1980 Engine Top End Rebuild

[JTD1989]

One problem with the current set-up is it uses a generic ignition switch that uses what looks like a lawn mower key to start the bike and I'm pretty sure ignition switches of this style are not secure at all and can be started with many similar style keys.

Makes me nervous I might park the bike somewhere and someone will just hop on and ride away. Especially living in LA...

 

[650Skull]

Original XS650 Yamaha ignition switches are far from being secure..........just jam a screwdriver into the key slot and twist.........Must have been done to mine, (83), before i bought it. i could use the edge of a 5 cent, (Kiwi), coin to turn the ignition on

 

[JTD1989]

Wow that's pretty crazy. Well I guess I need to get it running first then I can worry about ways to prevent someone driving off with it. So I revised my wiring diagram and this is what I came up with.

I couldn't find an exact wiring diagram match in the tech section thread with all of the stripped down diagrams. Does it make the most sense to worry about the wiring once the motor is in the frame? Is it possible/a good idea to test electrics before putting the motor in?

 

[650Skull]

If your only running the Panco and coils off the one fuse make it a 7.5 amp........... Pamcopete recommendation

Run a power wire from the battery through the fuse box to the ignition switch with a 20 amp fuse...........eliminate the doubling up of those other fuses from the ignition

Need a switch/button on the power wire between the ignition and starter motor

No fuse's on Black, (earth), wires.

Go through these diagrams..........They have a breakdown of each circuit and combined they overlay to make up what ever system you want
http://www.xs650.com/threads/simplest-working-wire-diagram.57198/#post-642337

 

[JTD1989]

Thanks I appreciate the advice 650Skull. I will continue reading and researching on the wiring and hopefully by the time I am finishes with the engine and have it in the frame I will have some idea of what I am doing with the electrics.

Here is an update on what I have been up to in the last week or so and I apologize for the hazy photos but my camera case has some permanent smudges over the camera part due to taking pics while working on the bike:

I cleaned the fuel tank with diluted battery acid then neutralized and cleaned with washing soda. Then I lined the tank with Kleen fuel tank liner:

I removed the valves, cleaned em, checked for play, made sure the stems are straight then lapped them:

I performed a leak test with solvent on each valve and didn't notice any leakage.

Next my 1st oversize pistons and rings came from Mikes and I took my jugs to the local machine shop to be bored out and then honed. He charged $50 a cylinder which I thought was reasonable compared to over $200+ I was quoted at another shop. I measured them with my T gauge in six spots per cylinder and they did a pretty good job.

After seeing my cylinders were good to go I finally was able to start rebuilding. I followed Jim's Top End Buildup thread along with multiple other threads on the forum to answer specific questions I had along the way. It went a little slow seeing as how this is my first major motorcycle engine work, but I was able to get it all done in two days thanks to having a little extra time off lately.

 

[JTD1989]

Here are the freshly honed cylinders

 

[JTD1989]

First I did a thin bead of Permatex oil resistant gasket sealer above and below the base gasket. I read many different opinions on this, but hopefully it doesn't hurt to have the sealer even if it isn't necessary, especially since I am using the basic Mikes gaskets.

Next I did new copper washers on the cam chain guide bar bushings (guide nuts?) and bolts. I decided to keep the original guide nuts and bolts since they seemed fine and the guide nuts from Mikes were longer than the originals.

I placed new o-rings on the bottom of the cylinders and started checking the gaps on my rings as Jim described in his buildup thread.

I discovered that the rings were produced very consistently dimension-wise and one of my cylinders is about .01 mm larger in circumference than the other since each ring I tested in both cylinders had a .01 mm difference in gap from one cylinder to the other. The skirt measurements on the new pistons were the same to two decimals in mm. Here they are taped up and ready for the ring installation. The electrical tape was great advice and definitely prevented some piston scratching carnage from taking place:

Next I taped on a little cheat sheet to help me line up the ring gaps after installation based on the diagram in the manual:

Then with a little frustration I got the rings on:

And I will continue with the rebuild update in the next post.

 

[JTD1989]

Once I got my rings in place I covered the inside of the cylinders in oil and put my pistons in the cylinders from the bottom without too much trouble. And then I got set up to put the jugs back on the crankcase:

Then I added a thin bead of Permatex black and pushed the jugs down. The pistons stayed at TDC.

 

[JTD1989]

Next up was the heads. I installed the front can chain guide with new copper washers and put a thin bead of black Permatex below and on top of the head gasket. Hopefully I don’t end up regretting that.

I placed my oil baffle in the head but forgot to take a picture. Then I slid the head on and prepared for the real bear of the rebuild for me: the cam chain

 

[JTD1989]

I really could have used a second person here, but my girlfriend didn’t have much interest in helping out I had a scare first of all with dropping the cam chain on one side. It had wire on it but I was moving it and dropped one side. It dropped about halfway down but I was able to recover it with a telescoping magnet. My eBay chain breaker tool pushed the pin out of the old chain with no problem.
I put the two bearings on each side of my camshaft and placed the camshaft in position with the large tick mark facing up. Then I made sure the crank was still at TDC and I started trying to get the chain on. I pulled as hard as I could and it didn’t seem like enough to get the chain on so I used some sockets and washers on the engine studs to allow me to screw on the head bits to tighten everything down. I pulled as hard as I could again and again and it still didn’t seem like enough. Finally I decided to just go with it and see if I was wrong and it turned out I was wrong. Once I had tags stuffed in the cam chain gallery to hold them tight onto the cam gear and I removed the wire, sure enough the chain was in proper position to get the master link in. I popped it in and then check to see if the crank/cam were still in position after all the finagling and my cam was slightly off
But now I know that when it looks like the two ends of the chain are nowhere near close enough to get the master link in, you actually may be good. So the second time around it went waaaay easier.

But this was only the beginning of my woes. When I went to use my eBay chain tool to river the new master link, which I thought should have been the easiest part of this ordeal, it turns out the steel in the master link pin was harder than the steel in my chain tool so instead of smashing the end of the link (which was already dimpled/hollow to facilitate riveting) it just marred my riveter up. Eventually I got both pins riveted by reworking my riveter in my drill with a flat file in order to give it more of a rounded point. You can see the imprint from the end of the link pin in the end of the soft steel In my riveter in the picture. I spent way too long getting those two little pins riveted...

I measured the width of the rivets afterward and they were sufficiently large to make me comfortable. I didn’t write the measurements down though so I can’t recall what they were now. I didn’t do much documenting through the cam chain process because it was so difficult and intense. Props to all of you who not only have done this without a second set of hands, but also thoroughly document it.

Finally, I put a bead of Black Permatex down and Poured some motor oil on the bearings and down the cam chain then greased the cam lobes. One question I had at this point was how I know the camshaft is centered, but eventually I discovered it is the points and advance unit housings that center it. This seemed kind of strange to me though. My tappet screws were backed out so the head cover went on easily.

 

[JTD1989]

I took the gaskets and o-rings off the housings and screwed them in each side to center the camshaft more accurately as Jim suggested in the Top End Rebuild thread.

and then I removed the housings, put a bead of Permatex black on each side of the gasket, installed the o-rings and new cam end seals and reattached the housings. The cam seals were thinner than OEM as Jim mentioned and I installed them flush to the inboard flange on the housings. This left a small gap on the outboard side.
Then I reinstalled my oil feed line with all new copper washers. I also used a small amount of black Permatex on these washers. I’m not sure if that’s a good idea or not but I figured I can unscrew it and remove it if I need to.

and finally I installed my cam chain tensioner.

I destroyed the gasket when I took it out and this gasket was not included in the Mikes top end kit so I am waiting for the tensioner gasket, sump plate gasket, and oil filter gasket from Mikes right now. I used black Permatex on the sump plate and tensioner temporarily to reassemble and put oil in just to make sure the oil pump is functional. Is that a bad idea? Will oil go everywhere if I kick it over a couple times to check oil flow?

 

[Bushyeyed1]

If you want to know what happened to prompt that repair in the cylinder head I know first hand what happened. The valve rocker adjuster and nut popped out and the cam smacked it around. I was going to get a machinist to fix mine but it was just as cheap getting a used cylinder head.

 

[JTD1989]

Wow that’s crazy. That is exactly what a friend of mine suggested based on a picture of the damage. It ended up in my left cylinder and scratched and dented my left piston too. That must have inspired the previous rebuild. So what can I do to prevent this from happening again? Do you just have to tighten the lock nuts crazy tight? I just adjusted my valve clearances and they were on there really tight this time haha

 

[Bushyeyed1]

No you don’t have to go crazy on the torque, i just get them on good and tight now. There is a torque value and don’t quote me but I believe it Is between 12-18 ft ibs. I don’t use it but don’t let me stop you. The reason it happened for me is the old lady yelled at me to come do something mid adjusting the valves and I guess I didn’t tighten that one.

 

[JTD1989]

Oh wow, I will try to stay focused long enough to tighten all four haha.

 

[5twins]

The only possible error I see in your rebuild process is it doesn't look like you centered the front cam chain guide in the tunnel when you installed it (post #29, 2nd pic)? That will have the chain running sort of diagonally across it and mess it all up, like these old ones .....

All three of these were mounted off center, the right one in particular.

 

[Jim]

With your crank at TDC the notch in the cam should have been flush to the head face. Was it?

 

[5twins]

No, the notch sticks straight up, the dot on the other side of the cam is level with the gasket surface.

 

[JTD1989]

Thanks for the feedback 5twins. That was one step that I was not completely sure about. I held the cabin up and tried to sight it by looking square at the front of the engine and it appeared straight to me but I am not very confident about that. If I am going to go back in and fix that, what is a good way to measure for centeredness? Make sure each edge of the guide is equidistant to the edge of each cylinder? Will it destroy my gaskets if I go back in after using Permatex black on both sides?

 

[JTD1989]

To answer your concern, Jim, I had the notch on the left side at 12 o’clock and the simple on the right flush with the mating surface, but in this picture I had rotated the cam and crank to make it easier to get in to the master link pins. I will check when I go in to straighten out my front cam chain guide though. Thanks for your comments.