Modern BSA electrical systems demystified.

Body Control Module and Can-bus

Most people are aware of the Engine Control Unit (ECU), but think of the BCM as the central nervous system for many of your bike's electrical functions. It's a sophisticated electronic control unit that manages and monitors various systems beyond just the engine and transmission. While the Engine Control Unit (ECU) handles the powertrain, the BCM takes care of the "body" of the bike

The Body Control Module (BDM) provides the supply to the LED lamps of all 4 turn indicators, motorcycle rear lamps like tail lamp, stop lamp, number plate lamp and the associated indication lamps.

The BDM also maintains the blinking rate of turn indicators upon receiving a signal from the turn indicator switches and hazard switch.

The signals used are derived from an industry standard signalling protocol Can-bus, and is how the BCM communicates with all these different components efficiently.

CAN-bus (Controller Area Network bus)

Instead of having a separate wire for every single signal, which would be a massive, heavy, and complex wiring loom, CAN-bus uses a network that allows multiple electronic control units (like the BCM, ECU, ABS module, etc.) to share information using just a few wires.
Benefits of CAN-bus:
• Reduced Wiring Complexity: Fewer wires mean less weight and easier manufacturing.
• Enhanced Reliability: Fewer connections mean fewer points of failure.
• Faster Communication: Data can be shared quickly and efficiently between modules.
• Improved Diagnostics: Technicians can connect to the network to retrieve diagnostic information from all connected modules.
• Scalability: Easier to add new features and modules to the network.

Understanding the BCM and CAN-bus helps you appreciate the engineering that goes into modern motorcycles. It explains why some electrical modifications require careful consideration and why specialised diagnostic tools are often needed. It's all about making your ride smarter, safer, and more reliable.
#LumpyCarbs

E10 - 5 Fuel & Storage – What You Need to Know (Motorcycles)

If your bike is sitting for a while, E10 doesn’t stay “fresh” for long.

How long is E10 safe in a modern bike?

➡️ Around 4–8 weeks before it starts to degrade.

After that, starting issues and rough running become more likely.

Storage comparison:

• E10 (10% ethanol): ~1–2 months

• E5 (5% ethanol): ~2–3 months

• Ethanol-free / Super+: 4–6 months+

Why E10 goes bad quicker:

• Ethanol absorbs moisture

• Can cause corrosion in tanks and lines

• Fuel loses volatility → harder starting

If parking your bike for winter or longer:

✔ Fill the tank almost full

✔ Add a fuel stabilizer (Millers, Motul, STA-BIL etc.)

✔ Run the engine for 2–3 minutes to circulate treated fuel

Pro tip: If storing for months, switch to E5 or ethanol-free before parking it.

Ride it often, keep it fresh 👊🏍️

 

FIRST EVER BSA ADVENTURE BIKE REVEALED AT EICMA

BSA has unveiled its fourth bike at EICMA, the new BSA Thunderbolt. A striking combination of stunning design and the latest rider technology that this segment demands. The original Thunderbolt delivered touring and off-road capability, and now the legacy of the last ever bike to roll off the Birmingham production line in 1972 is handed over to the first adventure bike from BSA. The new BSA Thunderbolt ready for the new generation of riders – a reimagined icon.

BSA’s return continues at pace with a new model – just three months after launching the BSA Bantam 350 and BSA Scrambler 650
BSA Thunderbolt is a nod to the past and an advance into the future with on and off-road capabilities engineered to go the distance
Technical features traction control, three ABS modes, USD forks, mono rear shock and a slip and assist clutch
High ground clearance, reinforced bash plate and integrated exoskeleton offer off-road protection and durability
Powered by a 334cc single cylinder, DOHC, liquid-cooled engine, Euro 5+ compliant with a large 15.5 litre fuel tank
Ergonomic design offering adjustable front windshield and instrument console, turn-by-turn navigation, Bluetooth connectivity and USB charging

BSA is ready to take on the adventure market with the reveal of the new BSA Thunderbolt. The brand’s fourth bike, set to hit the market mid-2026, will thrive on every kind of terrain, from city streets to gravel tracks, through rain, mud, and dust. The modern BSA Thunderbolt is for weekday commutes and weekend adventures, both near and far.

Featuring rugged aesthetics including a rally-style beak and rear rack, the newest model is geared up for full throttle escapades with premium traction control and three ABS modes (Rain, Road, Off-Road). Additionally it offers a preload adjustable mono shock rear suspension, slip and assist clutch, and an upswept exhaust for better water wading capabilities.

When standing on the pegs is the best way to tackle the terrain, the adjustable front windscreen and instrument console ensures no compromises. The low seat height, lightweight design and wide handlebars delivers class-leading manoeuvrability for all riders, with added assurance of high ground clearance, a reinforced bash plate, exoskeleton frame and knuckle guards for protection, if needed.

Promising power and efficiency, the high torque Euro 5+ compliant 334cc liquid-cooled DOHC single cylinder engine, provides compelling performance with a six-speed gearbox and a large fuel tank perfect for longer journeys. Whilst additional space allows for a pillion and luggage – encouraging riders to go further and explore for longer.
#bsathunderbolt350 #LumpyCarbs

 🚀 Fastest-Growing Motorcycle Segments: 2025 Market Shakers & Movers 

Here’s a quick, insight-packed breakdown of which motorcycle segments are revving up global growth — both in engine size and style.

1. Mid-Displacement (200–400 cc)

Fastest-growing engine range globally (≈12% CAGR through 2030). Riders are upgrading from entry-level 100–150 cc commuters into this sweet spot of performance and affordability.

Hot styles: roadsters, compact adventure bikes, small sport-tourers.
Markets: Exploding in India, Southeast Asia, Latin America.

 2. Premium Mid-Heavy (601–800 cc Adventure/Touring)

Strong CAGR in the premium segment, especially adventure/touring machines. Buyers want versatile, long-range comfort and power without going full superbike.

Hot styles: ADV tourers, dual-purpose, premium cruisers.
Markets: Europe, USA, Australia.

3. Adventure / Dual-Sport Style (All Sizes)

Fastest-growing style worldwide (~10% CAGR). Combines commuting, touring, and off-road versatility.

Hot across all sizes — from 250 cc entry ADV to 1200 cc adventure beasts.
The ‘do-everything’ segment riders love.

✅ Key Takeaways

200–400 cc adventure/road-touring bikes = **fastest-growing globally**.
601–800 cc adventure/touring = **fastest-growing premium category**.

Adventure/dual-purpose style = **#1 rising motorcycle type worldwide**

💬 Want to catch the next wave? Look where performance meets practicality — that’s where the market’s headed.

#LumpyCarbs 

Thinking of fitting an LED bulb or full headlight on your bike?

Some riders are swapping their halogen bulbs for LEDs days — brighter light, less power draw, modern look. But have a little caution to stay on the UK legal side
A recent news report notes that the Driver and Vehicle Standards Agency (DVSA) is stepping up actions against the sale of illegal retrofit headlamp bulbs and warns of fines up to £1,000** for sellers of illegal bulbs.

LED bulb swaps

 Yes, you can use an LED bulb for your main/dip beam, but only if it meets the right standards.
Since 2021, the MOT rules changed — you won’t automatically fail just for having an LED bulb in a halogen housing. The key things are:
The beam pattern and aim must be correct (no glare to oncoming traffic).
The light colour must be white or yellow.
The lamp must work properly on dip and main beam.
But…
Not all LED kits are road-legal. If your bulb or headlight unit is marked “off-road use only” or produces a messy beam pattern, that can get you pulled or fail an MOT.
Best advice:
Buy LEDs that are specifically marked as road legal or E-approved.
After fitting, check your beam pattern on a wall — make sure it’s not blinding oncoming drivers.
Mention it at your next MOT — if the beam pattern, colour and aim are fine, you should pass.
The short version: LEDs can be legal on motorcycles in the UK — but only if fitted and aligned correctly.

Complete LED headlight assemblies

If you’re replacing the whole headlight unit with a complete LED assembly, it’s much easier to stay on the right side of the law.

It’s legal if:

The headlight is E-marked (or UKCA approved).
It’s designed for road use (not “off-road/show use only”).
The beam pattern, colour, and aim meet MOT standards.
These are fully tested for output and safety — so an E-approved unit fitted and aimed properly is good to go.

Units with built-in DRLs & indicators

This is where many get caught out. Some fancy LED assemblies include daytime running lights and integrated turn signals.
Legal only if each function is type-approved and correctly marked (look for E-codes like “RL” for DRL, “1a” for indicators, “DC” for LED headlamp, etc.).
Not legal if:
There are no E-marks, or
The DRL doesn’t dim when the headlight’s on, or
The indicators don’t meet spacing/brightness rules (at least 240mm apart at the front).
If it’s unmarked or says “for show use only,” it’s not road-legal or MOT-safe. And if there are simply no CE markings - you are taking a risk.

If you have done a legal swap and it works well - please share your source and details.

** https://www.theguardian.com/.../uk-steps-up-review-of...

BSA Scrambler 650 mini review 

With only a few hours to test the Scrambler 650, I headed off road and crawled up a muddy lane. An hour later I can tell you through clenched teeth and back pain, it’s a lot more capable than I am. I would not have even attempted this track on my Gold Star and it certainly proved to me that the Scrambler is a very different bike. - And I’m really not skilled enough to match its capabilities. My first test ride was in the summer, and in sunshine on dry roads and a bit of travel across a building site. This time it was wet leaves on greasy roads and a sticky muddy lane.

As I’d noticed before, that large rear sprocket really does affect the gearing compared to my Gold Star 650. There is also a significant difference in handling with a 19-inch front wheel compared to the GS 18-inch, mainly this comes down for the need to satisfy a hybrid riding purpose. The geometry, tire profile and suspension all feel quite different, also the higher riding position and wider bars. The larger diameter front wheel means slower steering with stability at speed but it takes slightly more effort to initiate turns, and then it drops into them more urgently. Hard to explain really. The larger circumference does improve things over bumps, rocks, and potholes. The tyres however did clog up on wet mud very quickly but gave me plenty of confidence on tarmac. Gravel was fine too.

Geometry changes for the Scrambler 650 seem to work very well. Rake and trail are sorted with taller springs and steeper rake. I’m ill equipped to expertly express off road opinion these days with stiff creaking joints and an aversion  to pain. However, I stayed upright even after a couple of hair raising rear slides and an unexpected puddle much deeper than I was anticipating.

Although the seat height and peg positioning are all higher compared to the gold star, I never felt unbalanced and my feet can still just about flat foot when down. It is a very different riding style to what I’m used to, and as with my summer experience, it is still a comfortable motorcycle to ride on the road and in the right hands it will, I’m sure, be able to satisfy a competent green lane enthusiast.

I look forward to an opportunity to spend more time with the scrambler sometime in the future as it certainly has some really appealing qualities that I would like to explore further.

#bsascrambler650 #LumpyCarbs

The BSA Bantam 350 has a secret weapon……..

It is almost time for me to do the impossible and give back my BSA Bantam 350 press bike. With a day to go, “Yellow Peril” has travelled 400 thrilling miles. I’ve met up and ridden out with retro, modern and classic bike owners. I’ve travelled on country lane bimbles, and belted 40+ miles down the motorway and back for enjoyable ride-outs with other Bantams owners. I’ve met with a friend to compare to his RE Hunter close-up, and I’ve even looked under the panels to check servicing and quality considerations.
Today I cleaned it, for me that’s another test as you go over the whole bike with eyes and fingers. And finally, I’ve sieved through a bunch of YouTube videos, some laborious and full of platitudes, some pretty good and honest. It’s hard to find a harsh word anywhere, and all the owners I’ve met are delighted.

How do I sum things up personally?

Well, I can’t fault it, I can see ways to improve it but not fault it. Yes, the mirrors have a little buzzing over 50, the engine is a monotonous drone at 7,000 revs / 70 mph and a faint vibration can be felt through in the footrests. Lights are OKish, instruments are OK too, it’s easy to see the indicator flashing but far too many tiny LCD legends that only a teenage web developer with 20/20 vision would think is a suitable font. (All manufacturers please take note, and web developers too). There are also missing things, like a USB socket and …….. well…… absolutely nothing that that can’t be and will be addressed by OEM and aftermarket accessories. At it’s price point, it’s perfectly acceptable to expect to embellish it, and let’s be honest, most of us relish that little task of personalisation.
As I have passed the run-in period, I can tell you it pulls all the way up to the rev limiter at 8000 revs and growls like an angry hornet. It farts wonderfully on overrun and anyone who says that’s bad mapping, I don’t want it fixed. There are no flat spots, the engine never overheats in my er…. spirited riding, but the radiator fan does tell me off. The gearbox is so slick I worry it’s got to let me down; it can’t be that good on a bike of this value, can it? The wide bars, the relaxed steering rake, the seating position, and the comfy bench seat, all fit me nicely. Aesthetically, it is also very pleasing, - I’m kidding it is bloomin’ gorgeous! Especially in the eye-popping yellow. It’s not a small bike and having the same size tires as the Gold Star is one of those secrets, it results in a smooth, refined ride. The suspension is good too and so are the tyres, but everyone seems to have their own opinions on this, maybe I’m just used to 1960 classic bikes and find this space aged by comparison.

I was getting 67 mpg, probably my own fault, like I said, I was pushing the bike all the time, always on the legal limits. Over Dartmoor the limit is 40 mph and tempered further by sheep, ponies, and cattle. In these conditions it tests how nicely the engine is tuned and the torque surprises me on what I consider a tiny engine, especially with 6 gears. The little gear indicator is useful when bimbling along as in 4th or 5th because it is easy to drop the revs ridiculously low and be surprised when it wont pick up, and I’m talking ridiculously low, 6th is good from mid 30s and 5th on most hills, but drop to 30 and you do need 4th. 

There is a notorious steep dual carriageway section known as Telegraph Hill on the A38, 1.6km with a gradient ranging from 5-10%, the perfect test for the Bantam, the Gold Star of course breezes up at 70mph without a sweat. The Bantam sustains 65 mph in 6th, very impressive.

So back to my title claim “the Bantam 350 has a secret weapon”. And indeed, it does, it explains how it has so quickly captured the heart of riders. – Its hidden in Anupam Thareja has tag line “True Brit, Indian Grit”. The Bantam is not a timid version 1 motorcycle, it’s a reawakening of an ethos, a peoples bike, priced to be accessible, attractive to all ages, rugged in construction and fun, - lots of fun. It is also not a version 1 motorcycle because its tried and tested in its native country in the lineage of the Jawa and tough little Yedi bikes, couple that to a willingness to enlist UK engineering design expertise and performance that punches above its weight, - it was always going to be a winner, and that’s the secret……..
Please BSA Motorcycles UK can I have one for Xmas?
#LumpyCarbs personal views.