Suzuki AN 650

Potential problems to be aware of

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The DR650SE engine has an outstanding reputation for long, trouble-free service life. Of course, it should go without saying that proper maintenance is the key to that longevity, and Suzuki’s engineers have made your life easy in that regard. The DR650 is a remarkably friendly bike to work on, generally.

It’s also a well designed, low-stressed engine, with an excellent lubrication system.

Nothing’s perfect, though.

Neutral Sending Unit (NSU)- This is a sensor within the engine that lights the Neutral indicator on the dash. It is held in place by two screws. There are very rare instances where these screws have backed out and fallen into the engine. I’m sure everyone can imagine the carnage if one of those screws managed to bounce between a connecting rod and a crankshaft lobe at 5000 rpm.

Now throw in the image of hot oil spilling out of your engine all over the rear tire at 70 mph as the engine locks up. Not pleasant. Clearly, this is a worst-case scenario, but you get the idea.

The extremely rare cases where these screws fall out seem to happen to higher mileage bikes, but that’s certainly no guarantee. There is one possible warning sign. If your neutral light stops working, even intermittently, SHUT DOWN THE BIKE UNTIL YOU FIND OUT WHY. The fix requires removing the engine cover, appling threadlock and re-tightening the screws. Some prefer to remove the sensor entirely.

Suzuki AN 650

Crisis averted. A magnetic oil drain bolt may go a long way to catching a stray screw before it has a chance to cause more significant damage. Some chose to replace with NSU screws with 5mm x 20mm hex head bolts (to engage a few more threads) and 5mm serrated lock washers. The NSU (Neutral Sending Unit)


NSU Links: Avoiding NSU Problems by macdesign (ADV Rider). OHH $hit Oil Change. by chaos_magic_man (Thumpertalk) NSU Checkup How To by greenlizard (DRRiders.com)

And while you are checking your NSU screws. Primary Reduction Gear Crank Nut: There have been a number of documented cases of the primary gear retaining nut coming loose and backing off. While you have the clutch cover off it would be a good idea to check this nut for proper torque (72.5 ft lbs). The nut is a left handed thread.

If you find the nut is loose on your machine you will want to check the condition of the key. If there is any side wear or grooving replace the key. Using some removable threadlocker on nut would not be a bad idea either.

==== Countershaft Seal: This is rare but, if it happens, could be a disaster. The seal around the countershaft (front sprocket shaft) can be pushed out, which essentially dumps all oil from the engine/transmission. This could cause loss of control due to oil getting on the rear wheel, damage to the engine, and of course the ‘bike will be unridable until the seal reinstalled and oil added. There is much debate on the cause, but there is also a simple, cheap fix available – several seal retainers are available commercially, or you can build your own.====

CS Seal Links:

Suzuki AN 650
Suzuki AN 650
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