Description
Guarder SP120 Full Tune-Up Kit for TM M4-A1 Series (FTK-40)
This is Guarder’s SP120 full tune-up kit for Tokyo Marui M4-A1 series AEGs, part code FTK-40. Guarder is a respected Taiwanese maker of upgrade parts, and its full tune-up kits are designed to bring together a set of matched upgrade internals in one package, built around Guarder’s SP120 spring.
Buying a matched kit takes much of the guesswork out of upgrading a rifle, because the parts are chosen to work together rather than picked one by one. It is aimed at players who want a stronger, more consistent M4 and who are comfortable working on a gearbox or having a technician do it.
What the kit is for
A full tune-up kit is intended to upgrade the main internal parts of an AEG at once, improving durability and consistency over the stock set-up. The SP120 in the name refers to the Guarder spring the kit is built around. The full list of parts included is not stated in our listing, so please check the product photos to see exactly what you will receive.
Fitting and set-up
Installing a tune-up kit requires stripping the gearbox, so you will need gearbox tools, grease and experience. Gears need shimming, the air seal must be checked, and the angle of engagement should be correct to protect the piston. A stronger spring raises velocity, so chronograph the rifle after fitting and make sure it meets your site’s limits. A technician can install the kit if you prefer.
Key features
- Full tune-up kit from Guarder
- Built around the SP120 spring
- For Tokyo Marui M4-A1 series AEGs
- Matched parts that are designed to work together
- Aimed at improving durability and consistency
- Part code FTK-40
Compatibility
Listed for Tokyo Marui M4-A1 series AEGs, which use a Version 2 gearbox. Many clone M4s follow the Marui design, but some differ, so check your replica’s gearbox before ordering, or contact us.
Care and maintenance
After installation, use a suitable battery and keep the motor height correctly set. Store the rifle with the battery disconnected and fire a single shot in semi before long-term storage to relieve spring tension. Service the gearbox periodically.
Who is it for?
This kit is for owners of Tokyo Marui M4-A1 series AEGs, and technicians, who want a complete matched internal upgrade around the SP120 spring.
Please note: Always chronograph your replica after upgrading and wear eye protection when test-firing.
