The SG's Top End Swap out.

azman857

'80 XS 650SG Rider
Top Contributor
XS650.com Supporter
XS650.com Supporter
Messages
2,724
Reaction score
5,077
Points
513
Location
Tucson AZ
Well, after a good night's sleep and the Sat morning Carl's Jr breakfast I blew of 2 car shows and dived into the swap out. The previous night, I had started prepping. Removed the tank, the exhaust and started disconnecting electrics. Today, the rest of the stuff in the way of engine removal got out and the engine is removed. After lunch the valve cover was removed. Seems the rockers were wearing out on the cam. A distinct wearing line about mid pad. I got the cylinder block off with the head. for some reason the head is stuck on. Pistons look OK. Some minor scuffing. Normal wear stuff. I'll measure it all out later. Yes, pics are coming.
 
Some pic of Sat. progress.
PC050429.JPG
PC050430.JPG
PC050432.JPG
PC050433.JPG
PC050434.JPG
PC060436.JPG
 
I was so surprised to find my front cam chain guide was in perfect condition! As one can see, this is happening in my bikeport. No cars allowed so it's not a car port. I still have to finish the rocker arm mods for the bigfoot adjusters with the thinning of the end of the arm to aprox 8.5 mm and assemble the head with the installation of the valves. I did install the pistons into the cylinders last night.
 
The reason for all this is because of low power. I got tired of quickly losing speed when climbing hills. The installed the 256 cam during the last engine update. Next to the installation to the PAMCO with Electronic Advance as to one of the best things I've done for this engine. A compression check some time back was around 120-125. Not knowing if it was due to rings or valves, I thought it best to swap it all out.
Tupperware? I don't do Tupperware. That and the reason I don't plan on being off the road that long. Temps are in the low 90's- Upper 80's around here. That's riding time!
 
I thinned out the whole end of the rocker on my first couple elephants foot adjuster installs .....

d4GSTWu.jpg


..... but I don't do it that way anymore. Now I just bevel cut into the bottom of the rockers with a tapered stone in a die grinder .....

lwjU668.jpg


1LHlrDh.jpg


9PEULFb.jpg


This has a couple advantages. First, you're not removing as much material as before, and second, it can be done with the rocker still installed in the top cover. You just wrap rags all around it .....

VeHZr9M.jpg


27eshIi.jpg
 
TM It's just the rings area that are in the cylinder block. Just the inner clips are installed
 
I thinned out the whole end of the rocker on my first couple elephants foot adjuster installs .....

d4GSTWu.jpg


..... but I don't do it that way anymore. Now I just bevel cut into the bottom of the rockers with a tapered stone in a die grinder .....

lwjU668.jpg


1LHlrDh.jpg


9PEULFb.jpg


This has a couple advantages. First, you're not removing as much material as before, and second, it can be done with the rocker still installed in the top cover. You just wrap rags all around it .....

VeHZr9M.jpg


27eshIi.jpg

YUP - this is how the adjusters on Lucille were done and it seemed to work out great!

Pete
 
Well past time for an update. All 4 piston pin clip tangs were shortened. Last night the cylinder block and pistons were installed. THAT was wrestling match! I won though. The installation of the head was way less drama. I couldn't do any tightening due to a lost 12mm socket. It was late anyway. The chain guide was installed along with the can chain tensioner plate to the cylinder block. Found another 12mm socket so progress will be made again. Let's see some pics.
PB070455.JPG
PB070453.JPG
PB070457.JPG
PB070456.JPG
PA300450.JPG
PA300451.JPG
 
Did you install the cylinder block before putting the front guide in? There's no way to insure it's in there straight, perfectly centered top and bottom, if you do.
 
It may be just me but I would be concerned with the amount of rust on the springs and tops. The rust isn't going to hurt the metal but I would not like it coming off and going through the engine. You may want to think about cleaning of the rust and oiling the steel parts down. You're in AZ I didn't think rust happened there.
upload_2019-11-8_15-58-50.png
 
5Twins, I put the guide in after the block and cam was in. Shined a flashlight down and it's centered as much as I could see.
I did have a bit of a scare. Got everything torqued up and valve cover on and even the caps and oil tube. Then I had a thought. I know, a dangerous thing, but it happens. Took the adjuster covers off and shook the rockers to make sure there was lots of clearance. Advancer side lots of wiggle. Iggy side....none! OMG!! Visions of taking apart the valve cover and more grinding and reassembling ….Then I got a revelation....This is OK . Valve timing . All is well. Sure enough, rotated the crank in revolution and lots of wiggle. WHEW!! How about some more pics. I know there must be a 100 or 1000 of pics with the engine in various stages of dis or re-assembly but, what the hey. Here's mine....Oh yeah.. I put some oil down the adapter where the oil tube is. About 4 capfulls. Did the same at the valve cover. Where the tubes meets the cover. Greased up the lobes on the cam and the rockerpads. After a bit, Motor installation in the frame!
PB080459.JPG
PB080460.JPG
PB080461.JPG
 
GLJ, I thought about that too and your right. I should have run the wire brush over everything. I'm a bum. I did run it over to the parts washer and got the loose stuff off. Yes it does rain in AZ. I got this parts motor from a M/C junk yard and it was in open storage. Who knows how long. Got some other parts with it and no rust on them.
 
GLJ, I thought about that too and your right. I should have run the wire brush over everything. I'm a bum. I did run it over to the parts washer and got the loose stuff off. Yes it does rain in AZ. I got this parts motor from a M/C junk yard and it was in open storage. Who knows how long. Got some other parts with it and no rust on them.
I think I would do a couple/3 quick oil changes. Rust is like grit to a engine.
 
That came to my thoughts too. Break in oil changes. New pistons and rings and all
My plans for this engine is this. To run it until the present KZ/GPz project bike is roadworthy/reliable. Then the SG gets redo. Hope to include a rebuilt crank, a touring Megacam. Re do the electrics and get the unused wires out. Some new paint and whatever else I can think of. I hope to get the KZ out within a year or less.
 
Last edited:
Back
Top