Modern Vespa

I am stuck in a no start, plug gets wet and used to spark when I pulled it out then I cleaned it with some break clean and cleaned up the isolator a tad and then it stopped jumping the gap.

It will jump to the engine but not across the plug so I assume the plug is broken.

I am struggling to figure out what plug is supposed to be in there though. Looking online I have seen a few different NGK plugs that are claimed to be the correct one:

BPR7ES (what is in there now)
BR7ES
BP7HS
B6HS

So does anyone actually know what to use?

I belive the engine is pretty much stock configuration. Idle jet is a tiny bit richer than stock is all.

I discussed in another thread that my plug has a bit of a two face look. Most of it look golden and perfect but then a bit of it looks damaged and overheated. As I did not put this plug in, I don't know if that overheating stuff is the current tune or not. I've only had my PK for a month and a bit.

The manual specification calls for an NGK B6HS

The BPR7ES has a projected electrode AND the thread reach is 19mm vs 12.7 mm of the B6HS. They are not equivalents.

Yeah this is why I was confused, they are not even close to the same plug, yet I've seen both recommended. Even NGKs website isn't sure, it recommended both BPR7ES and B7HS iirc.

I'll get a B6HS and see how that runs come spring. Season is over for me and my Vespa is tucked away for winter storage now ❄️

Not looking forward to cleaning the ethanol gunk from the carb... Is there a carb bowl with a drain available anywhere? I haven't seen one, if it was metal I'd just drill and tap it but it's plastic

Hallo Bananasplit

I see from NGK coding chart that B7HS is for colder climate than B6HS, which could be a benefit to your swedish climate.

I have a piaggio pk xl75 and xl125 under the seat manual at home. When i get in will tell you what the plug supposed to be.

I have two PK 125 XL Elestart engines, they're basically P125ETS engines plus the starter. Both use long reach plugs, so B7ES or B8ES…

Seems like we are right back to the confusion

Both long and short plugs recommended here too!

Maybe it just doesn't matter that much?

Er… spark plug length matters.

The heat rating less so because it will run regardless, but the engine was designed with a specific rating in mind.

OK, i have a piaggio underseat manual for my PK75XL with the plug spec written for the PK125XL too, hopefully this clears it up. Champion n3c readily available on line and it looks to be a long reach. If you need anymore info from the manual, shout. Its in spanish but you can suss it out quite easy.

So then

My pk 75xl is an 8ES , took it out earlier as simply forgotten what's in it as laid it up for winter . The little scoot plug gets quite hot but then again 50mph standard is quite a lot of grunt for such a small capacity .