Formula III 700 that ran backwards

[580pluspower]

Here is an interesting tale.

I've seen sleds do some bogus things sometimes, but this one takes the cake. Hopefully someone can shed some light on this occurrence. My father, a friend of his and I went for a local jaunt tonight to the tune of about 50 miles or so. My father was riding his 1999 Formula III 700 triple, which up to now has performed admirably flawlessly, and continues to after the fact. Near the end of the trip, he pulled the cord and the sled started fine, but on takeoff that thing started motivating in reverse. The engine had somehow started backwards, after being pulled the right way. He hit the kill switch, pulled the cord again, and it started the right way this time, but for the first ten feet or so of forward motion there was some undesirable clunks and scrapes coming from under the tunnel, then it cleared up and rode fine.

WTH.

Soo... how could this happen? It doesn't seem as though the sled is damaged in any way, but the ominous noises really gave us a bad feeling. Which leads me to my next question - what could have gone on under there when it backed up to cause such noises? Perhaps ice... The sled drove home fine about five miles back no problems. It has about 750 miles on it. I'm at a loss.

...We might've done more miles had it not been for my fathers friend's El Tigre making an equally ominous clattering engine noise that progressed in volume the farther it went (sounds like a rod/crank bearing, sadly). I'm mildly amused that the only sled that didn't pull any BS was my 780, which now has 50 miles on a fresh top end. Huh.

Any input on the matter is greatly appreciated, as always.

[braindead1684]

IT sounds like it was pulled over backwards Possibly from pulling the recoil to far out and it some how winding up backwards (they should be able do but thats the only way it can really turn over in reverse)

The noise i would assume are from ice and such getting stuch up around the drive shaft and such and breaking free.

[braindead1684]

Impossible.

I knew it was a stretch but the only think that makes sense as the engine would have to be rotating backwards in order to run backwards.

[m_scott]

i have done this. you pull it over one cylinder backfires and starts the motor rotating backwards and since its a 2 stroker they run jut fine that way. Clunking isprobbaly icein the track.

[580pluspower]

Impossible or not, and yep - not April yet. It's not a tall tale. It was witnessed by a few people, myself included, and I don't intend to begin disbelieving my eyes just yet. I'm glad this isn't an isolated case, and while I knew that strokers could run in reverse, I had never seen it happen without the aid of RER or something of that variant.

With all due respect, had I wanted to make up stories, I probably would have told some idiots at work, and saved myself the trouble of looking like an a-hole.

[2doo]

My old RM125 did this quite regularly.

[DRHSpecialty]

A two stroke motor without a fixed valve train can and will run backwards pretty easy. It may not perform like it would it it was running foward but it will run.

Starting it backwards would require all the planets be alighned just right but if it backfired at just the right moment it's sure possible.

You should'nt need an engineering degree or alot of math to understand that it's mechanically possible to do it.

[DamageInc]

If two stroke sleds fired only once per revolution (before TDC), I don't think it would be possible. But most two strokes fire twice (one is wasted), so that extra spark is the one that could possibly allow it to fire up in reverse. All it takes is a backfire on start-up (very possible, especially if it's a warm start and you didn't allow it to idle down when you shut it off). But it's certainly a rare phenomenon. I've never experienced it, but I know a couple people who have.

[The Great One]

I had a zr700 that I had worked on years ago do this. Fired up in reverse everytime. Found out after I tore it back apart(just the flywheel) I had hooked the stator wires up backward. Instant electronic reverse. Dang shoulda patented it.