NX-40005-4K Top End Kit 40.96/+1.00 11:1 Yam
NX-40005-4K Top End Kit 40.96/+1.00 11:1 Yam
Hurry up, only 1 item left in stock.
NX-40005-4K Top End Kit 40.96/+1.00 11:1 Yam
Unlock the true potential of your engine with the NX-40005-4K Top End Kit. Designed for performance enthusiasts, this kit is the ultimate upgrade for your Yamaha engine, providing exceptional power and reliability.
Key Features:
- Comprehensive Kit: Includes all essential components such as piston, rings, wrist pin, clips, top end bearing, and a gasket kit.
- MOS2 (Teflon/Molybdenum) Coated Skirts: A unique rolled-on application process that creates a bond 10 times stronger than traditional spray coatings. This feature enhances heat transfer, reduces friction, and minimizes the risk of cold seizures.
- Machined Smooth Heads: Engineered to reflect combustion heat and minimize carbon buildup, thereby protecting your piston. In performance tests, this innovation has shown to increase horsepower and fuel economy by up to 6%.
- Anodized Domes: Enhances heat resistance and durability. Pistons with anodized domes are 75% stronger than their non-anodized counterparts, ensuring longevity and reliability.
- Hypereutectic Casting Process: Delivers higher silicon content, resulting in reduced expansion rates and improved wear resistance while withstanding higher cylinder temperatures.
Benefits:
- Increased engine performance and responsiveness.
- Enhanced durability for long-lasting use.
- Improved fuel efficiency, allowing you to get more out of every drop of fuel.
- Maximized power delivery for an exhilarating riding experience.
Ideal Use Cases:
- Performance upgrades for racing enthusiasts seeking competitive edge.
- Rebuilding or refreshing older Yamaha engines for improved reliability and power.
- Customizing your bike for enhanced performance on the road or track.
Elevate your engine's performance with the NX-40005-4K Top End Kit and experience the difference on your next ride!
Couldn't load pickup availability
Get $20 off when you spend $1,000 or more! Learn more
Shipping & Returns
Shipping & Returns
📦 Shipping:
Orders are processed within 1–2 business days. Standard delivery takes 3–7 business days, depending on your location.
↩️ Returns:
You may return or exchange products within 60 days of receiving your order. Items must be in original condition with proof of purchase. If your item is defective or damaged due to manufacturing issues, we’ll replace it at no additional cost.
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
Let customers speak for us
The mat does fit well around the wheel wells. I did have to trim the mat for the rear bed tie down points. It was not hard and for the price I am very happy with the mat.
Excellent quality. The engraving is perfect.
What can you say about an adapter? Either it works or it doesn’t. Works fine. High quality. I used it to go from 1/4” male inverted flare to my Cherokee Wolf Pup 14cc propane regulator. Saved me from having to buy a different supply line.
Direct replacement, easy to install. Easy logistics from company
Works very well. Used to seal small cracks in my roof
Works very well. Used to seal small cracks in my roof
Works great helped fix the leak on the roof of our RV
Works great helped fix the leak on the roof of our RV
Discover more in our FAQ
Shoot our team an email, text or Chat & we’ll get back to you ASAP
How long does it take to process an order?
How long does it take to process an order?
Orders are typically processed within 1–2 business days. You will receive a confirmation email with tracking details once your order has been shipped. Please note that processing times may be slightly longer during high-demand periods or sales events.
Do you ship internationally?
Do you ship internationally?
Yes, we offer international shipping to most countries. Shipping rates and delivery times vary depending on the destination. Any applicable customs duties or taxes will be the responsibility of the recipient.
What is your return policy?
What is your return policy?
We accept returns within 60 days of order date. To be eligible, items must be unused, in their original packaging, and accompanied by proof of purchase. If the item is faulty or damaged, we will cover the return shipping and provide a replacement or full refund.
We have a 60-day return policy, which means you have 60 days after the order date to start a return
To be eligible for a return, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase.
Starting a return is quick and easy. Just follow these simple steps:
- Locate your order number, which can be found in the confirmation email or on the packing slip.
- To start a return click here: or you may follow this link: https://www.rvautoparts.com/apps/returns
- Provide us with the necessary information, including your order number and the reason for your return.
- Choose your preferred return method. We offer convenient options such as self-ship or label printing.
- Once you've completed the return request, you'll receive a confirmation email with further instructions.
If your return is accepted, we’ll send you a return shipping label, as well as instructions on how and where to send your package. Items sent back to us without first requesting a return will not be accepted.
You can always contact us for any return question at contact@rvautoparts.com.
Damages and issues
Please inspect your order upon reception and contact us immediately if the item is defective, damaged or if you receive the wrong item, so that we can evaluate the issue and make it right.
Exceptions / non-returnable items
Certain types of items cannot be returned, like electronics if they have been opened, perishable goods (such as food, flowers, or plants), custom products (such as special orders or personalized items), and personal care goods (such as beauty products). We also do not accept returns for hazardous materials, flammable liquids, or gases. Please get in touch if you have questions or concerns about your specific item.
Unfortunately, we cannot accept returns on sale items or gift cards.
Exchanges
The fastest way to ensure you get what you want is to return the item you have, and once the return is accepted, make a separate purchase for the new item.
European Union 14 day cooling off period
Notwithstanding the above, if the merchandise is being shipped into the European Union, you have the right to cancel or return your order within 14 days, for any reason and without a justification. As above, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase.
Refunds
We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method within 10 business days. Please remember it can take some time for your bank or credit card company to process and post the refund too.
If more than 15 business days have passed since we’ve approved your return, please contact us at contact@rvautoparts.com.
Exceptions / non-returnable items
Certain types of items cannot be returned, like perishable goods (such as food, flowers, or plants), custom products (such as special orders or personalized items), and personal care goods (such as beauty products). We also do not accept returns for hazardous materials, flammable liquids, or gases. Please get in touch if you have questions or concerns about your specific item.
Unfortunately, we cannot accept returns on sale items or gift cards.
Exchanges
The fastest way to ensure you get what you want is to return the item you have, and once the return is accepted, make a separate purchase for the new item.
European Union 14 day cooling off period
Notwithstanding the above, if the merchandise is being shipped into the European Union, you have the right to cancel or return your order within 14 days, for any reason and without a justification. As above, your item must be in the same condition that you received it, unworn or unused, with tags, and in its original packaging. You’ll also need the receipt or proof of purchase.
Refunds
We will notify you once we’ve received and inspected your return, and let you know if the refund was approved or not. If approved, you’ll be automatically refunded on your original payment method within 10 business days. Please remember it can take some time for your bank or credit card company to process and post the refund too.
If more than 15 business days have passed since we’ve approved your return, please contact us at contact@rvautoparts.com.
- Returns accepted for 60 days
- Customer provides return shipping unless damaged in transit ( damage must be notated within 3 days of arrival)
- Subject to 10% restocking fee
- No final sale items added
Our dedicated customer service team is always ready to assist you throughout the return process. If you encounter any issues or have any questions, don't hesitate to reach out to us. We take pride in providing excellent customer service and ensuring that you have a positive experience.
We understand that returns can be frustrating, but we believe that the return process shouldn't be. That's why we've designed it to be as hassle-free as possible. We value your satisfaction and want to make sure that you're completely happy with your purchase.
What are your sizing options?
What are your sizing options?
This product does not require sizing. However, if you’re shopping for wearables or accessories on our store, detailed size charts are available on each product page to help you find the perfect fit.
