Engine assembly woes

[h3llb3nt1]

Bike ran when I bought it. Tore top end of engine down just because it needed refreshing. Cleaned and polished and cleaned some more. New endless cam chain and seals only. Everything else was glass beaded and wire brushed. I can turn crank with cam in and top off. Did final assembly and torqued everything down to speck. Now I can only turn crank about half way from top dead center and it stops. I am doing this by turning the rotor. went wrong? I have had it apart twice now going through the steps to no avail. Anyone have good news for me? Oh yeah its a 78 special. Or it was anyway. Thanks in advance.

 

[5twins]

Sounds like you didn't time the cam properly. Valves are opening at the wrong times and contacting the piston(s), stopping the engine from turning.

 

[I am Carbon]

h3llb3nt1, I have to agree with 5twins.
this is where the cam and ccank should be

 

[5twins]

The location of the master link doesn't matter, as long as it's on top of the sprocket somewhere so you can access it for riveting. In fact, if your alignment marks are correct, you can rotate the motor slightly to move the master link right to the top so it's easy to work on. Once riveted, realign the timing marks to insure cam timing is correct. It's also a good idea to turn the motor over a revolution or two and check the marks again. Someone recently didn't do this check and had to take the whole thing apart again because he was a tooth off. Check it now while the motor's still on the bench and semi-disassembled, not after it's fully assembled and back in the frame.

 

[deadchef]

fortunately mine was only off a tooth and didn't destroy anything. on the other hand, it was a bitch trying to figure out wtf was wrong since the bike still ran...

http://www.xs650.com/forum/showthread.php?t=20439

 

[h3llb3nt1]

Appreciate the quick responses. Had the cam lined up correctly and at tdc. Figured it out. I'm embarrassed to say but, I had the valve spring top washer clip upside down. Reading and reading the steps and I happened to look at a schematic and sure as shit, there it was. Cant believe I did that. No wonder it was so hard getting those little clips on