lot of the oil gaskets on both bikes, I did not use any sealant or glue. All was applied dry, or used some silicon just to keep the gasket on the removable part, just a small dab. Both of these bikes are still apart, so I can not claim to have any input on how the dry run went. All were torqued to spec, and left.
As far as the headgasket, or main jugs, Id wait for GGGary, 5twins, XSLeo, or a few of the other veterans of the board to chime in. What ever you decided to do, let us know how it turns out.
As far as the headgasket, or main jugs, Id wait for GGGary, 5twins, XSLeo, or a few of the other veterans of the board to chime in. What ever you decided to do, let us know how it turns out.
For the engine case to the cylinders, just install the gasket, no sealant.
For the cylinder head gasket, use a thin bead of Three Bond 1104 around the camchain tunnel and around each of the 4 outer stud holes. Apply to both sides of the gasket.
For the valve cover, no gasket is used, just use Three Bond 1104.
Cleanliness is super important. Use something like lacquer thinner to clean the surfaces just before assembly.
Make sure the camshaft bearings are pushed fully inwards (with the camshaft centred). You want to have equal amount of camshaft showing at each end. This is so that the oil seals will fit properly when the camshaft end covers are installed.
Torquing also super important. Use 30 ft-lbs for the 8 large 10 mm studs, 14 ft-lbs for the 4 8 mm bolts and the 2 under the spark plugs, 7 ft-lbs for the 1 bolt at the back centre. Re-torque several times after some miles are put on (leave the top engine mount off).
Yeah, the good stuff here is buried deep. Try diving thru this, and follow RetiredGentleman's links:
http://www.xs650.com/forum/showthread.php?t=7500
chizler62
XS650 Addict
If the cases are a machined fit, no gasket, HondaBond4 or Threebond 1104.
If it has a gasket it doesn't require, shouldn't, sealer. Unless you're using a dab to align the gasket.
If it leaks with a gasket.
1 gasket is poor quality
2 surfaces weren't clean
3 heat distorted part. Human error typically
4 God doesn't like you @
Posted via Mobile
If it has a gasket it doesn't require, shouldn't, sealer. Unless you're using a dab to align the gasket.
If it leaks with a gasket.
1 gasket is poor quality
2 surfaces weren't clean
3 heat distorted part. Human error typically
4 God doesn't like you @
Posted via Mobile
Yes, most of us use a little sealer with our aftermarket head gaskets. Yamaha did the same on theirs. If you look at a factory head gasket, you'll notice the areas at both ends of the cam chain tunnel shine. This is factory applied sealer .....
We expand upon this a little, adding rings of sealer around the 4 outside stud holes because they flow oil, and we totally ring the cam chain tunnel. I also like to string a bead between the outer stud hole and the tunnel along the front as this seems to be a very leak-prone area .....
I've revised my sealer application slightly recently. Instead of placing it on the gasket I now put it directly on the head and cylinder. Why? Well, from studying the cam chain tunnel cut-out in the head and cylinder, the one in the head is larger. It would be possible to miss the sealing surface completely in spots if the sealer were applied on the gasket too close to the tunnel cut-out .....
There's also the matter of that groove cut into the sealing surface nearly all the way around, near it's outer edge. My best guess is that allows the gasket to form a ridge or "dike" around the perimeter, helping to hold in compression and oil. Getting it full of sealer probably isn't a good idea and can be better avoided by applying the sealer directly to the hard parts .....
We expand upon this a little, adding rings of sealer around the 4 outside stud holes because they flow oil, and we totally ring the cam chain tunnel. I also like to string a bead between the outer stud hole and the tunnel along the front as this seems to be a very leak-prone area .....
I've revised my sealer application slightly recently. Instead of placing it on the gasket I now put it directly on the head and cylinder. Why? Well, from studying the cam chain tunnel cut-out in the head and cylinder, the one in the head is larger. It would be possible to miss the sealing surface completely in spots if the sealer were applied on the gasket too close to the tunnel cut-out .....
There's also the matter of that groove cut into the sealing surface nearly all the way around, near it's outer edge. My best guess is that allows the gasket to form a ridge or "dike" around the perimeter, helping to hold in compression and oil. Getting it full of sealer probably isn't a good idea and can be better avoided by applying the sealer directly to the hard parts .....
EvenmoreXS
1981 XS650
" For the engine case to the cylinders, just install the gasket, no sealant.
For the cylinder head gasket, use a thin bead of Three Bond 1104 around the camchain tunnel and around each of the 4 outer stud holes. Apply to both sides of the gasket.
For the valve cover, no gasket is used, just use Three Bond 1104.
Cleanliness is super important. Use something like lacquer thinner to clean the surfaces just before assembly. "
I've done it this way with complete success. Follow 5twins advice...It was his advice, among others, that I followed originally.
For the cylinder head gasket, use a thin bead of Three Bond 1104 around the camchain tunnel and around each of the 4 outer stud holes. Apply to both sides of the gasket.
For the valve cover, no gasket is used, just use Three Bond 1104.
Cleanliness is super important. Use something like lacquer thinner to clean the surfaces just before assembly. "
I've done it this way with complete success. Follow 5twins advice...It was his advice, among others, that I followed originally.
chizler62
XS650 Addict
If you're using sealer on the head gasket and the OEM gasket doesn't require it. You're damaging the head itself and masking the true problem. Whether it be surface finish, gasket quality or fastener torqueing. Improper fastener torqueing is the #1 cause in the motorcycle industry for head gasket area failures.
-The head's surface has a specification on roughness. It's call (RA) roughness average measured in microinches. You use a Profilometer to measure this.
- The gasket, typically cheap gaskets are of common material and are not at specification either(yeah, you really didn't save $10 for no reason). Use a durometer on a NEW UNUSED OEM gasket that hasn't been on a shelf exposed to UV for ten years and measure the aftermarket one. You'll see a difference.
-So, Those "sealer on the stock" gasket areas you're noticing. They are there because of Gasket compression limits are required to be different in certain areas of the surface. This is how they achieve that. When you add more sealer you're actually over tightening the fasteners, over compressing the gasket crushing cells within the material. This begins creating small valleys and pockets that warp the head.
Well, What do we do if you've already done this and or have a head that surface, flatness and finish isn't in spec?
YOU REALIGN THE HEAD. Yes, realign the head.
I have a 2" thick steel plate that is .0005" true. I shim the head on the plate until the CAM JOURNALS are perfectly parallel to the plate not the head surface. I clamp it down firmly. Put it in the powder coating oven for the DAY at 400-450. This will slowly draw those valleys and pockets back flat against the plate.
Refinish the heads surface to 20-30 microinches and you're done.
-The head's surface has a specification on roughness. It's call (RA) roughness average measured in microinches. You use a Profilometer to measure this.
- The gasket, typically cheap gaskets are of common material and are not at specification either(yeah, you really didn't save $10 for no reason). Use a durometer on a NEW UNUSED OEM gasket that hasn't been on a shelf exposed to UV for ten years and measure the aftermarket one. You'll see a difference.
-So, Those "sealer on the stock" gasket areas you're noticing. They are there because of Gasket compression limits are required to be different in certain areas of the surface. This is how they achieve that. When you add more sealer you're actually over tightening the fasteners, over compressing the gasket crushing cells within the material. This begins creating small valleys and pockets that warp the head.
Well, What do we do if you've already done this and or have a head that surface, flatness and finish isn't in spec?
YOU REALIGN THE HEAD. Yes, realign the head.
I have a 2" thick steel plate that is .0005" true. I shim the head on the plate until the CAM JOURNALS are perfectly parallel to the plate not the head surface. I clamp it down firmly. Put it in the powder coating oven for the DAY at 400-450. This will slowly draw those valleys and pockets back flat against the plate.
Refinish the heads surface to 20-30 microinches and you're done.
Brew, I'm not challenging any of the advice you've been given, but the more you get into these motors, the more you'll realize two things: First, there's more than one way to skin a cat. Second, this ain't rocket science, and reinstalling your head with a good seal doesn't require a machine shop and five figures in gear.
I've seen more than one case where a professional has assembled one of these motors without dressing the head gasket a bit and had oil leaking into the combustion chambers from the cam chain tunnel. My personal practice is to spray the whole surface of the head gasket with 3 coats of Permatex copper gasket spray. I use the same stuff on the base gasket except if there's a little roughness on the surfaces of the case and/or cylinders; if so I use Permatex Ultra Black. Theory is all very nice, but when I do motors this way, they don't leak.
BTW, I've never seen a warped head on an XS650, but I've seen badly warped rocker boxes, and those can't be milled flat. chizler, your recipe is the only one I've seen for recovering a tweaked rocker box; thanks!
I've seen more than one case where a professional has assembled one of these motors without dressing the head gasket a bit and had oil leaking into the combustion chambers from the cam chain tunnel. My personal practice is to spray the whole surface of the head gasket with 3 coats of Permatex copper gasket spray. I use the same stuff on the base gasket except if there's a little roughness on the surfaces of the case and/or cylinders; if so I use Permatex Ultra Black. Theory is all very nice, but when I do motors this way, they don't leak.
BTW, I've never seen a warped head on an XS650, but I've seen badly warped rocker boxes, and those can't be milled flat. chizler, your recipe is the only one I've seen for recovering a tweaked rocker box; thanks!
