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NGK BM7F Spark Plug (6421)
Original price was: £6.89.£3.19Current price is: £3.19.
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NGK BM7F Spark Plug (Stock No. 6421)
The NGK BM7F is a reliable, non-resistor spark plug for many small engines. It delivers consistent ignition, easier cold starts, and steady idle. The heat range suits engines that run a bit hotter, helping reduce fouling in stop-start use.
Its nickel-alloy electrode with a copper core gives stable performance and long service life. A fixed solid terminal ensures a secure connection on engines that use a clip-on lead.
- Reliable starts and smooth running in everyday use
- Helps resist fouling in low-speed or short-run operation
- Durable construction for small-capacity engines
Note: This is a non-resistor plug. It may cause electrical interference on some vehicles with sensitive electronics.
| Part Number | BM7F |
| NGK Stock Number | 6421 |
| Part Category | 686 – Spark Plug |
| GTIN | 087295164211 |
| Thread Size | M14 x 1.25 |
| Reach (thread length) | 9.5 mm |
| Hex Size | 20.8 mm (13/16 in) |
| Seat Type | Flat gasket |
| Heat Range | 7 (NGK scale) |
| Resistor | No |
| Terminal | Solid |
| Electrode Material | Nickel alloy with copper core |
| Electrode Design | Standard |
| Factory Gap | 0.7 – 0.8 mm (check and adjust to your spec) |
Fitment guidance
Often used in small-capacity two-stroke and four-stroke engines found in scooters, mopeds, pit bikes, generators, and garden machinery. Always use the site’s vehicle lookup to confirm fitment, or check the Vehicle Fitment tab for full details.
The price displayed is for a single plug, please add the desired amount to your basket.
| Weight | 0.05 kg |
|---|---|
| Dimensions | 10 × 3 × 3 cm |
| Brand |
NGK-6421 Confirmed Fitment
Our team haven't provided any fitment data for this product yet, please get in touch or check back later!
Stock at Progressive Parts
Delivery timescales are given as estimates in good faith, but cannot be taken as precise or exact information. We highly advise against booking installation/workshop time or engaging in preparatory work until you've received and inspected the goods.
What do our stock statuses mean?
1+ IN STOCK in green stock is readily available in one of our warehouses for express delivery (at the time of viewing).
LOW STOCK in green means we're running low! 1 or 2 left on the shelf so act fast. Over evenings, weekends and bank holidays this stock can move quickly so please bear this in mind.
0 IN STOCK in blue means our primary warehouse does not have unallocated stock, but our UK partners do. Often these can be shipped quickly and efficiently. You'll be notified via the Track My Order page if further delays are unavoidable.
MADE TO ORDER in blue means we've partnered with a supplier which primarily makes their products to order. It's not on our shelf, but your order goes into production immediately.
0 IN STOCK in orange means everybody we work with is unfortunately out of stock. Stock is not available in the UK. The best course of action is to place an order to create an allocation from the next batch arriving.
OUT OF STOCK in red. This product is unavailable to order, for whatever reason we're unable to obtain stock or there is an issue with supply/lead times.
We're tuners too!
Our staff are car enthusiasts, we understand the need for speed... This includes getting your orders out the door as quickly and securely as possible!
In some instances, extended lead times are unavoidable. This is as labour-intensive and frustrating for us as it is for you, please know we are doing our best to facilitate your modification goals. Abuse of our staff or systems will not be tolerated.
Thank you, Team PP
In the words of the Vehicle Standards Agency (VCA), type approval provides "confirmation that production and samples of a design will meet specified performance standards".
For emissions components this encompasses noise, emissions and balanced back pressure, which have a strong influence on maintaining engine performance (power), and fuel efficiency. Type approval ensures that an aftermarket component will reach, or exceed the performance standard of the corresponding OE part.
Type-approval then, is a certain guarantee that an end user will receive a product of OE equivalent performance attributes.
Products on the Progressive Parts website that meet this approval will be clearly marked or labelled EC or ECE approved.