Suspension and Drive Train Repairs

Things to check
Lower Shock Bolts - The bolts are fully threaded & known to wear & break, they are worth checking periodically
Chain Adjuster Bolts - Tighten the bolts after tightening the axle, the bolts are known to vibrate loose.
Dakar Chain Roller - The bolt is known to vibrate loose, it is worth checking periodically.

Front Suspension

Fork repair procedures are well covered in the BMW repair manuals. The majority of components are common between all the year models and the Dakar and Sertao. See the modifications Section for upgrades. The fitting of emulators to separate compression and rebound circuits and enable reduction of spring preload is strongly recommended. The piston rod retaining bolts in the lower fork leg are 10mm on the G Series. (8mm F Series)

The length of the Showa forks on 00-09 model 650GS and Dakar is set by a different damper tube length not a different stanchion length as many of us believed. The Dakar and Sertao rear shock is the same part number

Part No List

2000 to 2011 Part No List compiled from on line parts fiche. GS Fork Parts.pdf

Fork Brace and Axle Lugs

The fork brace is known to crack, during maintenance it is worth checking.
A cracked fork brace will give a less precise feel on the front suspension and increase twisting loads on the axle lugs.

Dual Spark axle lugs are stronger but a little excessive force can crack them. After a fall or during maintenance it is worth inspecting the axle lugs.


Rear Suspension

The GS and Dakar have different length shock absorbers rather than different linkages.

The lengths (in mm) are: GS 315 - Stroke 47.5, Dakar 326 - Stroke 59.5, Linkage Ratio 3:50

Swingarm Bearings

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

Swingarm Linkages

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.

Rear Shock

The Showa shock absorber on the Dakar is DIY rebuildable, the GS with no remote reservoir requires a suspension specialist to dismantle. A write up on rebuilding the the Dakar shock has been done by PeteHK There is a link in the pdf to the thread at f650 for discussion. Dakar Shock Rebuild pdf

The shock bushes can perish and the steel inner wear. The top bush is a press fit and could be replaced but no replacement has been found.
Top bush dimensions are 10x20x30mm, Outer steel ring width is 27mm.
Lower bush dimensions, not measured as yet.


Chain Adjusters
The chain adjuster bolts do not allow the full range of adjustment, the threads can be extended by to allow further adjustment. It is normally only needed with 114 link chains and different sprocket sizes. Adjuster pdf
Chain Guard
The BMW F650GS chain guard and possum scraper breaks and does not suit all people. TT make an alloy one but it fractures. A low cost alternative is the G650GS guard. BMW Part No 01 46 62 7 727 156
GS Chain Rollers
There are upper (Dakar only) and lower chain rollers, the lower roller may have either an 8 mm or 10mm centre bolt. Information on the rollers and alternatve replacements is in the pdf. Chain Roller Info pdf

Wheel Bearings
Remove the wheel bearings and sprocket carrier bearings using blind hole pullers not the bash method. A little heat on the hub or sprocket carrier is also advisable. These steps minimise damage to the hubs.
Blind hole bearing puller sets like the kits in the pictures above are low cost & fit most motorcycle wheel bearings. When fitting wheel bearings use bearing pullers and a little heat to fit the bearings. Thirty percent of bearing failures are due to improper installation. Pullers are easy to make up to suit without major expenditure.