1980 Engine Top End Rebuild

JTD1989

XS650 Enthusiast
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Los Angeles, California, USA
Hi everyone, I am new to participating in the forum, but I have had my XS for about 4 years and have done a lot of research and learning on many of the great threads on here. I have very little mechanical experience, but I am learning a lot in this process.

I bought the bike several years ago and it ran rough but looked pretty. The PO was not the one who built it and had very limited knowledge to pass along about its history. I rode it for awhile and had some problems, cleaned the carbs and they got better, then one day she died on me and I couldn't get her to start back up by checking all of the easy obvious things. The PO had mentioned that when the bike was chopped they had done some engine rebuilding so I decided the best thing to do would be to open up at least the top end and see how messed up the engine is internally.

I have disconnected everything, pulled the engine, and taken it apart down to the case so far and will attach some pictures of my findings in the next post.
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So I got the motor out
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And took off the head cover
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And I discovered some signs that something came loose at some point and was bouncing around in the space where the cam sits in between the cylinder head and head cover
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but whatever it is has apparently already been removed and the damage has been repaired.
 
My first question for the members of the forum is: is there some kind of secret for getting the locating dowels on the engine bolts out of the head/head cover? I haven't tried cranking on them with pliers or anything because I don't want to scratch them or get them out of round, but they seem to be stuck. I wanted to remove them to flatten the mating surfaces.
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Which brings me to my next question: Is it a bad idea to flatten the engine surfaces by using a flat surface with a thick piece of glass on top with fine sandpaper aerosol-adhesived to the surface? The manual says to use a surface plate, which I don't have, and 400 or 600 sandpaper wet in a figure 8 motion. I do have #600 wet/dry polishing sandpaper and a thick piece of glass. I already tried it on the top of the jugs and I was pretty happy with the results. I read from another source not specific to XS650 engines that it could be done starting with rougher grit (they said 60 grit) then moving to 120, 220 so I tried that with the jugs. After very lightly using the 60 there were scratches that seemed too deep so I moved up to the 220 and it seemed to do okay but I spent most of the time on the 600. For the other surfaces I was thinking of lightly doing the 220 then going to the 600 or maybe even just doing the 600. Thoughts?
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I also just wanted to confirm my identification of my electric components. Based on my research I believe that I have a Pamco ignition and a permanent magnet aftermarket alternator, right?
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is there some kind of secret for getting the locating dowels on the engine bolts out of the head/head cover?
I use a socket that's a snug fit inside the alignment bushings.... loose enough to remove easily, but big enough that it doesn't move around. Stick it in the bush, put an extension on it and rock it back and forth. Might take a minute, but it'll eventually rock it's way out.
Is it a bad idea to flatten the engine surfaces by using a flat surface with a thick piece of glass on top with fine sandpaper aerosol-adhesived to the surface?
Nope. That's how I do it... except I use a cast iron sawtop. 60G is crazy rough... :yikes: I've never gone coarser than 180g to start. I usually go 180, 220, 320 and finish off with 400. I use WD40 for a lubricant... very liberally and constantly change the direction I run it across the paper.
Yes that's a PMA alternator.
Looks like a Pamco iggy to me, but I've never actually seen one in person. :rolleyes:
 
I've never re-surfaced one of these, never saw the need to. Be careful on the head/cylinder joint. Remove too much and you're going to raise the compression which could result in a motor more prone to pinging. Since I never re-surfaced, I never removed the dowels, but I have found some quite loose and easy to just pull out by hand.

One of the things you're going to need to do is determine whether or not the cam chain was replaced on the last rebuild, and if not, how stretched out it is. Personally, I replace them on any motor with near 20K miles or more on it. They're usually pretty stretched out by then. They don't necessarily have to be but usually are due to lack of maintenance. They were never checked and adjusted frequently enough. One of the signs of a stretched chain is running out of adjustment on the timing plate. Your Pamco plate looks good, still in the middle of the adjustment range, so that could be a good sign. The chain may have been replaced and is still relatively new. One of the ways you may be able to tell is to locate the master link on the chain and inspect it's rivet job. The factory did a very crude job .....

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A competent builder probably did a much better and nicer looking job .....

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Thanks for the advice on the bushing Jim. I will give that a shot. And I will also skip the 60 grit from now on. I'm glad I started very gently and only did a few strokes.

5twins thanks for the cam chain advice. Based on reading your suggestion in other posts, I decided to go ahead and replace the chain. I was a little torn because it appears to be in good shape and the rivets on the master link are very neat, but I decided I would rather replace it now than have to tear it all back apart when I finally get it back together. There is no odo on this bike and who knows how well it has been maintained?

Once I get it together I just want to be able to ride this thing! It has been about 3 years since it was running. And I moved to Southern California from Ohio two years ago and haven't been able to ride a motorcycle this whole time!

So I purchased the endless chain and master link from Mikes. When it gets here and I have to break it do I just grind out one pin freeing one side of one link then grind out the pin on the other side of this half-free link to effectively remove one link from the endless chain? So you are basically removing one link and replacing it with the master link? This may be obvious, but I just want to make sure I have the right number of links.

Also, to do the timing with the aftermarket alternator is the best method the degree wheel?

Thanks
 
To check the chain for stretch, I would remove the cam chain tensioner (pull the adjuster screw with the spring and plunger right out) and see how loose the chain is. Is there enough slop in it to lift one side of the cam up say 1/4" or so? Can you pull the chain away from the cam sprocket on top by very much? I'd judge by how much "slop" you find on whether or not to replace the chain. If you decide to then yes, find the master link and grind off the riveted ends on both pins like so .....

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Then take a small pin punch and just tap the link out.
 
Once the head is off, you should be able to accurately find TDC by just looking at the pistons. Then mark your new alternator. It should have been done when it was installed but many don't. I don't know why (yes I do, they're idiots, lol) because without marks you can't check and set timing or valves.
 
So I purchased the endless chain and master link from Mikes.
You should really check Partzilla for parts before resorting to Mikes. Partzilla has an OEM chain and link for 45 bucks... less than the $50 Mikes wants for the aftermarket. I'll take OEM over aftermarket... especially when it's cheaper.
To remove chain link....

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Thanks for the tip about removing the chain and on Partzilla. I actually did check there and they were out of stock for the cam chain when I checked :(

As far as marking the alternator, I planned to mark it, but it seems it is lacking any kind of good place to make a reference mark (see picture at bottom of post #4). Any suggestions there? I know I could set up a temporary pointer arrow for when I initially do the timing, but I am trying to think about timing it down the road. My best guess would be to make a line on the bottom edge that seats against the cover plate just because this is the closest point to the rotor. But I am not sure if this would be visible for timing with the motor in the bike.
 
There is a sticker available from Hugh's Handbuilt I believe that you put on your side cover. Find TDC then mark the stator in line with the TDC mark on the sticker. The other two marks represent 15° BTDC for idle timing ("Fire" mark) and 40° BTDC for full advance ("Advance" mark). I think he'll sell you one for next to nothing .....

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last time I looked Mikes sold DID FTS cam chains, so no need to worry about quality if that’s what you got, I’ve got a couple of them sitting on my shelf for rebuilding Yam 500 single motors, mine are the ones without joining links though.
 
So I am starting to run out of things to do while I wait on tools and parts. I measured my connecting rod big end clearances and my cam lobes and they're in spec. I decided to try to trace all of my wiring and get that figured out for when I reassemble. Electrical stuff is definitely NOT my strong suit but I am reading and learning because it is inevitable that I will have to deal with it while working on anything.

Luckily for me this bike has about the simplest electrical system you could find on a bike probably and things are pretty accessible. I made my diagram based on current wiring positions, pictures from the intact bike, and pictures I took during tear-down. There are a couple places where I had to guess - like where wires disappeared into the frame and then reappeared but this is what I came up with:

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For my handlebar brake lever and my headlight, I have 3 wires going into the central tube of the frame and only 2 come out. So I assumed that the brake lever connects to the tail/brake light in order to light it up when you are braking. And I assumed the wire running straight to the fuse is the headlight. So would it make sense that the other wire from the handlebar brake (where the '?' is in the diagram) is grounded?

I also wanted to check which thick black wire connects to which terminal of the battery because the wires and connectors are identical with no indication of positive and negative so I don't want to hook it up wrong and fry everything. I am a little confused about why the battery would have both leads run straight into the starter solenoid straightaway.
 
I am a little confused about why the battery would have both leads run straight into the starter solenoid straightaway.
Yeah... don't do that. Soon as you energize the solenoid, it's gonna be a dead short across the battery. :yikes: The only thing that'll come of that is you'll get to inform us of which burned up first... the battery or the solenoid. ;)
If that's how it was wired, best you start from scratch. Tech section has some really good basic diagrams for you the work off of.
 
Also... I'd strongly suggest you incorporate a starter safety relay back into the system. Accidentally hitting the starter button while revved to about 5K revs is gonna be catastrophic.
 
is there some kind of secret for getting the locating dowels on the engine bolts out of the head/head cover?
Here's another way. A 5/16" 1/4 drive Craftsman socket on a 6" extension works... or just find one that fits.
stick it in from the backside and give it a few taps.

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My starter motor is currently wired to spin when the ignition key is turned and the ignition key is located on the electrical orb underneath the seat. Is it still a good idea to wire in a starter safety relay even though an accidental activation while riding might be less likely without a starter switch on the handlebars?

Also thanks for the feedback on my electrical diagram. I did not try hooking it up as drawn and I realized I forgot to incorporate the starter motor into my diagram. I think I have the wiring down now but I am nervous to test things out because I have basically never done any electrical diagnosis/troubleshooting/wiring.
 
My starter motor is currently wired to spin when the ignition key is turned and the ignition key is located on the electrical orb underneath the seat. Is it still a good idea to wire in a starter safety relay even though an accidental activation while riding might be less likely without a starter switch on the handlebars?
You would probably be OK if there's no way to accidentally activate it.
 
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