The Yamaha XS650 is a popular line of motorcycles produced in the 1970s and early 1980s. Even today, they are still popular with the enthusiast market. However, since even the most recently produced model is almost 30 years old, the bikes generally do have a few problems. One of the most common is the starter.
Before investigating any problems with the starter itself, check to ensure the "Run/Off" switch is set to run, because the starter will not engage otherwise. You might also check to make sure that your ignition switch is in the right position.
Starters are useless without electricity, so make sure that your battery is charged. Use a volt meter to check the charge; if it is only partially discharged, use jumper cables to start the motorcycle. Since the XS650 uses a 12-volt system, it's okay to jump it from a car. If it's totally discharged, you'll have to replace the battery.
You should also check to make sure the battery is properly grounded, as this will prevent a circuit from being completed. Also check that the battery cables are all in good working order.
Another common point of failure is the electrical cable that leads from the battery to the starter. This should be periodically checked for frays, cuts and corrosion.
The starter on an XS650 isn't much different than the starter on a car, in that it uses electrical energy from the battery to turn a motor, which through the use of some mechanical method, turns the engine over, allowing it to start. When a starter goes bad on a car, it's not that big of a deal; they're easy to remove and replace.
The starter on an XS650 is a little different. First, it's integrated into the engine block, making it difficult to replace. Second, while the starter on a car uses a belt to turn the engine over, which is easily replaced, the starter on an XS650 uses a gear which is connected directly to the gearing of the transmission and engine. The most common point of failure on an XS650 electric start is the gear on the starter. You can usually tell when this is happening--the starter will make a grinding noise instead of turning over the engine, which is a sure sign that the gears are starting to be stripped off. It may still occasionally catch, and turn over the engine, but this will get more intermittent as time goes on, and it should be repaired.
To replace the gear, you will first need to drain the oil from the engine. On the bottom of the engine case is a 24-millimeter bolt that serves as an oil plug. Remove it to drain the oil. Next, you'll have to remove the left side cover from the engine. This will expose the starter, which looks like a round circle with a bolt coming out of it, near the front of the engine. Undo the bolt to remove the starter.
You may want to simply replace the starter rather than repair it. Though the actual starter motor is robust on the XS650, it still is prone to failure after 30 years.
If you don't want to repair the electric starter on an XS650, you don't actually have to. Every model of XS650 also has a manual kickstart. Because of this, even if the electric starter is totally dead, the motorcycle can still be started. The kickstart gearing is one of the more robust parts in the XS650, and is not commonly prone to failure. Even if it does fail, replacing it is not particularly hard to do, at least compared to the electric start, though it is difficult to line up correctly in its socket, and it still requires removing the side cover.
