INNTECK KYB Shock Spring for YAMAHA YZ 80, YZ 85 1997-2027

On YAMAHA YZ 80, YZ 85 from 1997 to 2027, the INNTECK KYB shock spring fits in place of the original part. The spring rate decides the height at which the rear end works. A spring suited to your weight makes the rear more stable in the bumps, better balanced with the fork and easier to set up.

Specifications

• Brand: INNTECK
• Manufacturer part numbers: QS3735, QS3740, QS3742, QS3745, QS3750, QS3755
• Diameter: 55 mm, length: 220 mm
• Available versions: 35 N/mm: ref. QS3735; 40 N/mm: ref. QS3740; 42.5 N/mm: ref. QS3742; 45 N/mm: ref. QS3745; 50 N/mm: ref. QS3750; 55 N/mm: ref. QS3755

Choosing the right spring rate

First set the rider sag to the manual's value using the preload collar, then measure the static sag (bike without rider): if it is too small, the spring is too soft for you; if it is too big, it is too stiff. Then change the spring rate by one or two steps.

When to replace it?

• Impossible to get the right rider sag without tightening or loosening the preload a long way.
• The rear end bottoms out often or squats under acceleration: spring too soft.
• The rear end bounces and lacks traction: spring too stiff.
• You weigh clearly more or less than the standard rider the manufacturer designed for.

Spring rate is given in N/mm (1 kg/mm is about 9.81 N/mm). Check the shock type (KYB, SHOWA, WP with linkage or WP PDS, which has no linkage) and the dimensions: the diameter and length must match your shock.

Fitting tips

1. Remove the shock as described in the manual, with the bike supported so the rear wheel is off the ground.
2. Back the preload off completely, remove the spring seat and change the spring.
3. Refit the shock to the specified torque, then set the rider sag with the preload.
4. Rebalance the fork afterwards if needed: a higher or lower rear end changes how the front end behaves.

Spare parts and items to plan

• Shock rebuild kit : PROX · PIVOT WORKS
• Linkage bearings : PROX · PIVOT WORKS

Frequently asked questions

Who is a progressive spring for?
Its rate increases as it is compressed: soft at the start of the travel for comfort, firmer toward the end of the travel to resist bottoming out. It is mainly used on WP PDS shocks, which are fitted without linkage.

Compatibility

Check the exact model and year of your bike in the list below before ordering.

Fits:
YAMAHA YZ 80 2001
YAMAHA YZ 80 2000
YAMAHA YZ 80 1999
YAMAHA YZ 80 1998
YAMAHA YZ 80 1997
YAMAHA YZ 85 2027
YAMAHA YZ 85 2026
YAMAHA YZ 85 2025
YAMAHA YZ 85 2024
YAMAHA YZ 85 2023
YAMAHA YZ 85 2022
YAMAHA YZ 85 2021
YAMAHA YZ 85 2020
YAMAHA YZ 85 2019
YAMAHA YZ 85 2018
YAMAHA YZ 85 2017
YAMAHA YZ 85 2016
YAMAHA YZ 85 2015
YAMAHA YZ 85 2014
YAMAHA YZ 85 2013
YAMAHA YZ 85 2012
YAMAHA YZ 85 2011
YAMAHA YZ 85 2010
YAMAHA YZ 85 2009
YAMAHA YZ 85 2008
YAMAHA YZ 85 2007
YAMAHA YZ 85 2006
YAMAHA YZ 85 2005
YAMAHA YZ 85 2004
YAMAHA YZ 85 2003
YAMAHA YZ 85 2002