Oil Leaks - 1978 XS Special

Well, yes and no, it depends on where you start your experience with them, The early XS1650 had 53 HP at 7000 rpm, but they didn't "feel like it"
At least mine didn't, in fact it was a bit doggy feeling on the bottom end, it was quicker once the rpm's were up there, then the motor dropped to 48hp
through the 74, then bumped back up again., to 48 AT 6000 RPM, with that and the tire change it was a more robust acceleration to get to the top end.
My 650 has as much or more HP than my 2008 Suzuki Boulevard 800, at least as much. The CT50 may be a more comfortable ride but the 650 owns my heart! I will never be without one until I hit my last stop in the big Poker run in the sky...
 
  1. XS650 Enthusiast
    I am also having oil coming out of my exhaust manifold. It only seems to be doing it when the engine warms up. The bike sat for 5 years before I got it. I had it out for a ride for about 45mins and it was running great and then it just started leaking oil pretty bad from the exhaust manifold and I also have oil leaking out onto the top of the sparkplug from the cover above it. I don't know what to do, please help.

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  2. Today at 8:47 AM

    AlInFlXS650 New Member
    Above the spark plug would be the cam seal.

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  3. Today at 8:59 AM

    Hntg4evrXS650 Enthusiast
    It looks like it's coming out the little pipe looking tube under the cover. The seal around it is still good.

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  4. Today at 10:27 AM

    AlInFlXS650 New Member
    Other places it could be coming from in that area are the cylinder head cover, sealing washers on the head or I suppose it could leak out from the inspection cover or sealing washers and run along the engine to drip into the spark plug area but those would be obvious. More likely it is the cam seal and/or o-ring.

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  5. 43 minutes ago

    Hntg4evrXS650 Enthusiast
    It's coming out of the cover right above the spark plug. It's also leaking out the exhaust manifold where it goes into the head. Is there anything that I can spray in the engine to clean it? It looks like the valve stem seals are gunked up.

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  6. 9 minutes ago

    AlInFlXS650 New Member
    If that is the case and it was my engine, I would pull it and remove the top cover. I wouldn't trust riding a bike with a motor like that.

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I have two 650 Yamaha's with the same problem, head gasket leak, left side.
If I retorque the head bolts.
Is the proper procedure to remove one nut at a time apply antiseize to the thread apply a new washer and apply the correct torque? Also do you start with the #1 nut and then #2 and then #3 as in the tightening sequence?
 
If you're doing one at a time, I don't think it matters which one you do 1st or what order you go in. I'm in the process of doing this right now on a newly acquired 650. I started on one of the outer big acorn nuts and worked my way in (2 outer then 2 inner). I replaced the rubber/metal washers under the outer 2 acorn nuts with copper washers. I would pull one nut, clean it inside and the threads on the stud, anti-seize both, then re-install. I re-torqued in 3 steps (22, 25, 27 ft/lbs) on each nut I removed before going on to the next one. Last bolt done was the smaller one under the spark plug. That is part of the bolt pattern that holds the head on so it should be done if you're chasing a leak. It's torque value is less because it's smaller (16-18 ft/lbs).
 
I just retorqued a rebuild that was starting to leak and increased the torque on the large acorns from 27 to 30 ft. lbs, following the sequence laid out in the Haynes manual. Loosen one, torque it.
Having a TCI ignition, I'll pull the cam end covers off and pull the plugs to get a straight shot at the bolts next to the plugs.
If ya want to get real anal, loosen all the valve covers before torquing the head down.
That little 10mm head bolt below the carbs just gets snugged.

Leaks are gone for now.
 
I have two 650 Yamaha's with the same problem, head gasket leak, left side.
If I retorque the head bolts.
Is the proper procedure to remove one nut at a time apply antiseize to the thread apply a new washer and apply the correct torque? Also do you start with the #1 nut and then #2 and then #3 as in the tightening sequence?
prolly doesn't matter doing one at a time but I always start with the inner and work out. Doing the outside first just seems WRONG. LOL
 
I have noticed something recently when looking up torque values for bolts. Yamaha states that the head stud torque values should be set with the threads lubricated with oil. I have been using a molylube and others talk about using copper grease. It seems that molylube is the worst choice because I run the risk of stretching/breaking the studs. Copper grease is not particularly good either. Next time I pull the engine apart off comes the molylube and on goes the 20W-50.

Recent references I have seen:
http://www.nibtorque.com/sitebuildercontent/sitebuilderfiles/generaltorqueguide.pdf
http://www.nibtorque.com/sitebuildercontent/sitebuilderfiles/40percentyieldwwwnibtorquecom.jpg
 
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Methinks you worry too much, LOL.
Then I looked at the charts. Those are for a whole nother class of bolts, the diameters strart at 3/4", go up to 3-4". Metal to metal surface area is oceans larger on those compared to the 8mm head studs on an XS650. I see round number 15 to 25% reductions in torque for various lubes on bolts down in our size range. I'm sticking HaHa! with anti-seize
 
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I've been using anti-seize on pretty much all my fasteners for probably close to 40 years. I've never had any issues. I stay at or slightly below the given torque values. Has there been the occasional stripped or broken bolt? Well sure, but I think there were less of them because of the anti-seize, and none were ever head bolts. I never gave much thought to the often mentioned school of thought that torque values should be reduced for lubed fasteners, but I have started to now. Another just as important factor I'm considering is that most of these fasteners, along with the threaded holes they go into, are old and well used, and many go into alloy. So, the combination of lube and age has got me using less torque than I used to on some fasteners.

When it comes to the 650 head fasteners, I used to do the 30 ft/lbs for the 8 large acorn nuts, but I'm getting away from that. It had worked in the past for me, curing the leaks on my 650 when I first got it. I used it again when I did my topend rebuild but after 8 or 9 years, that head gasket began giving out. So, even though I always kept them tight, the extra torque didn't seem to help much. I'm wondering if all I've done is just put more strain on the studs and components.

Another thought that occurred to me is the big difference in torque values between the 8 acorn nuts and the 2 smaller M8 bolts on the left and right outer edges under the spark plugs. Could this be warping the head, or possibly just those left and right outer edges? Searching spec listings, most put them at 14 to 16, but one did list them at up to 18. So that's what I do now, those outside bolts at 18, the 8 big acorn nuts at about 27. Still not equal by any means, but closer than 16 and 30.
 
I've been using anti-seize on pretty much all my fasteners for probably close to 40 years. I've never had any issues. I stay at or slightly below the given torque values. Has there been the occasional stripped or broken bolt? Well sure, but I think there were less of them because of the anti-seize, and none were ever head bolts. I never gave much thought to the often mentioned school of thought that torque values should be reduced for lubed fasteners, but I have started to now. Another just as important factor I'm considering is that most of these fasteners, along with the threaded holes they go into, are old and well used, and many go into alloy. So, the combination of lube and age has got me using less torque than I used to on some fasteners.

When it comes to the 650 head fasteners, I used to do the 30 ft/lbs for the 8 large acorn nuts, but I'm getting away from that. It had worked in the past for me, curing the leaks on my 650 when I first got it. I used it again when I did my topend rebuild but after 8 or 9 years, that head gasket began giving out. So, even though I always kept them tight, the extra torque didn't seem to help much. I'm wondering if all I've done is just put more strain on the studs and components.

Another thought that occurred to me is the big difference in torque values between the 8 acorn nuts and the 2 smaller M8 bolts on the left and right outer edges under the spark plugs. Could this be warping the head, or possibly just those left and right outer edges? Searching spec listings, most put them at 14 to 16, but one did list them at up to 18. So that's what I do now, those outside bolts at 18, the 8 big acorn nuts at about 27. Still not equal by any means, but closer than 16 and 30.
I'm glad I came upon this. I'm about to install the 750 kit, getting prepared and syked, getting things laid out for tomorrow. Suddenly, it dawned on me. What are all these O-rings for in the Mike's (Athena), 650 gasket kit? Yes, the little red one for the crank halves and the 2 big red ones for the points and advance covers and the O-rings for the late model valve covers. Don't need the biggest o-rings for the base of the 750 cylinders.
So what are all those other O-rings for? Am I missing something? Paranoia is setting in. And my 71 Yamaha manual is vague at best. Please, all may chime in. Thanks in advance!
 
There are 4 o-rings for the valve guides, which you won't use if you didn't pull the guides out (most of us don't). There are 4 o-rings for the sleeves that fit into the top cover in the 4 outside stud holes. Again, if you didn't remove those, you wouldn't use the o-rings. They only need to be removed if you're going to pull the rocker shafts out. There are 4 o-rings for the rocker shaft end caps, no need to replace those either if yours aren't leaking (just keep them for spares). I didn't think the Athena gasket set included valve cover o-rings.
 
Ok, almost there. A little history. When I bought the 75, for the crank only, it came with an additional rebuilt head. The rockers and bearings appear to be the best of 3 heads, but some things were missing, as in the 1st pict, those sleeves. That covers the 4 red o-rings. There were no chrome Phillips rocker nuts, so that covers the 4 black o-rings. Any idea where those 2 larger so-rings go?
 

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And what about the gaskets/washers that go behind the chrome things that hold the front cam chain guide? I'm using a copper washer right now. Any suggestions?
No, your right, no valve cover o-rings with this set.

Off subject, bought the Pamco w/built-in advance. Got any good coil mountings.

Oh, and thanks for the new torque settings. And the anti-seize is an excellent idea.
 
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The 2 larger o-rings are for behind the points/advance housings. The originals were red and I think they were better. I used the black ones from the Athena kit on mine and when I had occasion to remove those housings a few years later, I found them all deformed. I re-assembled them using old original (still good and not deformed) red o-rings.

Yes, the front cam chain mounts get copper washers. I always just reuse the originals. Usually I only remove the bolts that hold the guide, I don't disturb those chrome nuts they fit through. No need to in my mind. I usually also don't disturb the breather housing on the back of the head. Again, I see no reason to remove it. The only reason I can see for removing these items would be if they leaked oil and you needed to fix that. Most do not so I don't disturb them.
 
Interesting. I found on both the 72 and 75, that each had one deformed red o-ring behind the housings.
As for the chrome nuts, there was a thick paper washer like the one under the neutral light sending unit. Both of which were on tighter than week old goose shit on the bottom of my hiking boots. I'll try a copper washer on the sending unit. If it leaks, it's easy to replace. All the other things you mentioned, I have to put on since the head cover was bare except for the rockers.

Interesting note, the little spring steel breather blocker was not in the 72 head. And this is the 1st time it's been apart. I'll use the one from the 75 along with the dipstick. Maybe I'll blow less oil out this year.

Any ideas on the coil mount?
 
The coil mounting will obviously depend on the coil you use. Very few, if any, match up to the original mounting points so some sort of adapter bracket will need to be fabbed up. I run a Harley style coil. It's aftermarket but made in the same shape and size as the stock Harley coil it replaces. It has little threaded studs on each end for the wire connections, to which I added bolt-on spade terminals. Then I made up short jumper wires with bullet connectors so it would plug into my harness .....

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I made up a sheet metal adapter bracket to mount the coil. It rolls the coil into the center of the frame and also includes a tab for the turn signal flasher. That needed to be moved slightly to allow coil clearance .....

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Basically, you'll have to wait until you have the coil in hand to figure out exactly what you need to do for mounting. But, on the early 2 coil mount frames, a bracket similar to mine that rolls the coil into the center works well.
 
Great bracket. I like the tilt. I bought the black coil from Mike's. Just tempied it on with stiff foam pipe insulation and cable ties. You have inspired me. Thanks.
Well, The old 72 is running again. Put about 60 miles on it. AND NO LEAKS! Thanks to all you guys. Oh, I used the 75 clutch and it has a more solid feel to it. In case I forgot to mention it, I installed the Mike's 750 kit. It has gobs of torque now. 5th gear just keeps on pulling. I also ported and polished it. Followed "Porting for extreme power," from the garage. Used anti-seize and retorqued the head several times, thanks again. My only challenge is the compression. It's really hard to kick over now. Luckily I still have the compression release starter.
 
Sounds cool Marlin. Is your timing spot on? I don't find 750 motors all THAT bad if the timing isn't advanced.
 
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