Modern Vespa

Hi friends, I hope this sees you well. I have been stuck trying to get into the 80 on 8's club and am now finally coming up for air.

I'm cooking the 2 smaller lighting coils & blowing bulbs due to excessive vibration (I think). It probably doesn't help that I overrev to 9k on a 60 year old scoot that shakes, rattles and rolls like a Big Joe Turner song.

My thought is to just switch to full wave and run the TrailTech Regulator/Rectifier with a small 1.2 Ah battery (kick start only). This will give me DC power to be able to run LED's and then thief some power to run a USB or GSF dyno.

The ignition coil is not part of this conversation and we are going to pretend that it does not exist for this discussion.

So watts the problem?
I pulled my stator and found something I didn't expect. Coils 1 & 3 are in parallel to each other and then in series with coils 2 & 4. WickedWeed drew a sweet schematic and it seems to line up with what I am seeing on my stator. Maybe this is how BGM is able to claim "more power" than stock. Here is the link to his MV thread BGM HP 2.5 Stator: Coils parallel. I also noticed that his stator coils are burned out similarly to mine.

I have found a video on Savage Scooters YT where they removed the grounds to the coils and then hooked up a wire to the coil where it did go to ground and called it good. This would give you a floating ground, but still leave coils 1 & 3 in parallel.

Possible Solutions: Coils 2 & 4 need to be replaced no matter what.
1) Replace damage coils with same thing, float ground and keep 1 & 3 in parallel with the rest in series (Savage Scooter solution)
2) Replace damage coils with same thing, float ground and have coils run in series (SLUK Solution)
3) Replace all coils with the same number of wraps per coil, float ground, and run in series
4) Replace all coils with the same number of wraps per coil, float ground, and run 1 & 2 and 3 & 4 in series respectively and then run the 1-2 combo in parallel with the 3-4 combo.

Questions:
-For a P-series (5 wire), how many turns are in the smaller coil? How many for the larger coil? What gauge? (According to Wicked Weed, it is 60 wraps for small and 70 wraps for big but I have not personally verified).

-What is the downside, if any, to running mismatched # of turns in series?

-Could running coils 1 & 3 in parallel be why I see every BGM stator on this forum with blackened coils 2 & 4?

-Does anyone have any idea how the BGM V4.5 DC Stator (8040N) has its coils arranged? I attempted to figure it out via the pics, but couldn't quite get there.

Background:
I suck at posting and maintain a presence here. Scoot as follows: VBA w/ a P187 engine, 7800rpm max power, 9000 overrev. BGM Stator 8025N (3 CDI wires, 1 black & 1 Blue for power) and stock flywheel. All AC w/ TrailTech AC Regulator. I'm using a BGM 9077011 wiring harness & switch and I have verified there is no rubbed wires in the usual places & grounds are attached.

Power requirements:
Max Power needed = 60W, Power needed* at idle = 30W. Breakdown below.

21W - LED Headlight (BA20d)
9W - LED tail/brake/pilot light (BA15S) @ 3w each
15W – Battery Charging
15W - USB
*I am ok with drawing on the battery at idle (1k rpm), because I rarely idle the bike.

Q & A:
What is fullwave, what are you talking about?
https://mastercircuits.blogspot.com/2011/06/half-wave-stator-to-full-wave.html

Do you have to have fullwave to have DC?
You do not, you just don't get the "full power" of the stator on the DC Side.

I want to know more about the science of stators, where should I go?
I would suggest checking out the Stators Demystified thread on AdvRider.

Links:
Scooter Lab UK (SLUK) article for converting stator to fullwave
Savage Scooters DC Conversion of BGM
Scootronics YT explaining the conversion if your coils are in series. This dude is a trouble shooting god.


Thank you for coming to my Ted Talk on why you should just buy a Vape ignition to begin with!!!

Personally, I'd buy a Ducati stator, float the ground and run a second blue wire. The coils should be in series on these stators (blue & black for power). I have done it many times and they work fine. Apparently these BGM stators were wrongly wired from their "no name", Asian manufacturer and SC didn't even care. There's no point trying to fix this crap...

Or as you said, buy a Vape ignition from the start...

there is so much right here i want to give you an award.

Yep, same here. Don't waste time rebuilding a fried aftermarket stator. A reliable static stator for a p crank and/or motor is the Ducati. It will last a long time even with the adjustments Safis mentioned above.

Ditto. Cooked an ET3 model BGM Pro 2 stator in a matter of weeks. Went Vape DC.

Well, huh...it's a small world...the guy who started the stator thread over on advrider is one of my friends. He builds rally navigation equipment (think Dakar and Sonora rally, ect). He and I ride dirtbikes together. He's a super smart, super cool guy.

First off, a tiny 1.2 ah battery seems pretty darn small. I would think you would want something closer to 5 ah?

"Rarely idle the bike"...as in every time you have to stop a sign or a stoplight, you rev up the engine?


Like everyone older said, either switch to a Ducati or a Vape. I've converted two of my 2005 PX's over to full wave DC (5 wire Ducati stators). I've also installed two DC VAPE kits in two other of my scooters. I think that since you have a performance engine, I'd lean more towards the variable DC VAPE stator kit.

Safis: Interesting to hear they were wired wrong
Rowdy: I'm a sucker for pain, so I may try to rebuild just to learn
MJRally: I saw your thread of a fried BGM a while back and that is in part of the reason I posted. There had to be a reason why all these BGM's are fried.
Whodat: Please tell Luke thank you and that it is still useful info even 17 years later!

Well lesson learned on the BGM stator. I may try to wire wrap it for the learning experience but then maybe buy a Ducati as a spare. Not going VAPE bc I am in too deep on current setup (kytronik, flywheel, CDI) and can repair for only $20 of wire. I think I priced out VAPE near $450 by the time you get the "dumb coil" and multi-curve CDI box.

1.2 Ah may be too low, I never actually did the math. Still I am going to try that or some other cheap battery first bc the VBA has no keyed ignition. So I am going to forget the lights often and drain the battery often and eventually kill it.

Whodat, I did see your PX DC thread. The pictures were extremely helpful for a friend I was helping as there is still almost no info out there for the swap.

17 year old thread...that means Luke wrote it when he was about 28-29 years old! I'll be sure to tell him thanks for you. Hopefully i see him next week. He has a VERY nice TIG welder, and i'm trying to pin him down to modify (fix?) my stainless JL pipe.

My PX DC conversion was a exercise in hair pulling. There was only a few smatterings of info out there, and none was for the US market 2005 PX150. It took a few weeks for me to 100% sort out the whole wiring conversion. It was WAY more challenging than a Stella DC conversion!

FYI, most of my riding is also highway...probably 90%-95% of the time any of my P200 powered scooters live at 60mph on a 4 lane highway for at least a 30 mile stretch. The other 5-10% of the time is at stop signs and traffic lights once i get off the hghway...idling.

Well... you just can't make this $hit up. It appears that the BGM stators are crap. They probably outsource them and the company that makes them in bulk has a lower quality standard. I encounter issues with my stators but I never cooked one like that, my problems on piano stators were simply old brittle and oxydized wiring and a lose rivet holding the stator plate but I never cooked one.

If anyone cares to watch a video there is a video from mista freak power on YouTube showing no significant gains on performance with upgraded stators. He tested a few and he believes that the stock ones performs well.

What I find attractive of the new style model stators is the power output and weight savings.