$25 Off $250 / $50 Off $500, on Summit Racing Brand Products - Use Promo Code: VALUE

Make/Model Search
Make/Engine Search

Brands
Savings Central
Contact Us
Help Center
1-800-230-3030

Call Us
My Garage
Wish List
Order Status & Returns

Welcome
My Account

Order Status

Wish List
Savings Central
Shop by Brand
Shop Your Passion
- Shop Your Passion
- Truck / SUV
  
  Jeep®
  
  Restoration
  
  Stock Replacement
  
  Late Model Muscle
  
  Tools
  
  Gifts, Clothing, & More
  
  Circle Track
  
  Street Rod
  
  Powersports
  
  Paint & Body
  
  Marine
  
  Jr Dragster
Gift Cards
My Garage
See Our Catalogs
News & Events
Career Opportunities
Contact Us
Help Center
1-800-230-3030 1-800-230-3030
New Products
Shop by Make/Model
Sign In

Search Make/Model

Search Make/Engine

Sign In

Welcome
Account Dashboard
Profile
Order Status & Returns
Buy It Again
Wish List
Rewards Program
Gift Cards & Summit Bucks
Address Book
My Garage Settings
Email Preferences
Text Notifications
My Reviews
My Questions
Catalogs
Tax Exemption
Sign In

$25 Off $250 / $50 Off $500, on Summit Racing Brand Products - Use Promo Code: VALUE

Summit Racing SpeedCard - learn how to get 10% back - Get Details!

Filters

In Stock
- In Stock Items. Ships Today. (1) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- In Stock Items, Including at a Supplier. Ships In a Few Days. (8) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- All Items, Including Not In Stock (20) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Part Type
- Powersports Top End Engine Kits (7) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- Powersports Piston and Ring Kits (1) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Brand
- Quadboss (6) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- Namura (2) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Make/Model
Filter Options
- PowerSports (8)
Savings Central
- Clearance (1)

Selected Filters

Filter Results by Vehicle

Loading...

Home
Engines & Components
Engine Kits & Rotating Assemblies
Product Results

Availability

- In Stock Items. Ships Today. (1) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- In Stock Items, Including at a Supplier. Ships In a Few Days. (8) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- All Items, Including Not In Stock (20) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Filters
Part Type
- Powersports Top End Engine Kits (7) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- Powersports Piston and Ring Kits (1) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Brand
- Quadboss (6) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
- Namura (2) The options in this area are not available since you have already selected choices in the area. Use the "Get Results" button for your current choices.
Make/Model
Filter Options
- PowerSports (8)
Savings Central
- Clearance (1)

Engine Kits & Rotating Assemblies

Showing In Stock Items. Show All 20 Items.

Individual Parts

Part Groups

Results 1 - 8 of 8

Namura Powersports Top End Engine Kits NX-40025-6KA

Namura Powersports Top End Engine Kits NX-40025-6KA

Namura Powersports Top End Engine Kits NX-40025-6KA

TOP END REPAIR KIT

Part Number: NTI-NX-40025-6KA

Not Yet Reviewed

Estimated Ship Date: Today

...Loading

Estimated Ship Date: Today

Quadboss - Powersports Top End Engine Kits for 1988-2006 YFS200 BLASTER - 563912

Quadboss - Powersports Top End Engine Kits for 1988-2006 YFS200 BLASTER - 563912

Quadboss - Powersports Top End Engine Kits for 1988-2006 YFS200 BLASTER - 563912

QB FULL TOP END SET

Part Number: QDB-56-3912

Not Yet Reviewed

Estimated Ship Date: May 18, 2026 if ordered today

...Loading

Estimated Ship Date: May 18, 2026 if ordered today

Namura Technologies Top-End Repair Kits for 2003-2006 KFX80, 1987-2006 LT80 QUADSPORT - NA-30080-2K

Namura Technologies Top-End Repair Kits for 2003-2006 KFX80, 1987-2006 LT80 QUADSPORT - NA-30080-2K

Namura Technologies Top-End Repair Kits for 2003-2006 KFX80, 1987-2006 LT80 QUADSPORT - NA-30080-2K

TOP END REPAIR KIT

Part Number: NTI-NA-30080-2K

5.0 out of 5 stars ( 1 )

Estimated Ship Date: May 26, 2026 if ordered today

...Loading

Estimated Ship Date: May 26, 2026 if ordered today

Quadboss Powersports Top End Engine Kits 563907

Quadboss Powersports Top End Engine Kits 563907

Quadboss Powersports Top End Engine Kits 563907

QB FULL TOP END SET

Part Number: QDB-56-3907

Not Yet Reviewed

Estimated Ship Date: May 19, 2026 if ordered today

...Loading

Estimated Ship Date: May 19, 2026 if ordered today

Quadboss - Powersports Top End Engine Kits for 1988-1990 LT500R QUADRACER - 563924

Quadboss - Powersports Top End Engine Kits for 1988-1990 LT500R QUADRACER - 563924

Quadboss - Powersports Top End Engine Kits for 1988-1990 LT500R QUADRACER - 563924

QB FULL TOP END SET

Part Number: QDB-56-3924

Not Yet Reviewed

Estimated Ship Date: May 18, 2026 if ordered today

...Loading

Estimated Ship Date: May 18, 2026 if ordered today

Quadboss - Powersports Top End Engine Kits for 2001-2008 TRX250EX SPORTRAX, 2009-2020 TRX250X - 563971

Quadboss - Powersports Top End Engine Kits for 2001-2008 TRX250EX SPORTRAX, 2009-2020 TRX250X - 563971

Quadboss - Powersports Top End Engine Kits for 2001-2008 TRX250EX SPORTRAX, 2009-2020 TRX250X - 563971

QB FULL TOP END SET

Part Number: QDB-56-3971

Not Yet Reviewed

Estimated Ship Date: May 19, 2026 if ordered today

...Loading

Estimated Ship Date: May 19, 2026 if ordered today

Quadboss Powersports Top End Engine Kits 563914

Quadboss Powersports Top End Engine Kits 563914

Quadboss Powersports Top End Engine Kits 563914

QB FULL TOP END SET

Part Number: QDB-56-3914

Not Yet Reviewed

Estimated Ship Date: May 19, 2026 if ordered today

...Loading

Estimated Ship Date: May 19, 2026 if ordered today

Quadboss - Powersports Top End Engine Kits for 1987-1992 TRX250X, 2009 TRX300X - 563902

Quadboss - Powersports Top End Engine Kits for 1987-1992 TRX250X, 2009 TRX300X - 563902

Quadboss - Powersports Top End Engine Kits for 1987-1992 TRX250X, 2009 TRX300X - 563902

QB FULL TOP END SET

Part Number: QDB-56-3902

Not Yet Reviewed

Estimated Ship Date: May 18, 2026 if ordered today

...Loading

Estimated Ship Date: May 18, 2026 if ordered today

1

Page 1 of 1

Modal Header

Contact us with questions.

Call To Order

This is a custom order part. You can order this part by Contacting Us.

Summit Racing Speedcard. Synchrony Car Care.

Summit Racing Equipment SpeedCard

Jumpstart Your Next Project!

View Details|See if you Prequalify

Stay Updated with Emails from Summit Racing

Never miss a sale on new parts, tools, and more!

= Required

First Name

Last Name

Email Address Email required

See Our Catalogs

News & Events

News & Events Home
OnAllCylinders (blog)
Calendar of Events
New Product Releases
Summit Racing News
News You Can Use
Featured Vehicles
Media Center
Sanctioning Bodies

Help

Help Center
Return Policy
Beat-A-Price Guarantee
Payment Options
Contact Us

Social

Facebook
X/Twitter
Instagram
Pinterest
YouTube
Podcast

About Summit

Corporate History
Retail Locations

My Account

Profile
Email Preferences
Order Status & Returns
Wish List
Address Book
My Reviews
My Questions
My Garage
Sign In

Career Opportunities

More

Summit Racing Credit Card
Gift Cards
Calculators & Tools
Promo Exclusions
Become an Affiliate
Summit Racing Rewards Program
Summit Racing Equipment Protection Plan

Terms of Use | Privacy and Security | Site Accessibility
Copyright 2026 by AUTOSALES, INCORPORATED
dba Summit Racing Equipment | Trademarks

Let's Build it Together^™

Modal Header