The rear suspension is adequate for the majority of riders but there are those who are using the machine in offroad situations who will require some upgrades varying from simple shock replacement to longer travel and larger rear wheel and wider rim. In addition some riders feel the need to reduce the height of the machine.
F650GS & G650GS rear shocks are the same Part No 33 53 7 728 374, the 2010+ shock is Sachs not Showa
Dakar & Sertao rear shocks are the same Part No 33 53 7 728 377, the 2010+ shock is Sachs not Showa
The items to watch and information on changes are below.
The difference in height of the rear suspension between the GS and Dakar
is set by different shock absorber lengths rather than by different length linkages. The shock absorber lengths (in mm) are:
GS 315 - Stroke 47.5, Dakar 326 - Stroke 59.5, Linkage Ratio 3:50
An 18" rear wheel coupled with a 3.25" width rim can widen the tyre choice and raise the rear by 1/2". Clearance on the fuel tank is minimal and needs to be checked. The chain needs 114 links and the adjusters need additional thread length. Adjuster pdf The 650X has an 18" rear wheel.
The swingarm axle bearings are unsealed and require maintenance or they wear prematurely and can seize. The axle can be difficult to remove if it is left for too long. The pdf here outlines how to add seals to prevent the problems without swingarm modification. Swingarm Bearing Mod
The suspension linkages require maintenance and the bolts are known to bend and in some cases break. At least
some bolts are fully threaded and weaker than they should be. The bolts should be checked and replaced.
The bolts are M10x51, M10x65, M12x110 and worthy spares to carry.
Fitting replacement forks without shortening such as the YZ forks it is necessary to raise the rear by 25mm.
The STD linkages are 85mm centre to centre, 25mm rise are 76mm C-C
Contact Aquatic at Advrider for raising links
Kouba make 1" and 2" lowering links for the GS as well as replacement
STD links. The front forks can be raised 7/8" easily to maintain geometry. Lowering the GS more than 1" would not be recommended unless the suspension travel was reduced. Kouba Online
Compression adjustment can be added to the Showa rear shock.
The adjuster is Showa Type B0292 and is rebuildable.
This is a brief write up by Dansin over at Advrider. Download pdf
The shock can also be rebuilt, a write up will be added
Most of the manufacturers have shocks available with choices on adjustability and remote reservoirs