There are a few simple tools, tips and tricks which can make working on the GS a little easier.
There are also a few items which are worth keeping a close eye on as they can cause large failures.
Throttle Body - The Throttle Body can crack at the base and cause poor running problems worth checking.
Neutral Switch - Clean and seal with silicon, it can suffer electrical leakage to earth in wet weather.
Indicator Switch - Repack with waterproof grease periodically it has electrical leakage to earth in wet weather.
Lower Shock Bolts - The bolts are fully threaded & known to wear & break, they are worth checking periodically
Swingarm Bearings - The bearings are not sealed, they wear and can sieze, see the rear suspension page.
Chain Adjuster Bolts - Tighten the bolts after tightening the axle, the bolts are known to vibrate loose.
F650GS mirrors are unthreaded and use an adaptor to mount into the lever perches. Any mirror with a 10mm stalk (F650GS) or 12mm (G650GS 2010+) and suits your requirements can be used. Cut the thread off and fit it. Where a perch 8mm thread is damaged it can either be helicoiled or tapped to 10mm and the other BMs (eg F800GS) adaptor used.
F/G 650GS - 10mm stalk / 8mm thread - BMW adaptor 51167672399
2010+ 650GS - 12mm stalk / 10mm thread - BMW adaptor 51167723432
Other BMs - 10mm stalk / 10mm thread - BMW adaptor 51167673982
On ABS equipped models it is advisable to disconnect the ABS control unit when isolating the battery for charging or jumpering. It has been found that there is a second path to earth through the ABS unit. Analysis of a damaged wiring harness from one machine where jumper leads were momentarily reverse conected showed only the earth wire to the ABS and the ABS socket were badly damaged. Disconnection of the ABS would have avoided the damage.
Take care with the chain adjusting bolts, they can work loose, the bolts and end plates fall off. After tightening the axle check the adjusters and tighten. Fitting nyloc nuts inside the swing arm on the bolts is a good idea.
The thermostat can be difficult to fit on re assembly. The spring clip does not slide into place. Ensure the thermostat holder is in all the way with nothing sticking out. Try putting the clip in without the thermostat and it should go in easily. Then fit the thermostat and push it in as hard as you can and the clip will slide in easily.
The 00-04 oil drain plug is easily damaged so take care when removing the plug.
Get a 6 sided socket and grind the front edge as shown to prevent damage.
The BMW revised plug or a drain plug with magnet is recommended.
This drain plug is used on the CS/X/G650/F Twin BMW models.
The BMW Part No - 11 13 7 708 604 Screw Plug, Magnetic - M24x2
EU owners often ask what is the mystery connector on the top of the fuel tank. It is for the US fuel tank vent valve. The valve is operated by the BMS-C engine management system while riding. It is monitored by the BMS-C and excess current though the circuit could damage the BMS-C.
Be sure to use the correct plug for your model. The single spark models use a non resistive spark plug
NGK D8EA. The dual spark and CS models use a resistive plug NGK DR8EA as
they have Coil on Plug units. The "R" in an NGK No indicates resistive.
See Modifications/Ignition Upgrades, Pulstar have capacitive plugs available which improve combustion.