Monday, February 21, 2011

Yamaha XS650 Valve Cover Off

After several hours of wrestling with corroded fasteners the valve cover finally decides to come clean. On the right side of the engine are the advance weights and on the left side are the points which operate directly off the cam shaft. There are four covers that allow access to each of the vales, these had to come off as well and were easy to remove. The problem came when trying to remove the points plate and the weight plates. All the buggerd up heads on the small screws made it a challenge and only one screw - on the weight side - was rusted so bad the phillips head slot went way down south. A screw extractor was tried only to have the head of the screw snap clean off level with the surface. It will have to be drilled out and retaped on reassembly.  

Here is the under side of the cover removed. It was pleasingly cleaner than expected although those rockers need a good inspection but to the first time of building one of these engines I'll need to compare to a new set or get advice from the dealer parts counter. Of course, I could have John from over at Superfly Cycles have a gander.
 In this picture you can see the timing chain that runs from the crank all the way to the top side right through the center of the engine. Now how to get that sucker off the cam shaft. To find out I've contacted Hugh at HughsHandbuilt.


This shaft here goes through the cam shaft and links the fly weights on the right side of engine to the points on the left side of engine. Pulling this out is easy enough. This shot is of the points side of the shaft.

Now here is a little problem I've encountered. This rusty piece on the camshaft is a problem, the roller bearings won't come off over this and I'm not sure if it is pressed on or rusted on.

Here is another close up angle of the rusty end that is keeping the bearing from coming off the cam shaft; was this supposed to come off with the rest of the center shaft?  Look at those ball bearing bearings there would you. No wonder these engines last so well and take such abuse. That's pretty hefty of a design if you ask me. These engines were meant to give many miles and years of service and is evident how well they stand up don't you think.


Billy Jones said...

Wow, you're coming right along! Not bad for your first peak inside one of these things.

The book is no problem and the alternator puller can come with it.

I'm supposed to get the hardtail frame back the end of the week. Looks as if all my bikes are going to be down at the same time.

WooleyBugger said...

Not bad for flying blind with it and having some fun doing it. Some bits will need replaced, mostly fasteners and normal items so far. There is no gasket on the valve cover and I heard they used some sort of thin sealant on these engines.

Yeppers, that book and puller will be a definate help.

Can't wait to see the hard tail frame myself. Is it a perhaps a bad valve guide on Nothin Special?