Mike2735

My Feedback: (3)

I have an SV50 cc twin 2 stroke gasoline engine. It is crank trigger fired. I was wondering if there is any reason I can't modify the crank trigger so the engine would run in a clockwise direction as opposed to the counter clockwise direction it runs now? I have a project that requires the engine to run clockwise.

Thanks in advance for you responses.

Mike M.

av8tor1977

My Feedback: (6)

That could be a tough one. Reed valve or piston ported two stroke engines can be made to run in either direction just by changing the ignition timing. However, with a twin you could possibly run into problems with one cylinder running richer than the other if you make it run backwards to the way it was designed. If the engine had individual carbs for each cylinder, that would not be an issue.

Another issue with making them run "backwards" is that the prop hub and/or prop retaining bolt or stud needs to be left hand thread to run in reverse. Otherwise the power strokes act like an impact wrench, quickly causing the prop hub or prop to come loose. Careful with that, as the prop can come right off in a lively fashion. (Don't ask me how I know....)

AV8TOR

Mike2735

My Feedback: (3)

Thanks for your response. This is a reed valve engine. Both pistons are in the compression (outward) stroke at the same time. Thanks for reminding me about the retaining nut. I will have to make sure I use a nylon locking nut and possibly a jam nut with it.

tande

My Feedback: (48)

Aahh.......Not recommended....

WRK

My Feedback: (2)

If you pull about the same RPM in the reverse direction with a similar prop you are good, I think it will probably work.

Mike2735

My Feedback: (3)

Thanks Everyone. I am going to try it this week end to see what happens.

Cyberwolf

My Feedback: (4)

Use some blue locktite on the original nut instead of the nylon nut and tighten it up good all should be good to go.

av8tor1977

My Feedback: (6)

I've tried double jam nuts, the high strength RED Loctite, and I've even tried thin super glue, (CA). The props still come loose when the engine runs backwards. Be careful.

AV8TOR

Mike2735

My Feedback: (3)

This engine is not actually going to be turning a prop. It will have a pulley on it turning 2 ducted fans. (A project I am working on. The fans need to face forward and the motor would mount better if it was mounted facing the rear. That's why it needs to run in reverse.)

tande

My Feedback: (48)

Oh, well now.......a completely different argument from a "Safety" point.......if it were a prop & you choose to put yourself in harm's way, that's one thing......to include everyone around you ,is another story.......