crankshaft blues

[randeman]

When I bought my basket case '72 XS2, I couldn't get the engine to turn over. I thought it was frozen, so I filled it with diesel and Marvel Mystery oil for weeks and still could not get it to move. Removing the engine and pulling the head, to expose the pistons, I thought that I could tap on them and get them to move. No such luck. Would not move. After losing my cool and beating the s--t out of them , nothing. I beat the cylinders upwards and finally got them off of the pistons. The crank would turn about a 1/4 turn and stop. I looked down in the engine and found that (2) of the lead counter weights had come out of the crank shaft lobe and were hindering the crank from turning. I have since split the cases and am in the process of getting another crank assembly to replace it.

Has anyone incurred this problem before?

 

[gggGary]

First I've heard of it on a 72, I think there was a thread about this issue with a 75 motor......

 

[NONclow]

Yup. Time for another crank/flywheel set.

http://www.xs650.com/forum/showthread.php?t=27461

 

[angus67]

My rods were wobbly on the wrist pins, so instead of replacing the con rods, i just replaced the whole shouting works with a lower mileage unit for $80. Easy

 

[randeman]

You guys are good, especially nonclow. This is exactly what happened to my engine. This bike was up North for all it's years. The extreme cold and then hot had something to do with the counterweights falling out. Hope not to have this happen in Houston weather where it is always hot. I still have this picture in my mind of tearing down the road at 80 mph and then they decide to come out and lock the crank.
I have bought a crank assembly off of ebay, said it was from a '72 xs650. Dumb a-- me. I didn't catch it. the '72 is an XS2 not an xs650. I put most of it back together and then tried to connect the pistons. My luck, the piston rods have 20 mm holes, not the 22mm , like I need. Oh well, getting another one and have to tear down everything to put it in. I am getting a lot of practice on this engine. Should be able to do this right , one day.

 

[gggGary]

Yup. Time for another crank/flywheel set.

http://www.xs650.com/forum/showthread.php?t=27461

Thanks nonclow that was the one I was thinking of.

 

[NONclow]

You guys are good, especially nonclow. This is exactly what happened to my engine. This bike was up North for all it's years. The extreme cold and then hot had something to do with the counterweights falling out. Hope not to have this happen in Houston weather where it is always hot. I still have this picture in my mind of tearing down the road at 80 mph and then they decide to come out and lock the crank.
I have bought a crank assembly off of ebay, said it was from a '72 xs650. Dumb a-- me. I didn't catch it. the '72 is an XS2 not an xs650. I put most of it back together and then tried to connect the pistons. My luck, the piston rods have 20 mm holes, not the 22mm , like I need. Oh well, getting another one and have to tear down everything to put it in. I am getting a lot of practice on this engine. Should be able to do this right , one day.

Thanks! Get more engines/bikes to practice with too!

Thanks nonclow that was the one I was thinking of.

No problem!