Starter Gear Assembly (81-83 Models) and 84 + Pic # 2
Starter Gear Componets Pic #3
Plantetary Gears - Left is the lower, right is upper
(shim is .4 mm diameter, 10mm width, 2mm thick)
This is the stock Yamaha idler gear shim - engine side
Yamaha Part # 90201-357E4
I have focused on 2 areas, the starter itself and the starter gears on the left side of the engine. There are phases of repair-I like that big word " phases".
Your Battery - the Heart of the System
Voltage Drop in Starting Circuit
Connections in a high amperage circuit such as a starter can do strange things. They can appear to be clean and tight, yet at the same time they can be the cause of a starting system failure. A dirty or loose connection will pass 12 volts (nominal) through it at low amperage with little or no current loss, yet at higher loads it will not be able to handle the amperage and the starter will either turn too slowly to start the engine, or won't turn at all.
Fortunately, a loose or dirty connection has a few distinct characteristics that makes it easy to spot--if you know what to look for.
Any time there is a bad connection, there will be a voltage drop across it. Electricity is never "lost", it is simply converted to another form of energy, be it light, heat, motion, etc, or a combination of two or more. Loose connections in a starting circuit will get hot almost invariably when subjected to high current loads, such as attempting to start (heat). A very bad connection will arc (light). Touching a very hot connection will make one draw one's hand back quickly (motion). :-)
Voltage drop is measured by placing one lead of the volt meter on one part of the connection (i.e. the battery post) and the other lead on the other part of the connection (i.e. the battery cable connector). When the engine is cranked over, the voltmeter will read voltage if there is resistance in the connection. Any connection is considered "bad" if there is more than .2 volts showing across the connection while cranking. There should not be more than .5 volts total loss from the positive post of the battery to the starter motor connection. This includes the starter solenoid as well as all cable connections.
To do a voltage drop test, first remove the necessary body panels to expose both terminals of the battery. Set the voltmeter on a low scale (3-5 volts DC is good). Put the negative lead of the meter on the negative battery post and put the positive lead on the negative battery cable end. Crank the engine with the kill switch engaged to keep the engine from starting. The reading on the voltmeter should be .2 volts or less. If it is more than .2 volts, remove the connection, clean it, and tighten it securely. Repeat the test until results are satisfactory, then connect the negative voltmeter lead to the negative battery cable end, and the positive voltmeter lead to the other end of the negative cable. Crank again. If the reading is not within specs, remove and clean the connection and test again. When the test results are satisfactory, put the negative voltmeter lead on the frame end of the negative battery lead, and put the positive voltmeter lead on a good frame ground. Crank again. If the reading is not within specs, remove and clean the connection and test again.
Testing the positive side of the circuit is similar. Start with the positive battery post and the cable connector, this time put the positive lead of the voltmeter on the positive battery post and put the negative lead of the voltmeter on the connector of the positive battery cable. Crank and repair as necessary as above. Repeat the sequence for every single connection down the line all the way to the starter motor. Remember to check the connection between crimped terminals and the actual cable. Corrosion can set up inside a crimped connector and make it useless even though it looks clean and tight on the outside. Use the sharp point on the voltmeter probe to puncture the insulation of the cable when doing a voltage drop test on terminal ends.
When testing from one terminal of the solenoid to the other, the voltmeter will read full battery voltage until the starter switch is pressed. For this reason one should do one of the following:
Set the voltmeter to a scale of 12 volts or more until the starter is engaged, then switch to a lower scale to read voltage drop across the solenoid, or:
Have an assistant to crank the engine, and make the voltmeter connection after the starter has engaged.
In either case, set the voltmeter to a scale of 12 volts or more, or remove the voltmeter connection prior to stopping cranking to avoid damage to the voltmeter.
A voltage drop of more than .2 volts across the starter solenoid calls for the repair or replacement of the solenoid.
Total starting circuit voltage drop is measured from the positive battery post to the terminal on the starter motor. This connection will read full battery voltage when connected, but should show less than .5 volts while cranking. Any reading over .5 volts indicates a voltage drop somewhere in the starting circuit which must be repaired.
1. Starter Shim Repair
2. Starter Weld Repair
3. Starter Gear Repair
I'll try to cover these as best I can. I am not reponsible for any damage to your bike. Follow these repairs at your own risk!!!
In many of these grinding starter cases , the starter is not at fault. The culprit is the starter gears and the gear assembly that the starter is coupled to. The Virago system is very archaic compared to most starting systems found on motorcycles.
As the starter motor and gear begin to spin, they in turn spin a reduction gear that is coupled to a spiral idler wheel . On the spiral idler wheel is a throw gear , which, when the spiral idler wheel begins to spin, travels down the Idler Shaft towards the crankshaft gear on the end of the rotor . This throw gear has a unique horseshoe shaped clip that is fitted around it. This clip holds the gear tightly to prevent it from spinning as it travels down the shaft. Once the throw gear is completely mated with the teeth of the crank, the spinning motion of the shaft overcomes the friction of the spring and the gear spins with the shaft and subsequently turns the crank. When the engine fires and the starter button is released, the compression spring, pushes the throw gear back away from the crank.
The problem is as this horseshoe clip wears, (and they do), it allows the throw gear to start spinning before it even reaches the teeth on the crankshaft. Imagine for a moment, a spinning gear being that is being forced against another much bigger gear that is stationary and has quite a load behind it. The smaller, quickly spinning gear bounces off the bigger one as it tries in vain to mate up. Thus the noise.
Ring Gear -Worn throw gear to the left (side of teeth worn away)
When the wear first begins to happen you will get the occasional grind until the gear finally manages to mesh up and the engine starts. But as the clip wears and the gear continues to bump and grind, the teeth of the throw gear begin to be wear away. As the wear becomes greater, it becomes almost impossible for the throw gear to properly engage with the crankshaft.
It appears that Yamaha had anticipated this problem when they originally conceived the Virago. They engineered it so the throw gear would be the gear to wear (softer metal, easier to replace) and not the rotor gear of the crankshaft (harder metal, very difficult and expensive to replace). They also placed a magnet directly beneath the starter gear assembly to catch all those metal fillings that are ground off the gears by this meshing action.
1. Starter Symptons
Of my 6 Viragos only one has a good starter. My 83 XV500 starts everytime and no whining, groaning,slipping or missing. My other Viragos all have developed the usual problems. As a winter project I decided to fix the problem on each bike. You can have a slipping starter or engagement problems. Make sure your carbs are tuned, a fully charged battery (VERY IMPORTANT), and the wiring is in good condition from the battery-switch-solenoid-starter. I noted on 3 starters that I worked on that the long bolts holding the starter end peices were slightly twisted. I think over time the torque of the starting turning against the frame results in twisting of the starter. I replace the long bolts with stock bolt/nuts from the hardware store. I found that I can tighten these easier with wrenchs than a phillips screwdriver. If the bolts are twisted it's a sign tht the locking pin (part #3 pic #5) is not place.
(a)- drain the oil
(b)- remove the battery (not necessary but I always remove it to be safe)
(c)- remove the left side engine cover - bolt lenghts are not all the same- use a piece of cardboard and put each bolt in a respective hole on the cardboard, so you can put it back on correctly. There are 3 hidden bolts on the engine side cover near the clutch cover.
(d)- be careful when removing the cover, don't rip the gasket, or tear the wiring. You can sit the cover on a box to prevent strain on the stator wiring. Be careful the starter gears don't fall out. Look at how the gears are assembled. See pic # 4. Watch for the magnet !!
(e)- remove the starter gears on the engine side. You'll need to remove the clips on the gears.
(f) now remove the starter.
3. Slipping Starter (your'e working on the starter only)
You can shim the starter with up to four shims (Yamaha part number 156-11563-00-00) or make your own shim as noted above. I have used 3 shims - maximum. I found that 4 shims makes it too tight. See pic # 2 , it shows where the shims go. Use grease on each shim to hold it in place.
To install the shims;
(a) remove the two long bolts that hold the starter together. You will probably need an impact screwdriver to loosen them. It's a good idea to use a permenent marker on the housing to line up the starter end peices.
(b) remove the electrical end of the starter, carefully. A few taps with a plastic screwdriver handle will loosen it. A lot of carbon dust will fall out. I use a can of compressed air to blow out all the loose carbon. The wiring end of the starters rarely fails.
After cleaning this end, put the cover back one - lining up with your marker lines. Tape the end in place for now.
(c) disassemble the starter nose - there is a small piece of metal in the nose that locks the gears (part #3) - don't loose it, as I did !!! See pic # 5. The starter bolts wont "twist" unless the index clip has NOT been reinstalled---The ring gear back piece has four rabbit ( grouves ) around the perimiter there is a clip that fits in one of these grouves and into a recess in the starter frame--to prevent the twist.
(d) See Pic # 2 for a diagram of the gears in the nose of the starter. Part # 2 is really 2 parts that have been JB welded together.
(e) Some people JB Weld these gears together, or screw in bolt to hold the planetary gear in place. See Pic #6(it has a bolt screwed into the starter casing- bottem right of the pic). This is the same as JB welding.
4. Engagement Problems:
(a) Tension Clip -Gears on the engine side are not engaging properly. Most common problem is weak tension clip. You can tighten the clip with vise grips but just as easy to buy one (under $10). Also check the clip groove (where it sits in the engine casing) This groove can become worn, use a dremel tool to smooth it out.
(b) Install a Washer - You can put a small 2mm metal washer between the idler gears (pic # 2 - between parts 8 & 9). Yamaha has a part # 902-01356-68-00, but my dealer couldn't get one, so I used a metal washer from the hardware store.
(c) Spring - Its always a good idea to replace this spring (again under $10).
(d) Idler Gears - Yamaha redesigned the idler gears (parts 4 & 8 in the diagram). The cogs on the gears are deeper, angled differently and wider. You can't intermix the two gears (old and new together) you have to replace both at the same time. The newer type of gears will only fit the 84+ Viragos.
(e) Crankshaft Gear - the large gear directly behind the rotor/stator hub. This gear is connected to the crankshaft. The gear is turned by the starter idler gear. I've seen quite a few of these large gears with broken or worn teeth. This can cause the clunking sound as the idler gear misses its' engagement with the crankshaft gear.
Replacing this gear is a pain in the ass, but it can be done. You have to use a rotor puller to remove the rotor which gives quick access to the gear.
For starter problems, this is the sequence I use - on older Viragos.
(a) first I would replace the two clips and the spring ($20). As a temporary solution you can use vice grips to gentley squeeze the ends of the clips togther, making a tighter fit on the groove of the gears.
(b) second, JB weld or bolt lock the planetary gears. When JB welding the gears use JB Weld sparingly. I put a small amount along the groove of the lower planetary gear, then press fit the upper gear in place
(c) if these two solutions don't work, then I would add the starter and engine shims and new idler gears..
6. Putting it all back together
Ensure there's lots of grease in the gears in the nose and engine side. Don't use wheel bearing grease, use lithium based. Bench test your starter before putting it on the bike.
To bench test it:
(a) I put the starter in a vise. Secure a cable from the battery negative terminal ( - ) to the chassis of the starter - I use one of the lugs.
(b) Run a power cable from the starter power bolt. Just TOUCH the power cable to the plus ( + ) on the battery, the starter gear should spin. Do Not hold power to the starter, it will overheat!!! 20 seconds is more than enough time. The bench test draws about 2 volts from the battery.
I put the starter back on the frame first, then put the gears back on the engine side. Getting the side cover on can be a pain but patience pays off. A tip to install a new gasket on the engine cover: spray it with PAM non-stick cooking oil. Next time the gasket will come off with no tears!!
7. New Model Viragos ( 84 + )
Newer Viragos 1984 +, use a slightly different system. The starter nose piece shaft is longer, the gear on the end of the starter is completely different and clips are not used with the idler gears. A special bracket is used in its place. Starter problems are not a problem on later models.
8. Starter Repair Service
In the past few years I've repaired over 100 Virago starters. To my surprize most of the problems have been with the armature shorting out. Filing the grooves on the armature and sanding has resurected quite a few starters. If you want your starter repaired drop me an email. I can't guarentee anything until I look at it but I'll give you an estimate of repairs. I charge a flat $50 (US) rate + $10 return shipping.
9. Timing Gear Grinding
- drain oil
- remove the left side engine cover - have a new gasket available. When you apply the new gasket use PAM cooking spray on it. Next time you remove the cover the gasket won't rip.
- remove spark plugs
- using a ruler hold the idler gear in place - simulating the side cover is in place
- just touch the starter button and observe how the gears mesh.
- when you hit the starter button you will see how the starter/ilder gears/timing gear mesh together
There's enough residual oil in the eninge/cylinders for lubrication. It's a lot easier to watch how things work and you'll get a better understanding of how the starter/gears work.
If you have any questions email me at:
Larry's Home Page-North Bay, Ontario, Canada