Important Update: Revised cylinders for Rotax MAX engine family

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BRP-Rotax always strives to provide products at the highest quality standards while ensuring they secure availability according to customers’ demands.

The cylinder is a key element regarding engine performance and its parity must always remain a key focus. To maintain and build upon the current parity within the Rotax platform, the decision has been taken to transfer the cylinder manufacturing to Austria, which will only improve the parity and availability to the ever-growing Rotax market

Technical Details

With the renewal of the casting and manufacturing tools, the best available technologies have been applied to maximize further the engine parity, durability, and product appearance of the engine.

• (1) Casting process which provides a uniform smooth casting surface
• (2) Extended CNC control machining (ports, port heights, chamfer of ports)
• (3) NiCaSil plated stop for exhaust valve (Senior MAX and DD2 cylinder only)

The revision of the casting tool has also allowed for the following inclusions:

• (4) Apply a QR-code for traceability of product quality
• (5) Apply the logo “ROTAX RACING” to foster the brand’s appearance

Additional product features

• The cylinders with the revised casting tool are 100% exchangeable with the current cylinders.
• The support plate (Rotax 251336) for the exhaust valve (Senior MAX and MAX DD2) must not be used for the revised cylinders.
• The performance and performance characteristics are identical to the current cylinders.
• The tolerance groups A, AB, and B for the cylinder bore (marked beside the QR code) are identical to the current cylinders.
• The reading of the QR code on a cylinder will provide a unique 6-digit number (not ascending but a random number).

This allows distributors to register and publish which cylinders have been supplied to their markets and is legal for national RMC events.

Learnings from extensive testing on engine dyno used by service centers

Before conducting performance testing on dynamic dynos, it is advisable to give preference to considering the following three aspects:

• The cylinder will reach its best performance after a one-hour run time.
• Confirm proper piston clearance.
• Jetting is about 2 points + higher (richer) than with the actual cylinder

Excellent parity result of revised cylinder

A sufficient sample size of cylinders has been tested professionally on a certified dyno  with exclusive oversight by BRP-Rotax. The following graph illustrates the parity of the revised cylinder. Extensive testing in cooperation with service centers has confirmed the same top performance level as good available equipment on the market (on track as well on dyno). The newly applied technology reduces the performance variation between the cylinders due to less manufacturing tolerances. By this, the parity and fairness will be further improved.

Summary

• To secure the future cylinder supply the cylinder manufacturing has been transferred to an Austrian partner.
• Extensive testing in cooperation with service centers has confirmed the same top performance level as good available equipment on the market (on track as well on dyno).
• The newly applied technology reduces the performance variation between the cylinders due to less manufacturing tolerances. By this, the parity and fairness will be further improved.
• Any Micro Max competitor that enters a US series event will be required to use the new cylinder including at the Rotax Winter Trophy, US Trophy East and West series, and US Trophy Final. Competitors competing in Mini MAX, Junior MAX, Senior MAX, and DD2 MAX will be allowed to use the new cylinder code 413530 or 413531 or old cylinder code# 223993 or 223994 for 2024 RMC events.
• Any USA Rotax Evo engine owner can contact their Service Center and they will have the opportunity to connect directly with their Distributor for a “Special priced” replacement cylinder for a limited time ending March 30, 2024.
• Cylinders will be available for purchase December 1, 2023.

Please contact J3 Competition Inc. – John Giacomelli | john@j3competition.com | 1-814-864-1846