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Discussion Starter #21
Yeah, needle was going to be first hit after air leaks considering it starts at mid throttle. The nice thing about the VM is it's super easy to make adjustments, especially on a single.
 

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imho if it had an intake vacuum leak that should in theory make it a bitch to start and run away or not drop to idle quickly. Assuming everything else is well sorted, I'm optimistic that you can fix the problem you describe with a quick and easy adjustment to the needle position. At the very least it will determine if the issue is a lean or rich carburetor setting.
 

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Discussion Starter #23
I hope you are right. This bike has fought me tooth and nail up until now, and I think it's finally going the right direction. In fact, it's exactly the reason you guys preach to buy a better bike up front and save TONS of money and frustration. Sometimes it's enjoyable to tinker on stuff like this, and sometimes it's just a frickin nightmare. This one got way too comfortable in the nightmare zone. I'd do it all over again though and I know that doesn't make any sense.
 

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Discussion Starter #27
Only Harley I've worked on was a 72 Ironhead and it had points. I'll never own another and it wasn't because of the ignition.

 

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Discussion Starter #28
Timing was advanced too far. Reset it, and from what little I have been able to run it down the road, the flat spot feels like its gone. Still a little popping on decel, but I still think that's related to the hole I found. I'll get after it again in the daylight tomorrow and get another test run or two in.
 

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Discussion Starter #29
I've been wrestling with this bike for a week now checking timing, jetting, plug, fuel flow, points, condenser, etc. Everything. Still had a weird break in power mid throttle that eventually just got to the point it was just backfiring and timing seemed way off without the points plate moving.

Finally pulled the flywheel to find a sheered woodruff key and a shady source coil connection. I'm hoping once the replacements are in it will finally run properly.











 

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Yup, that would do it :|
I had a riding mower do that last year. I made a new key for it out of a piece of scrap steel :D
The coil wires are insulated with varnish, if you're going to MacGuyver it; raid your ol lady's cosmetic supplies and coat the damaged wire with 'hard as nails' nail polish first ;)
 

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Discussion Starter #31
I've got a nicer source/lighting coil and flywheel on the way as well as a new woodruff key. I'm trying to do it "right" once and get back to riding. I'll keep the old coils and probably send it off to be rewound as a spare.
 

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That would work too.

btw: if you don't have hard as nails you can also use plumbers teflon tape.
Just incase it turns into an Apollo 13 mission ;)
 

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Discussion Starter #35
I thought you were pulling my leg on the offset key, but it appears there are some available. None specific to the sr/xt/tt 500 models that I could find though. I do know that sheared keys are common if the flywheel isn't torqued properly, and this looks like it's ready to let go from what I see.
 

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The plot thickens :| Clean it up and put it under your stereo microscope :) If there's a number stamped on it it's definitely an intentionally offset keyway.
BTW: what's it made out of, it almost looks like it's brass in the photo. A brass key would normally be installed in something where you wanted the key to fail before doing damage to steel parts, like on a metal turning lathe or a propeller. But a lathe or propeller would never need an offset key, offset keys are normally used on motors where you can't easily adjust the ignition timing any other way, like a B&S go-kart engine.

lol looks like your motorcycle was either modified by a machinist, a sailor, a go-kart racer or a mechanical failure.
 

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I thought you were pulling my leg on the offset key, but it appears there are some available.
Offset keys are a common way to dial in cam timing on older Ducatis (and a whole bunch of other things too I'm sure). I don't think an engine could do that by itself, when the key let go I'd think it would let go all the way, not shift like that.

EDIT: Actually IMHO there's no way it could fail like that. In order to move the two faces it'd have to shear in the middle.

EDITED EDIT: So... why the offset key? Wild ass guess aka I'm resisting doing actual work for as long as possible today so let me ramble on about things I know little about... You said the timing was way off? I'm guessing this bike runs without a battery? My 160 is like that, and you have to time the flywheel electrickery bits along with the points to get it to run right. So... if the ignition timing was off on purpose, this could have been a way to keep the electrickery in synch with the ignition? Just a guess or three..
 

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Discussion Starter #38
One thing I know for sure is that it went from somewhat running, to virtually impossible to get past idle shooting flames out the exhaust at the flick of a switch. I feel like it started to let go but just didn't sheer off all the way, but looking at the key I can see why it also might have been offset. The nut to the flywheel wasn't loose, but it certainly didn't feel as tight as I would expect it to be.

The key feels almost like a lead or pot metal, but that's just an uneducated guess.

I'm just hoping that when the new parts get in, I can get this beast on the road reliably.
 

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;) I bet the replacement key you have on order is not offset.

& It definitely spun and flopped around on the tapered shaft at some point in its life.


btw: was the key inserted in the direction of advancing the timing? or retarding the ignition as it would more likely be after being sheared?
 
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