1. Concept & CAD DesignEvery product begins with a set of detailed engineering drawings. These designs ensure precise dimensions, mechanical compatibility, and performance expectations.2. First Prototype (Sample #1)The factory builds the initial sample based on the CAD drawings. This is often a rough draft that allows engineers to evaluate feasibility, structure, and potential points of failure.3. Testing & Problem IdentificationThe first prototype undergoes basic functional tests — such as ignition, running stability, fuel efficiency, and heat dissipation. Any issues are logged for review.4. Redesign Based on Test ResultsIf problems are detected (e.g. overheating, unstable idling, loose fittings), engineers revise key structural elements — such as piston geometry, crankshaft layout, carburetor airflow, or valve timing.5. Feedback from Users & CommunityWe actively collect feedback from early users and experienced builders to refine the design further. This step ensures real-world usability and not just theoretical performance.6. Second & Third Prototypes (Sample #2/#3)Multiple improved prototypes are created and tested again — often under various conditions and run cycles. Each iteration eliminates previous weaknesses and improves durability and consistency.7. Final Design ConfirmationOnly after all design and functionality concerns are addressed — and the internal and external teams approve — do we lock the final version (aka "design freeze").8. Mass Production SetupOnce the final version is confirmed, we begin mass production of key components like the crankshaft, cylinder block, and pistons. These are made in batches, and each batch must pass random sampling tests.⚠️ If a problem is found during production testing — for example, if a batch of crankshafts doesn't meet tolerance — the entire batch is scrapped and remade, which can cause significant delays.

We aim to ship as fast as possible, but delays may occur due to:🔩 Component failure during testing (e.g. crankshafts must be remade)🛠️ Design revisions after testing reveals an issue🧰 Missing accessories found during warehouse inspection🚚 Supply chain issues causing delayed delivery of parts📦 Packaging upgrades to prevent damage during transit🔍 Manual quality control that flags issues requiring rework

We’re really sorry if there’s been a delay in our response — we understand how frustrating that can be.Due to the time difference between your region and our support team, replies may not always be instant. However, please rest assured that:⏰ We aim to respond to every email within 24 hours (excluding weekends or holidays)🛎️ Checking and replying to emails is the very first thing we do when our team starts the day💬 After emails, we also go through all social media messages, private inboxes, and community commentsWe value every message and do our best to respond as quickly and thoroughly as possible.If it’s been over 24 hours and you haven’t heard from us, feel free to resend your message — we don’t want to miss it!Thank you so much for your understanding and patience. 🙏

Once the finished product arrives at our warehouse, it still goes through a strict internal QC process before we ship it to you.1.Visual Inspection – Check for scratches, misalignments, or cosmetic defects2.Assembly Check – Ensure all screws, parts, and wiring are correctly installed3.Function Testing – Spot test to confirm ignition, rotation, and cooling systems work4.Parts Verification – We manually check that every accessory listed is includedIf we detect missing parts or damaged items, we contact the factory to resend the components — which, again, adds a delay.

We understand it can be confusing — some products are ready to ship the next day, while others require a long wait. The difference mainly comes down to how and when each product is manufactured.Some models are produced in advance and kept in stock, so they can be shipped immediately after you place your order.However, for many complex engine models or newly released items, production only begins after a certain number of orders are placed. That’s because:These engines require specialized materials and parts, which are only ordered in bulkThe factory needs to reach a minimum production quantity before it can start making themOnce production begins, it still takes time to manufacture, test, and prepare for shipmentAfter the first batch is sold out, the next restock can take up to two months, depending on scheduling and material supplyIn short, your support helps us move production forward. Without enough confirmed orders, it’s difficult to launch a new batch — and your patience truly makes a difference.

I understand that you want your problem to be solved quickly. In order to allow our customer service to understand your needs and problems more quickly, please report your problems in the format of this blog. This will save both of us time in communication：https://www.stirlingkit.com/blogs/news/must-read-how-to-get-faster-after-sales-support-stirlingkit