I am rebuilding a 1980 1000, on inspection of engine all looks good. Checked cams, primary, clutches, and all looks good. My problem is when I received this engine top end was missing. I have checked rods and all checks out. My question is now, should I split the cases or not?? flywheel is pretty clean, no rust.I thought about flushing the cases with diesel and rebuilding top end. looking for thoughts on this.thanks

 

If you've come this far...you might as well go all the way. Especially if you don't know the history, if the juggs have been off for a while and there is some question of how clean it has been kept.

It's 30yrs old...it's time to redo the seal in the cases.

 

There are two tests in the manual for the bottom end that can be done with the top end off - testing the rods for up&down play there should be absolutely none, testing flywheel end play which should not exceed .007". If it passes both of these tests then you do not need to split the cases.

Another good choice for flushing is kerosene. With flushing however you do not want to flush out needed lubricants - i do not know about this.

I do not have experience myself with splitting the cases. There are technical challenges that are beyond my knowledge, experience and tools - so i always have my indie do this when needed. This is not a task for a beginner. Do a thorough reading of the factory service manual and determine if you have what is needed.