HONDA CRF300L / CRF300 RALLY – SSS 350cc BIG BORE PERFORMANCE KIT. INTRODUCTORY PRICING / BLACK FRIDAY SALE. ONLY 6X KITS AVAILABLE AT THIS PRICE. NO EXCEPTIONS.
AUSTRALIAN DEVELOPED • PRECISION MACHINED • DYNO TESTED
35+ REAR-WHEEL HORSEPOWER!
MORE THAN 52% INCREASE IN PEAK REAR-WHEEL HORSEPOWER OVER STANDARD!
INTRODUCTORY KIT PRICE – $1,990 AUD
SPECIAL RIDE-IN, RIDE-OUT PACKAGE – $2,990 AUD
SIX-MONTH LIMITED WARRANTY INCLUDED WITH SSS MOTORCYCLES INSTALLATION
BRAND-NEW CRF300L & CRF300 RALLY MOTORCYCLES ALSO AVAILABLE WITH OUR 350cc CONVERSION – AUSTRALIA-WIDE DELIVERY!
PRE-ORDER NOW | APPROXIMATELY 2–3 WEEKS FOR KIT DELIVERY
THE NEXT LEVEL OF HONDA CRF300 PERFORMANCE HAS ARRIVED!
MORE CAPACITY. MORE TORQUE. MORE HORSEPOWER.
Introducing the all-new SSS MOTORCYCLES 350cc Big Bore Performance Kit for the Honda CRF300L and CRF300 Rally.
Following extensive engineering, precision machining, DYNO development and real-world testing since January 2026, we are proud to release our most powerful CRF300 performance package to date.
Our development motorcycle has achieved over 35 horsepower at the rear wheel, compared with approximately 23 horsepower in standard configuration.
That's a gain of more than 12 rear-wheel horsepower, representing an increase of over 52% in peak horsepower.
And here's what makes this achievement particularly impressive:
WE HAVE RETAINED THE ORIGINAL HONDA CAMSHAFTS, STANDARD VALVE SIZES AND UNMODIFIED CYLINDER HEAD PORTS!
Rather than relying on extreme internal engine modifications, we have focused on increasing displacement, optimising airflow and developing a dedicated ECU calibration to deliver a substantial improvement in usable engine performance.
The result is a serious performance upgrade for riders who want considerably more from their CRF300L or CRF300 Rally.
PROVEN DYNO PERFORMANCE
THE EVOLUTION OF SSS CRF300 PERFORMANCE
Our development program has continued to push the capabilities of the Honda CRF300 engine platform.
ENGINE CONFIGURATION| REAR-WHEEL HP
Standard Honda CRF300L – 286cc| Approx. 23 HP
Standard engine + SSS ECU reflash| Approx. 25 HP
ECU, intake and exhaust upgrades| Up to 27.5 HP
SSS 301cc Big Bore Kit| Approx. 30 HP
SSS 325cc Big Bore Kit| Approx. 32 HP
SSS 350cc BIG BORE KIT| 35+ HP
OVER 35 REAR-WHEEL HORSEPOWER – ACHIEVED ON OUR IN-HOUSE DYNOJET 250i DYNO!
All figures represent approximate peak rear-wheel horsepower achieved during our testing with the relevant supporting modifications and ECU calibrations.
Individual motorcycle results may vary depending on configuration, mechanical condition and operating conditions.
AUSTRALIAN ENGINEERING & IN-HOUSE PRECISION MACHINING
DEVELOPED IN AUSTRALIA. PRECISION FINISHED IN AUSTRALIA.
At SSS MOTORCYCLES, we believe the quality of a performance engine conversion comes down to much more than simply increasing cylinder capacity.
The cast cylinder and piston used in our 350cc conversion are manufactured in Southeast Asia.
However, the manufacturing process does not end there.
ALL FINAL PRECISION MACHINING AND CRITICAL TOLERANCE CHECKS ARE CARRIED OUT IN-HOUSE AT THE SSS MOTORCYCLES MACHINE SHOP IN TAMWORTH, NSW, AUSTRALIA.
This allows us to maintain direct control over:
- Final precision machining operations
- Critical component dimensions and tolerances
- Cylinder and piston preparation
- Component inspection and quality control
- Consistency of our finished performance packages
We do not simply receive a finished cylinder and piston assembly and place it into a box.
Our final machining and inspection processes form an important part of the development and preparation of our 350cc conversion.
Combined with our in-house ECU calibration development, Dynojet 250i DYNO testing and real-world evaluation, this allows us to maintain direct oversight of the critical finishing processes.
CAST CYLINDER & PISTON MANUFACTURED IN SOUTHEAST ASIA.
FINAL PRECISION MACHINING & TOLERANCE VERIFICATION PERFORMED IN AUSTRALIA.
PERFORMANCE DEVELOPMENT & DYNO TESTING BY SSS MOTORCYCLES.
WHAT'S INCLUDED IN THE COMPLETE 350cc PERFORMANCE KIT?
Our complete 350cc conversion package includes:
1. 350cc Cylinder & Piston Assembly
Purpose-developed big bore cylinder and piston assembly, with final precision machining and tolerance verification performed in-house at SSS MOTORCYCLES.
2. Complete Top-End Gasket Set
Required top-end gaskets supplied for installation of the conversion.
3. SSS Velocity Intake Stack
Designed to improve intake airflow and complement our dedicated ECU calibration.
4. SSS Vented Airbox Lid
Improved airflow capacity to support the increased engine displacement and performance requirements.
5. Secondary Airbox Snorkel
Additional intake modification included in our recommended configuration.
6. SSS Performance ECU
Supplied with our dedicated 350cc calibration developed through extensive DYNO testing and real-world evaluation.
NO CYLINDER OR ECU EXCHANGE REQUIRED!
Both the cylinder assembly and ECU are supplied as outright purchases with the complete kit.
Customers who already own compatible approved components may qualify for the deductions detailed further below.
REQUIRED SUPPORTING MODIFICATIONS
To achieve the advertised performance figures, the motorcycle must be equipped with suitable intake and exhaust modifications.
HIGH-FLOW AIR CLEANER
We recommend a suitable high-flow air filter from:
- Uni Filter
- Twin Air
PERFORMANCE EXHAUST SYSTEM
YOSHIMURA FULL EXHAUST SYSTEM
Our development motorcycle achieved over 35 rear-wheel horsepower using a Yoshimura full exhaust system, our recommended intake modifications and dedicated 350cc ECU calibration.
SSS MOTORCYCLES MEGABOMB HEADER
Our SSS Megabomb header has demonstrated particularly strong mid-range performance when combined with the 350cc conversion.
Peak top-end horsepower may differ depending on the exhaust configuration.
PLEASE NOTE: Performance exhaust systems and high-flow air filters are additional purchases and are not included in the standard kit or introductory ride-in, ride-out price unless expressly specified.
TECHNICAL SPECIFICATIONS
ENGINE CAPACITY: Approximately 350cc
CAMSHAFTS: Original Honda camshafts retained
VALVES: Original Honda valve sizes retained
CYLINDER HEAD: Standard, unmodified ports
COMPRESSION: Moderate compression configuration
FUEL: Designed for unleaded petrol rated 91 RON or higher
ECU: Dedicated SSS MOTORCYCLES 350cc calibration
CYLINDER DESIGN: Increased cooling water jacket capacity and thicker cast-iron sleeve
FINAL MACHINING: In-house at SSS MOTORCYCLES, Tamworth, NSW
DYNO DEVELOPMENT: In-house Dynojet 250i
Our goal has been to produce a strong, usable engine package with substantial improvements in horsepower and torque, rather than simply chasing the highest possible peak horsepower figure.
IMPORTANT – APPROVED ENGINE CONFIGURATION ONLY
PLEASE READ BEFORE PURCHASING
The SSS MOTORCYCLES 350cc Big Bore Performance Kit has been developed and calibrated for a specific engine configuration.
WE DO NOT OFFER ECU CALIBRATIONS, DEVELOPMENT OR TECHNICAL SUPPORT FOR ADDITIONAL INTERNAL ENGINE MODIFICATIONS TO THIS PACKAGE.
Unsupported modifications include:
- Aftermarket or performance camshafts
- Ported or modified cylinder heads
- Oversized valves
- Increased compression beyond our supplied configuration
- Alternative pistons or combustion chamber modifications
- Additional displacement increases
- Other internal engine modifications outside our approved specifications
Our ECU calibration has been developed specifically for the components and engine configuration recommended by SSS MOTORCYCLES.
Additional internal engine modifications may significantly alter the engine's fuel requirements, ignition requirements, operating characteristics and mechanical reliability.
CUSTOM ENGINE CALIBRATIONS FOR MODIFIED VERSIONS OF THIS 350cc PACKAGE ARE NOT AVAILABLE.
Approved supporting intake and exhaust modifications remain permitted as outlined in this listing.
ENGINE COOLING & DURABILITY DEVELOPMENT
The 350cc cylinder incorporates an increased cooling water jacket and thicker cast-iron sleeve.
Under our current development and testing conditions, we are satisfied with the cooling capabilities of the original Honda single-radiator arrangement.
Additional cooling requirements may be considered during future development if necessary.
CLUTCH & GEARBOX LONGEVITY
We are continuing to monitor clutch and gearbox durability under the increased horsepower and torque produced by this conversion.
Further performance development will not proceed until we are satisfied with the durability of the current configuration.
Potential future upgrades, including higher-compression configurations, performance camshafts and adjustable camshaft sprockets, may be investigated during the second or third quarter of 2027.
THESE FUTURE MODIFICATIONS ARE NOT PART OF, OR SUPPORTED FOR, THE CURRENT 350cc PACKAGE.
INTRODUCTORY PRICING – THREE PURCHASE OPTIONS
OPTION 1 – COMPLETE 350cc BIG BORE KIT
$1,990 AUD
KIT ONLY – ARRANGE YOUR OWN INSTALLATION
INTRODUCTORY PRICING / BLACK FRIDAY SALE. ONLY 6X KITS AVAILABLE AT THIS PRICE. NO EXCEPTIONS.
This option is ideal for customers who prefer to have their engine conversion installed by their own trusted motorcycle mechanic or workshop.
The complete 350cc kit is supplied with our dedicated ECU calibration and the components detailed in this listing.
SAVE MONEY IF YOU ALREADY OWN APPROVED COMPONENTS!
We understand that many existing SSS MOTORCYCLES customers have already purchased some of our performance components.
For this reason, we offer the following deductions:
EXISTING COMPONENT / OPTION| DEDUCTION
Supply your existing compatible ECU for reflashing| –$150
Already own our approved SSS Velocity Intake Stack purchased from our website| –$150
Secondary airbox snorkel not required| –$35
Already own a compatible SSS vented airbox lid| –$50
MAXIMUM COMBINED DEDUCTION| –$385
LOWEST POSSIBLE KIT PRICE – $1,605 AUD!
All applicable deductions may be combined.
Existing components must be compatible with our approved 350cc configuration. Third-party intake stacks and unapproved vented airbox lids are not supported.
OPTION 2 – INTRODUCTORY RIDE-IN, RIDE-OUT PACKAGE
$2,990 AUD
COMPLETE KIT – PROFESSIONALLY INSTALLED – SIX-MONTH LIMITED WARRANTY INCLUDED!
For customers who would prefer to have their 350cc conversion carried out by the team responsible for developing it, we are offering a special introductory installation package at our Tamworth, NSW workshop.
YOUR RIDE-IN, RIDE-OUT PACKAGE INCLUDES:
- Complete SSS 350cc Big Bore Performance Kit
- Professional installation by SSS MOTORCYCLES
- Six-month limited voluntary warranty on the eligible conversion
PACKAGE BREAKDOWN| PRICE
Complete 350cc Big Bore Kit| $1,990
Standard installation labour| $1,150
Normal supplied and installed price| $3,140
SPECIAL INTRODUCTORY FITTED PRICE| $2,990
YOUR SAVING| $150
RIDE IN. GET YOUR 350cc CONVERSION PROFESSIONALLY INSTALLED. RIDE OUT!
AND RECEIVE OUR SIX-MONTH LIMITED WARRANTY WHEN THE COMPLETE CONVERSION IS FITTED BY SSS MOTORCYCLES!
The warranty applies subject to our written warranty terms and conditions.
Supporting exhaust and air filter upgrades are additional unless otherwise specified.
OPTION 3 – BUY A BRAND-NEW HONDA CRF300L OR CRF300 RALLY WITH OUR SSS 350cc KIT ALREADY INSTALLED!
NEW MOTORCYCLE. BIG BORE PERFORMANCE. AUSTRALIA-WIDE DELIVERY.
IN THE MARKET FOR A BRAND-NEW HONDA CRF300L OR CRF300 RALLY?
SSS MOTORCYCLES can help you purchase a brand-new motorcycle and have it professionally fitted with our SSS 350cc Big Bore Performance Kit before delivery!
Through our arrangements with nearby authorised motorcycle dealerships, we can source a brand-new Honda CRF300L or CRF300 Rally at a highly competitive price.
We can then arrange for the motorcycle to be fitted with our complete 350cc performance conversion at our Tamworth workshop.
YOUR COMPLETE MOTORCYCLE PACKAGE CAN INCLUDE:
- Brand-new Honda CRF300L or CRF300 Rally sourced through our dealership arrangements
- Competitive new motorcycle purchase pricing
- Complete SSS 350cc Big Bore Performance Kit
- Professional installation by SSS MOTORCYCLES
- Dedicated SSS 350cc ECU calibration
- Optional approved intake and exhaust performance upgrades
- Six-month limited voluntary warranty on the SSS-installed conversion, subject to warranty conditions
- Australia-wide delivery of your completed motorcycle
ONE COMPLETE PACKAGE – READY FOR YOUR NEXT ADVENTURE!
Whether you're purchasing your first CRF300 or upgrading to a brand-new motorcycle, we can help coordinate the purchase, performance conversion and delivery.
AUSTRALIA-WIDE ENQUIRIES WELCOME!
New motorcycle pricing, availability, registration arrangements, modification compliance and delivery costs will be confirmed individually.
INTERESTED IN A COMPLETE NEW MOTORCYCLE WITH OUR SSS 350cc CONVERSION?
CONTACT SSS MOTORCYCLES FOR FURTHER INFORMATION AND A PERSONALISED PACKAGE QUOTATION.
PRE-ORDER INFORMATION
PRE-ORDER ONLY – LIMITED INTRODUCTORY OFFER
The SSS 350cc Big Bore Performance Kit is currently available on a pre-order basis.
PLEASE ALLOW APPROXIMATELY 2–3 WEEKS FROM PURCHASE TO RECEIVE YOUR KIT.
This is an estimated timeframe and may vary depending on production schedules, component availability and freight transit times.
Customers selecting our ride-in, ride-out installation package will need to arrange a workshop booking, subject to availability.
Complete new motorcycle packages are subject to dealership stock, workshop scheduling and delivery arrangements, with individual timeframes confirmed when quoting.
SIX-MONTH LIMITED WARRANTY – SSS MOTORCYCLES INSTALLATIONS
PROFESSIONALLY INSTALLED BY SSS MOTORCYCLES
When the complete 350cc conversion is fitted by SSS MOTORCYCLES at our Tamworth workshop, the eligible conversion is supplied with a six-month limited voluntary warranty, subject to the applicable written warranty terms.
The warranty applies to our approved engine configuration and is subject to appropriate maintenance, fuel quality and operating conditions.
Additional unsupported internal engine modifications fall outside our voluntary warranty coverage.
CUSTOMER OR THIRD-PARTY INSTALLATION
NO ADDITIONAL VOLUNTARY SSS MOTORCYCLES WARRANTY IS PROVIDED WHEN THE KIT IS INSTALLED BY THE CUSTOMER OR AN INDEPENDENT THIRD-PARTY WORKSHOP.
Correct mechanical assembly, component clearances, engine timing and installation procedures are critical to the reliability of this performance conversion.
We cannot verify the installation practices or mechanical condition of engines assembled outside our workshop.
AUSTRALIAN CONSUMER LAW
Nothing in these voluntary warranty conditions excludes, restricts or modifies any rights or remedies available under Australian Consumer Law, including applicable consumer guarantees.
IMPORTANT – ENGINE LONGEVITY DISCLAIMER
INCREASED PERFORMANCE COMES WITH INCREASED MECHANICAL LOADS
The SSS 350cc Big Bore Performance Kit delivers a substantial increase in horsepower and torque over the standard Honda CRF300 engine.
Customers must understand that increasing engine performance also increases mechanical stress on internal engine and drivetrain components.
This includes the piston, connecting rod, crankshaft, clutch, gearbox and associated components.
ANY SUBSTANTIAL INCREASE IN HORSEPOWER AND TORQUE CAN REDUCE ENGINE LONGEVITY COMPARED WITH AN UNMODIFIED STANDARD ENGINE.
We strongly recommend professional installation, correct maintenance, suitable fuel quality and responsible operation.
This performance conversion is intended for off-road and competition use. Customers are responsible for confirming compliance with applicable registration, insurance and road-use requirements, including for complete new motorcycle packages.
WHY CHOOSE SSS MOTORCYCLES?
REAL DEVELOPMENT. REAL MACHINING. REAL DYNO RESULTS.
At SSS MOTORCYCLES, performance development is much more than simply fitting aftermarket components.
With more than 26 years of motorcycle industry experience, our Tamworth-based operation specialises in motorcycle performance, engine development, ECU calibration and DYNO tuning.
Our 350cc program combines:
- Extensive in-house research and development
- Final precision machining in our Australian machine shop
- Critical dimensional and tolerance verification
- Dedicated ECU calibration development
- In-house Dynojet 250i DYNO testing
- Real-world performance evaluation
- Ongoing mechanical durability assessment
From our 301cc conversion producing approximately 30 rear-wheel horsepower, through to our 325cc package producing approximately 32 horsepower, and now our 350cc conversion exceeding 35 horsepower, we continue to develop the performance potential of the Honda CRF300 platform.
AUSTRALIAN DEVELOPED.
FINAL PRECISION MACHINING IN-HOUSE.
DYNO TESTED.
SSS MOTORCYCLES.
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ORDER YOUR SSS 350cc BIG BORE PERFORMANCE KIT TODAY!
HONDA CRF300L / CRF300 RALLY
35+ REAR-WHEEL HORSEPOWER
COMPLETE KIT ONLY – $1,990 AUD
INTRODUCTORY RIDE-IN, RIDE-OUT PACKAGE – $2,990 AUD
BRAND-NEW CRF300L OR CRF300 RALLY WITH SSS 350cc CONVERSION – CONTACT US FOR A QUOTE
SIX-MONTH LIMITED WARRANTY WITH SSS MOTORCYCLES INSTALLATION
PRE-ORDER NOW – APPROXIMATELY 2–3 WEEKS FOR KIT DELIVERY
SSS MOTORCYCLES
Tamworth, NSW, Australia
www.sssmotorcycles.com
Performance developed through engineering, precision machining and testing – not guesswork.