Will a '71 XS650 motor bolt directly into a '74 TX650A frame?

[OhTimothy]

Hey guys - the engine in my 74 TX650A began making bad bottom end noises about a week ago, and I've been looking around for another engine I can put in my bike. I found a 71 XS650 and I'm wondering what - if any - significant differences there might be between these engines/model years.

1) Are the motor mounts the same dimensionally?
2) Does the 71 engine and tranny have a transmission sprocket with the same chain pitch?
3) Other dimensional or compatibility problems?

My 74 engine has an electronic ignition module upgrade instead of points, and I've gone through, cleaned, and set the float levels in my 74 carbs - that engine ran GREAT until the crunchy bottom end noises started. I intend to transplant my 74 carbs and carb stubs over to 71, and also put the ignition module on the 71. I don't anticipate any problems there...but am I missing anything?

Thanks for your input!!

 

[Jim]

71 motor does not have provisions for electric start.
But yeah.... it'll fit.

 

[gggGary]

Use the mounts from the frame not the motor.
The front mount hole on the 70 motor sits about 10mm further back than all the later years. Other than that yes the 71 should bolt...