STIHL MS 400 C-M, RS, Guide Bar Length 45 cm

The STIHL MS 400 C-M fitted with a 45 cm (approximately 18″) guide bar is a professional-grade petrol chainsaw designed for demanding forestry, tree-care and heavy-duty cutting applications. This 2025-edition model brings together advanced engine components, superior ergonomics and smart technology features to deliver high performance, durability and efficiency.

At the heart of the MS 400 C-M is a 66.8 cm³ displacement two-stroke petrol engine producing around 4.0 kW of power. The “C-M” designation indicates STIHL’s M-Tronic™ electronic engine management system, which automatically adjusts fuel and ignition timing for optimal performance across changing conditions. The model also introduces a magnesium piston – a first in its class – helping deliver a high power-to-weight ratio and improved acceleration. The magnesium-piston design means the saw is lighter yet maintains strong torque, making it more agile for professionals who require both reach and mobility.

With a 45 cm guide bar, the MS 400 C-M offers generous bar length for medium to large timber work, giving ample reach while retaining improved handling compared to the longest bars. Combined with the professional-grade RS chain (Rapid Super) and the robust build typical of STIHL professional saws, it is ideal for felling, delimbing, bucking logs and other intensive forestry tasks.

Ergonomics and operator comfort are thoughtfully addressed: the saw features an anti-vibration system to reduce operator fatigue during prolonged use, side-access chain tensioning for quick maintenance, tool-free fuel and oil caps for ease of service, and a pre-separation air-filtration system and HD2 filter for extended service intervals. The lightweight design (powerhead around 5.8 kg) means the saw is more manageable for overhead work or when maneuvering around large trees.

Durability and reliability are built in: the magnesium piston improves longevity and weight efficiency, the pre-separation filter system extends the operating interval before cleaning is required, and the advanced lubrication system ensures efficient chain/bar oil distribution even with longer bars. This combination makes the MS 400 C-M a strong choice for professionals who need a saw capable of heavy duty work yet still manageable in size and weight.

In real-world application, this chainsaw excels when you need both reach and mobility. The 45 cm bar provides reach for larger logs and thicker trees, while the lightweight building and ergonomic design reduce fatigue and enhance control. Whether you’re working in forest clearing, estate tree maintenance or year-round arborist operations, the MS 400 C-M (45 cm) gives you professional capability with excellent balance.

Key Features

• 66.8 cm³ petrol engine delivering ~4.0 kW of power

• Magnesium piston technology for improved power-to-weight ratio

• M-Tronic™ electronic engine management for optimal performance

• 45 cm (≈18″) guide bar for substantial cutting reach

• Professional RS chain (3/8″ pitch, high-performance)

• Anti-vibration system to reduce operator fatigue

• Side-access chain tensioning for quick adjustments

• Tool-free fuel and oil caps for easy servicing

• Pre-separation air-filtration and HD2 filter for longer service intervals

• Lightweight powerhead (~5.8 kg) giving excellent balance for a mid-sized professional saw

• Suitable for felling, limbing, bucking and general forestry or tree-care work

Benefits

• High efficiency: The 45 cm bar enables longer cuts per pass, reducing cycle time in larger timber work.

• Reduced fatigue: Lightweight construction and anti-vibration system make longer periods of work less tiring.

• Ease of use: M-Tronic management removes the need for manual carburettor adjustments and keeps performance consistent.

• Durability: Magnesium piston, robust filtration and professional components mean fewer breakdowns, lower service time and longer life.

• Versatile reach: The 45 cm bar is a great balance between reach for larger trees and manageability in tighter or mixed terrain.

• Professional finish: Strong torque and reliable cutting power mean cleaner cuts and higher productivity for arborist or forestry tasks.

Uses / Applications

• Forestry logging and thinning operations where trees are medium to large size

• Arborist work: felling, delimbing, bucking in estate or commercial tree management

• Property maintenance of large trees, estate gardens, tree removals

• Professional users or serious hobbyists needing one saw to cover a broad range of heavy duty applications

• Situations requiring longer bar reach but without sacrificing balance and control

Technical Data

• Engine displacement: 66.8 cm³

• Rated power output: ~4.0 kW

• Weight (powerhead only): ~5.8 kg (12.8 lbs)

• Recommended guide bar lengths: 40-63 cm range, 45 cm is within that range

• Power-to-weight ratio: ~1.45 kg/kW

• Oil pump: Variable-displacement oil pump for bar/chain lubrication

• Filtration: Pre-separation air filter with HD2 filter for longer service life

• Chain pitch: 3/8″ (for models with RS chain)