No worries...  if you rotate backwards, you can mistake the compression stroke, for the exhaust stroke, when setting valve timing...
Suck, squish, bang, blow.... you'know?...

...might also effect valve lash, when you measure gap... if you entered backwards....

You did know harm...

Just don't do it so much, that your bike thinks that's what you want...
It's very gullible...

Now, you get a Detroit Diesel in a forward gear and kill the engine, pushing in the clutch and let the truck roll backwards, pop the clutch, and you'll have it running backwards.

The
Turn the motor CCW instructions are important for engine work.
Getting it off compression to make it easier to start? It dont care.

But wait, that means the supercharger in there would be sucking out ou the intake making a vacuum, instead of pressurizing it. I think.

Redryder652 wrote on 02/07/16 at 07:00:12:


The engines JOG is talking about are the old Detroit Two strokes, and they will indeed run backwards, just like he described. They suck air in the exhaust and exhaust out the air cleaner.

A lot of them were naturally aspirated, especially the LN4's and the LN6's and none of them were supercharged. The ones that were not naturally aspirated were turbocharged.and if you got one running in reverse the impeller in the turocharger didn't spin fast enough to make any difference since it was then on the intake side - no exhaust gas to make it turn.

Emissions regulations put an end to those engines quite a while ago. There are probably some still around 'cause they were very long-lived, reliable engines, particularly in construction equipment and stationary generators, but GM hasn't made them for pretty close to twenty years.

Redryder652 wrote on 02/07/16 at 00:03:58:

To answer your question... I hope you have a '95 or later bike!
Anything built prior to that doesn't have a starter torque limiter.  Rotating the engine backwards will engage the starter clutch.  It takes a lot of torque to turn the starter and most times teeth will just break off instead or the journals for the gear shafts will break out.