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Good spark only in revers???!!!

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I have a 1982 kx80 if i take the spark plug out put it in gear and roll it forward it only has spark if you roll slow but if i roll it back wards the spark is perfect but i cant start it back words of course i have no clue what it could be i need help

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Check for sheared woodruff key on the flywheel/crank. My KDX 175 ran backwards because of a sheared key letting the flywheel lock back up over TDC, allowing the engine to run backwards... -BIG DAN:thumbsup:

http://www.youtube.com/watch?v=7ManjrJUXp0

Does the bike start at all????

I have a funny story about a sheared woodruff key. I had a Hodaka Combat Wombat. At my first race, we were at the line and the bike stalled. It took several kicks to start it back up, but it seemed fine. When the flag was raised, I started revving the bike along with everybody else, and when the flag dropped I dumped the clutch. The bike took off backwards, tossing me over the bars. Nobody could believe that actually happened as they were picking me and the bike up...👍

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I have a funny story about a sheared woodruff key. I had a Hodaka Combat Wombat. At my first race, we were at the line and the bike stalled. It took several kicks to start it back up, but it seemed fine. When the flag was raised, I started revving the bike along with everybody else, and when the flag dropped I dumped the clutch. The bike took off backwards, tossing me over the bars. Nobody could believe that actually happened as they were picking me and the bike up...👍

wow, circumstances were just right

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I have a funny story about a sheared woodruff key. I had a Hodaka Combat Wombat. At my first race, we were at the line and the bike stalled. It took several kicks to start it back up, but it seemed fine. When the flag was raised, I started revving the bike along with everybody else, and when the flag dropped I dumped the clutch. The bike took off backwards, tossing me over the bars. Nobody could believe that actually happened as they were picking me and the bike up...👍
That's why you always bring a camera to the races, I'm sure that would have been worth $10,000 on America's Funniest Home Videos. Seriously, that audience will laugh at anything, the more pain, the more votes.

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I have a funny story about a sheared woodruff key. I had a Hodaka Combat Wombat. At my first race, we were at the line and the bike stalled. It took several kicks to start it back up, but it seemed fine. When the flag was raised, I started revving the bike along with everybody else, and when the flag dropped I dumped the clutch. The bike took off backwards, tossing me over the bars. Nobody could believe that actually happened as they were picking me and the bike up...👍

I had a Hodaka Dirt Squirt that I stalled on a steep hill and with the small amount of compression it rolled backward just fast enough to start backwards. I ended up in a pile at the bottom but it taught us we could start the bike by pushing it backwards and then try to ride it. Those were the days....

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That's why you always bring a camera to the races, I'm sure that would have been worth $10,000 on America's Funniest Home Videos. Seriously, that audience will laugh at anything, the more pain, the more votes.
Well this was a bit before the age of digital camcorders.🤣

I'm sure somebody somewhere had a home movie of it though...👍

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Not that I'd ever want to see anyone get hurt, but from a mechanical stand point, I would love to see a video of this type of event. First off, I know it's not unheard of, but it blows my mind that a two stroke engine turning clockwise (looking at it from the right) via the kick-starter could miraculously fire at just the right moment (after kick-starter disengages) and wind up running backwards w/o the rider knowing. For instance, I've mentioned this before, but my XT550 has a ignition problem a buddy and I are working out. During one of the early attempts to fix it, it misfired, probably 40, maybe 50 degrees advanced which spun the crank backwards, the kick-starter was still engaged so this transferred back directly into my foot and threw me off the damn bike. It's been eight months, I think my ankle is still partially screwed up. So that miracle of impeccable timing is a real "whoa" moment.

I understand the 2T engine that when turned backwards will run just like it does forward. Perhaps with the exception of modern KIPS and similar technology, everything will work perfectly. In fact, there was a two stroke car who's "reverse" was turning off the engine and running the starer backwards. I'm sure parallel parking was fun.

And well, yeah, I'm sure a 1/3 or so throttle free rev, clutch dump, surprised rider would be bordering on hilarious assuming A: you're not the rider in question and B: only the rider's ego gets bruised.

Purely for further mechanical knowledge interests of course.

I'm off to youtube, there has to be a video of this somewhere.

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Thanks, but I'm really looking for the unintentional, "ignorant" ones (as in unknowing, not as in dumbass).. I'd venture to guess that guy simply rolled that old IT backwards and dumped the clutch. And there's no "oh shi--" flop. Gotta have the flop. For furthering the knowledge of all mechanically inclined of course.

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I would love to see a video of this type of event. via the kick-starter could miraculously fire at just the right moment and wind up running backwards w/o the rider knowing. I understand the 2T engine that when turned backwards will run just like it does forward.

Thanks, but I'm really looking for the unintentional, "ignorant" ones

Exactly what happened in my video. I didn't know the crank had sheared the key. And by some MAGICAL luck, the sheared peices lodged back in where the engine was exactly 15 degreed ATDC. (Which is opposite the normal 15 BTDC.)

The kick starter did give a few wild kickbacks at first, so I changed my method to quick release from the kick lever allowing it to snap back into tucked position. Engine started perfectly like this and bump starting FORWARD but the engine ran backwards. When bump starting I would use the clutch to just kick the engine over and then pull it back in when I would get a slightest spark/idle. Ran backward everytime. It ran goodish... never got into the powerband obviously.

Finally got the camera out to show what was going on. But sorry... NO FLOP. It was after a rebuild, so I was in the backyard, and thusly I didn't go for the holeshot. Almost got me over the bars the first time, but I'm 280+ which is hard to topple. But I was TRUELY "ignorant" to the fact that it was running backwards. Truely. -BIG DAN:thumbsup:

Check for sheared woodruff key on the flywheel/crank. My KDX 175 ran backwards because of a sheared key letting the flywheel lock back up over TDC, allowing the engine to run backwards... -BIG DAN:thumbsup:

http://www.youtube.com/watch?v=7ManjrJUXp0

Does the bike start at all????

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Exactly what happened in my video. I didn't know the crank had sheared the key. And by some MAGICAL luck, the sheared peices lodged back in where the engine was exactly 15 degreed ATDC. (Which is opposite the normal 15 BTDC.)

The kick starter did give a few wild kickbacks at first, so I changed my method to quick release from the kick lever allowing it to snap back into tucked position. Engine started perfectly like this and bump starting FORWARD but the engine ran backwards. When bump starting I would use the clutch to just kick the engine over and then pull it back in when I would get a slightest spark/idle. Ran backward everytime. It ran goodish... never got into the powerband obviously.

Finally got the camera out to show what was going on. But sorry... NO FLOP. It was after a rebuild, so I was in the backyard, and thusly I didn't go for the holeshot. Almost got me over the bars the first time, but I'm 280+ which is hard to topple. But I was TRUELY "ignorant" to the fact that it was running backwards. Truely. -BIG DAN:thumbsup:

Ah... I didn't see the kick-start, but it was obvious that the rider was aware of the problem. It's amazing how it could get exactly 30 degrees out of sync. The flop though? I think anyone who expects a forward acceleration would lean forward, and combined with the bike jerking backwards would get the rider over the bars, 80 lbs or 280 lbs.

I'd still rather have a flop than a toss like I got.

IIRC around 30 seconds is where it gets me.

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Nice... just what I experienced when starting the KDX. Two strokes never cease to amaze me... -BIG DAN:thumbsup:

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Not that I'd ever want to see anyone get hurt, but from a mechanical stand point, I would love to see a video of this type of event. First off, I know it's not unheard of, but it blows my mind that a two stroke engine turning clockwise (looking at it from the right) via the kick-starter could miraculously fire at just the right moment (after kick-starter disengages) and wind up running backwards w/o the rider knowing. For instance, I've mentioned this before, but my XT550 has a ignition problem a buddy and I are working out. During one of the early attempts to fix it, it misfired, probably 40, maybe 50 degrees advanced which spun the crank backwards, the kick-starter was still engaged so this transferred back directly into my foot and threw me off the damn bike. It's been eight months, I think my ankle is still partially screwed up. So that miracle of impeccable timing is a real "whoa" moment.

I understand the 2T engine that when turned backwards will run just like it does forward. Perhaps with the exception of modern KIPS and similar technology, everything will work perfectly. In fact, there was a two stroke car who's "reverse" was turning off the engine and running the starer backwards. I'm sure parallel parking was fun.

And well, yeah, I'm sure a 1/3 or so throttle free rev, clutch dump, surprised rider would be bordering on hilarious assuming A: you're not the rider in question and B: only the rider's ego gets bruised.

Purely for further mechanical knowledge interests of course.

I'm off to youtube, there has to be a video of this somewhere.

I'm a bit confused by your posts. Do I understand you to say that you have serious doubts that, since the engine is being kick-started, it can't start backwards without the rider knowing? 'Cause I have first-hand experience that it certainly CAN happen.

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Iv cleaned the stator and fly wheel the key way and key are fine iv re wired the cdi to stator and the timing is perfect new spark plug and coils and i now the wiring is correct

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The bike wont fire at all i haven't tried to start it backwards im having the stators re coiled hopefully it works

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I'm a bit confused by your posts. Do I understand you to say that you have serious doubts that, since the engine is being kick-started, it can't start backwards without the rider knowing? 'Cause I have first-hand experience that it certainly CAN happen.

Me too! A 350 Bultaco Alpina will def. start backwards with a weak stab at the kickstarter and you wont know till you dump the clutch.

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I'm a bit confused by your posts. Do I understand you to say that you have serious doubts that, since the engine is being kick-started, it can't start backwards without the rider knowing? 'Cause I have first-hand experience that it certainly CAN happen.
I'm not saying that it's impossible. I'm saying that for this to happen the stars have to come into perfect alignment.

The timing has to be just right, by accident since the key is sheared. That alone is a long shot. But I'm not doubting that it has happened to the people who have said so in this thread. Murphy's law at work, what ever can go wrong, will go wrong, at the worst possible time.

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Murphy's law at work, what ever can go wrong, will go wrong, at the worst possible time.
And the likelihood that an expensive part will break is directly proportional to the difficulty of accessing that part...👍

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