You may not think about your sparkplug often, but it’s down there; sparking a few thousand times per minute, igniting your fuel, chugging that piston back and forth. It’s one of hundreds of parts that must work flawlessly in unison to keep you and your scooter moving safely through traffic. It’s actually stupefying that scooters or cars, (or human bodies) work at all. Maybe it’s better not to think about it.
But we must think about it, and we must take good care of our scooters (and our cars, and our bodies) so they continue to serve us well for many years. So give that poor spark plug a break and check the color and the gap, and change it occasionally. Check your manual for the service interval for your model, or if you don’t ride all that much, just throw a new one in every year, they’re cheap.
Spark Plug color
That’s easy! It’s colored white, with a shiny silver part.
But when we talk about spark plug “color” we’re talking about the color and texture of the electrodes and insulation at the tip of the plug after it’s been running for a while. Inspecting the tip of the plug (especially through a scientifically-controlled series of “plug chops”) can tell you lots about your engine and help diagnose — or even reveal — problems with your engine, but that’s way outside the scope of this article. If you’re riding a stock scooter and it’s running alright, it’s just good to keep an eye on the condition of the plug when you’re cleaning, adjusting, or swapping your plug.
Using a plug tool to find and set your gap
(more about tools and units and checking/changing)
An NGK motorcycle plug ships with a .7-.8 mm gap, but it may be imprecisely gapped, or may be bumped in packing, shipping, or bouncing around in your glovebox for years, so check it and adjust it before installing. The chart below lists the specified gap for most common scooter models.
Some NGK plugs are specially-gapped at the factory, which is indicated by a dash and a number (in tenths of a millimiter — a BR7HS-10 has a 1mm gap). It’s fine to re-gap these pre-set plugs to meet your specs, it’s not any extra effort, since you’re always checking and setting the gap properly anyway. Never take a preset gap for granted.
The big “R” debate:
In recent years, mostly to reduce electrical interference — your iPhone, electronic components on your bike, your Cardo, etc— spark plug manufacturers have been transitioning to spark plugs with a built-in resistor. In NGK parlance, this adds an “R” as the second letter of the plug model, other manufacturers have different indicators.
NGK has quietly discontinued most of their non-resistor plugs in the ranges vintage scooterists want, so non-resistor plugs are getting harder to find — and more expensive — as stock runs out. If you go on scooter and motorcycle forums, you’ll find endless arguments whether it matters or not.
Most actual science-type people, argue that it doesn’t. While the resistor may adjust the character of the spark a tiny bit (allegedly a shorter but more focused spark), “R” plugs are designed match the specs of the original versions and really shouldn’t cause any problems. If they do cause a problem, buy a non-resistor plug on eBay for twice the price, and convince yourself it’s running better, like you do when you use really expensive 2-stroke oil and “premium” gas. We won’t point out that your fancy upgraded NGK plug cap you’ve been running since the nineties has a resistor in it anyway, and the 1/6 of a degree your timing is off — and all the pizza you’ve been eating lately — are the real issues.
If you have a modern scooter, “R” plugs are spec’ed anyway, so none of this matters. Huzzah!
https://www.ngk.com/ngk-spark-plug-numbering-systems
Cross-referencing
Carrying a spare
| Model | Gap | NGK | Champion | Denso | Marelli | Bosch | KLG | AC/Delco | Other |
|---|---|---|---|---|---|---|---|---|---|
| Vespa (modern/4-stroke) | |||||||||
| ET2 | BR9ES | RN2C | W27ESR | R41CXL | |||||
| most 125/150 models | .7–.8 mm .028–.031″ | CR8E, CR8EB | 8654,8654-2,RG94C | U24ESR-N | UR2CC | Autolite 4302 | |||
| GTS 300 ie | .7–.8 mm .028–.031″ | CR8EKB | RG 4 PHP | ||||||
| 300i HPE | .7–.8 mm .028–.031″ | MR7BI-8 | |||||||
| “M/C – PIAGGIO 2016, VESPA 2011-09” | ER9EHIX | (in NGK book) | |||||||
| Vespa (vintage) | |||||||||
| 1955-1965 Vespa 125 (VN, VNA, VNB, Allstate etc) | .6mm .023″ | B6HS† BR6HS | L82, L82C L85C, L86, L86C, QL86C | W20FS-U, W20FSR-U | CW 225 N-T or CW230 A-T | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | F70 or F75 | 43F | Autolite 414, 2655, Motorcraft AV3C |
| 1955-1965 Vespa 150 (VB, VBA, VBB, GL, etc) | .6mm .023″ | B6ES† BR6ES | NA8†, N5C | W20ES-U, W20ESR-U | CW 250 L-T or CW 240 B or CW 240G | W240 T2† | FE80 | ||
| 1955-1965 Vespa GS | .6mm .023″ | B6ES† BR6ES | NA8†, N5C | W20ES-U, W20ESR-U | |||||
| GS160 | .6mm .023″ | B6ES† BR6ES | NA8†, N5C | W20ES-U, W20ESR-U | F.E80 | ||||
| Smallframes (50R, etc) | .6mm .023″ | B6HS† BR6HS | L86C, QL86C | W20FS-U, W20FSR-U | CW7N, SNA7003-8 | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | F75 | 430F | Autolite 414, 2655, Motorcraft AV3C |
| Smallframes (Primavera, | .6mm .023″ | B7HS† BR7HS | L82C, RL82C | W22FS-U, W22FSR | CW7N | W240 T1† | 445Z | ||
| ET3 | .6mm .023″ | B7HS†BR7HS | L82C, RL82C | W22FS-U, W22FSR | CW7N AT | W240 T1† | 554Z | ||
| PK 50, 50S, 50S Elestart | .6mm.023″ | B6HS† BR6HS | L86C, QL86C | W20FS-U, W20FSR-U | CW7N, SNA7003-8 | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | F75 | 430Z | Autolite 414, 2655, Motorcraft AV3C |
| PK 125, 125S | .6mm .023″ | B6HS† BR6HS | L86C, QL86C | W20FS-U, W20FSR-U | CW7N, SNA7003-8 | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | F75 | 430F | Autolite 414, 2655, Motorcraft AV3C |
| PK80S automatica, MK125 S automatica | .6mm .023″ | B7HS†BR7HS | L82C, RL82C, 811, 821, 835 | W22FS-U, W22FSR | CW8N | W4A, W5A | 430Z, M42FF, MC42F | Autolite 413, 2636, 2653, 2654, 4092, 4093 | |
| P-series 150 or 125 (P125X P150X, etc) | .6mm .023″ | B6HS† BR6HS | L86C, QL86C | W20FS-U, W20FSR-U | CW 6N AT, SNA7003-8 | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | 43 F | Autolite 414, 2655, Motorcraft AV3C | |
| P-series 200 (P200E, etc) | .6mm .023″ | B6HS† BR6HS | NA8†,N5C | W20FS-U, W20FSR-U | CW 6N AT, SNA7003-8 | W7A, W225 T1†, 7996 WR7AC+†, W175T1, W175Z1 | F75 | 43 F | Autolite 414, 2655, Motorcraft AV3C |
| Lambretta | |||||||||
| LD | .6–.7mm .023–.028″ | B6HS† B7HS† B8HS† BR6HS BR7HS BR8HS | L86 L82C L78C | W20FS-U, W20FSR-U | |||||
| Series I,II,III, GP, J, and Luna ranges | B7ES† B8ES† B9ES† BR7ES BR8ES BR9ES | N4 N3 N2 | W22ES-U, W22ESR-U | CW240L | W225 T2† | Filso AVS 28-6 140 F-01 105†, Filso C12128/1† | |||
| Piaggio | |||||||||
| BV200 | CR8E | 8654, 8654-2, RG94C | U24ESR-N | UR2CC | |||||
| BV250, BV500 | CR7E, CR7EK | U22ESR-N, U22ETR | UR3CC | Autolite 4578 | |||||
| BV500 | CR7E, CR7EK | U22ESR-N, U22ETR | UR3CC | Autolite 4578 | |||||
| Liberty 50 C | RGN2C | ||||||||
| Liberty 125-400 | CR7EB | RG6YC | |||||||
| MP3-250, 400, 500 | CR7E, CR7EK | U22ESR-N, U22ETR | UR3CC | Autolite 4578 | |||||
| Typhoon | BR8ES | W24ESR | |||||||
| X9 | CR7E, CR7EK | U22ESR-N, U22ETR | UR3CC | Autolite 4578 | |||||
| Genuine | |||||||||
| Kymco | |||||||||
| Agility 50 4T, 125 | .6–.7mm .024–.028″ | CR7HSA | U22FSR-U, UR3AC , UR5 | Autolite 4203 | |||||
| AK500 | .7–.8 mm .028–.031″ | CR7E | U22ESR-N | UR3CC | Autolite 4578 | ||||
| Bet&Win 150, 250 | DPR7EA-9 | X22EPR-U9 | |||||||
| Cobra 50/Top Bou | BR6HSA | W20FR-L | |||||||
| CV3 | .7–.8 mm .028–.031″ | CR7E | U22ESR-N | UR3CC | Autolite 4578 | ||||
| Grand Vista | DPR7EA-9 | X22EPR-U9 | |||||||
| Like 50i | .7–.8 mm .028–.031″ | CR8E | 8654, 8654-2, RG94C | U24ESR-N, U20FSR-U | UR2CC | ||||
| Like 150i | .7–.8 mm .028–.031″ | CR7HSA, CR6HSA | U22FSR-U, UR3AC , UR5 | Autolite 4203 | |||||
| People 50 2T | .6–.7mm .024–.028″ | BR8HSA | W24FR-L | ||||||
| People S50, S125, 150, S200 | .6–.7mm .024–.028″ | CR7HSA | RZ96C | U22FSR-U, UR3AC , UR5 | Autolite 4203 | ||||
| People 250, S250 | .8–.9 mm.031–.354″ | DPR7EA-9 | RA8YC | X22EPR-U9 | |||||
| Spade 150 | CR8E | 8654, 8654-2, RG94C | U24ESR-N | UR2CC | |||||
| Autolite 4203 | .6–.7mm .024–.028″ | CR7HSA | U22FSR-U, UR3AC , UR5 | Autolite 4203 | |||||
| Super9 LC, AC | BR6HSA | W20FR-L | |||||||
| Vitality50 4T | CR7HSA | U22FSR-U, UR3AC , UR5 | Autolite 4203 | ||||||
| Venox 250 | CR8E | 8654,8654-2,RG94C | U24ESR-N | UR2CC | |||||
| Xciting 250, 250Ri, 500, 500Ri | .8–.9 mm.031–.354″ | DPR7EA-9 | RA8YC | X22EPR-U9 | |||||
| X-Town 300 | .8–.9 mm.031–.354″ | DPR6EA-9 | RA8YC | X22EPR-U9 | |||||
| ZX50 | BR8HSA | W24FR-L | |||||||
bold indicates plugs specified in original service manuals
all other plugs are derived from modern cross-reference charts or expert recommendations
† indicates defunct manufacturer or product
italic indicates alternate plugs recommended for tuned engines or certain situations
color code “resistor” indications?
Heat values
The Vespa Club of Chicago is providing this information as a free resource based on our research and experience, but makes no guarantee regarding the technical or editorial accuracy of the information presented above. Please consult your manuals, dealer, and other sources to make sure you’re using the correct plug and gap, and take into account any modifications or changes made for regional markets.