MOPED ARMY

Did you adjust your timing? Any air leaks?

Are you using a resistor type spark plug, and have you tried new ones?

It would be extremely helpful to hear the noise if you could record it somehow.

Can you run both a resistor boot and a resistor plug?

Each resistor , the cap or the plug , is about 5k ohms . Both would be about 10k ohms .

If I understand correctly , some CDIs require a 5k ohm resistor . Which ones , I don't know .

I would think that anymore than the minimum required resistance would detract from the quality of the spark .

I just don't have a phone mount on my bike and don't really want to try to hold a phone in my hand while riding 40mph on city streets, but I think an old phone case + duct tape may be a workable solution.

Put ignition back the way it was stock

Sounds like you need a stock coil.

Grabbed a recording, I wasn't able to capture it properly on the kickstand so there's some wind noise from riding, I ran a high pass filter to try to minimize the noise and uploaded both files in case one is easier to hear than the other. The best spots are probably about 6-7 minutes and 8-9 minutes, that's when I was able to maintain speed the longest.

Original

High Pass filtered

I have a trail tech tachometer (I don't really trust it though) and the bike seems to max out at around 7K RPMs at which the point the engine and the tach start freaking out. It feels like the engine is pulsing, like it wants to go higher but then pulls back, if you listen closely you can hear the engine noise kind of going in waves. I actually had a quick second when the bike broke through on the RPMs and got up near 45 but the tach was all over the place and it slowed back down to 40ish.

I tried a bunch of different throttle positions at the "top speed" and it seems to have no effect, when the throttle is wide open the engine sounds a bit deeper but overall acts exactly the same as when running in a lower throttle position at that speed/RPMs.

Hopefully this is helpful, if not I can try mounting my phone someplace else on the bike to get a clearer recording.

Thanks

My old stock coil is gone, If anyone know where I can get a legit stock coil in good condition (from what I understand there are a few different "OEM" ones and some of them suck) or has a reco for decent aftermarket/performance coil I'll give it a shot. I just don't want to spend a bunch of money ordering different coils in hopes that one will work. (edited)

If you go to the top of the page and click View Flat , it'll make your life easier . ;)

I ordered a used stock iskra coil from moped junkyard, will report back if it makes any difference.

did you fix an air leak then not re-jet? are you just jetted way rich to compensate for the air leak?

the spark plug resistor thing has nothing to do with it.

the cdi boxes changed around '99 or 2000 from un-restricted, to one with a restrictor at about 8k rpm. you can see it wiht a timing light, the spark will retard dramatically (like 20 degrees) when the restrictor kicks in.

there are several versions of restricted one-wire tomos cdi's that were stock and aftermarket replacement over the years, but most bikes don't hit the rev limiter, 8000 is pretty high unless you are kitted

I was too impatient when I got home to mess with the timing light, I just threw the new box on and went for a ride... huge huge improvement, the bike runs like it used to and fully revs out.

For the record and future reference this was the box that had a speed limiter and this coil is the one that I replaced it with and so far seems to not have any issues.

If that's the case , why do I get a stronger spark when not using any resistance ?

No CDI involved , of course .

Just for the record resistor plugs make the spark duration longer...

Borderline chaos in blowing up is the only way you reached top limit you could use the old three seashells thing you can adjust your mix you going to dress your timing or you add something...