"The Final Fix" for V 2 motorcycles with "starter problems"

[Isaanbiker]

    

  My apologies, the topic was already posted, I'm afraid without very important details to finally understand why some bikes don't start and where all mechanics would think it's a mechanical problem.

 

It turned out to be an electrical problem that's causing mechanical problems. Sorry for the long post, but it's necessary to read it all. 

 

My special thanks to Michael J. Miller, Texas who’s spent so much time and effort on finding out that the problem of older V 2 Yamaha motorcycles grinding starters and destroyed teeth of the starter mechanism and flywheel weren’t caused by mechanical issues.

 

Even Yamaha didn’t get that far and all they did was to take the spring at the starter mechanism of Gen. I ( before 1984) bikes out. But it didn’t solve the issue and some who did that had very bad luck when the starter mechanism started hanging and destroyed many parts inside the left cover when the starter mechanism didn’t disengage with the flywheel.

 

Mike found out by using an oscilloscope that the voltage drop when the starter engaged was too much and left not enough voltage for the TCI to produce a spark. That on the other hand was the reason for so many people to start (too) many times and (too) long until either the windings of the starter burnt out, wires became too hot, batteries just died and other problems.

 

Then the noisy grinding teeth got worse from week to week and many of these starter mechanisms then destroyed the engine.

 

Mike tried a 12 volt Stabilizer that you can easily find at eBay which doesn’t cost much. If somebody’s interested, I can provide a link for a good quality stabilizer that’s affordable. The cut off point of a TCI = (transistor controlled Ignitor). is 10 volts and if your voltage drops while cranking, then you do not have a spark at your plug.

 

No spark, no running engine and more cranking and therefore more damage to the sprockets and the flywheel will be done.

 

By connecting the “Stabilizer” to the TCI, you basically have constant 12 volts for the TCI right from the battery, a good and strong spark and your bike will start. If the teeth of your starter system and the ones on the flywheel are not yet totally destroyed, such an easy solution will help you to be able to start your bike on the first evolution.

 

Please be aware that this isn’t just a Yamaha Typical problem, basically most classic V 2 motorcycles have a TCI, and the problems are the same.

 

Why does the starter grind? (Gen I starter, Yamaha Virago) MECHANICALLY, the piston travels faster on combustion stroke than the idler, and partially disengages with each revolution. Then fully disengages and grinds. (Yamaha's sole big-piston experience was a kick-start SR500.) ELECTRICALLY, the wide swings of voltage from a weak battery or corrosion in the ground connections will PREVENT the ignition from firing. This fluctuation is milliseconds long, but happens on the compression stroke- precisely when you need the spark.

 

IT happens ALL the time, but is a problem when it drops below 10 VOLTS, the cut-off point for the TCI. Does removing the spring help? 1.Yes, by increasing the mesh of the 2 gears and allowing a few more revolutions before disengagement.

AND- 2. No (if you've been grinding a lot) in that it can cause the idler to hang on the flywheel after starting and cause damage to the starter. RARE, but it happens.(I leave it IN for that reason.)

 

HOW does the stabilizer solve this problem? The Stabilizer guarantees that the TCI fires by providing a stable 12 volts even with a battery that will barely turn the engine! HOW IS THIS THE FINAL FIX? With gears that will initially mesh and crank the engine, the engine will start on the first or second revolution. Like kick starting.

The grinding doesn't happen unless you crank excessively, so treat the bike like a kick start- 1 or 2 cranks, repeat.

 

This procedure will prevent grinding, prevent further damage to gears that are marginal, prevent even having to take the spring out, or ANY of the other 'fixes' offered in the past.

 

It was ALWAYS an electrical problem. A problem that could only be found with an OSCILLOSCOPE. A problem that likely never showed itself in the development of the engine. It CAUSED a mechanical problem.

 

And as it SHOWED itself as a mechanical problem, that's what everyone tried to fix. A good set of gears, a good starter, a stabilizer- and this problem will likely NEVER show. (Yes, you can MAKE it show by cranking until hell freezes over, but most of us were taught to NEVER do that to any vehicle.)

 

Michael J. Miller Austin, TX

 

   Please see it on YouTube: 

[Isaanbiker]

  Here's a dirt cheap stabiliser: 

https://www.ebay.com/i/311627034464?rt=nc&fbclid=IwAR0rTRqywbGJPXUy3QfcuN9NpbRnTvJGPLSz-pyE0zHer2kLHwC89yXGX2E

[canthai55]

1. Use a relay

2. Place a large gauge wire from the battery, thru the relay, to the starter.

3. Hit the switch - Varoom !

Old Jap bikes - or old ANY bikes, need the wiring replaced.

Make improvements as you go to work around the factory garbage.

[Isaanbiker]

7 minutes ago, canthai55 said:

1. Use a relay

2. Place a large gauge wire from the battery, thru the relay, to the starter.

3. Hit the switch - Varoom !

Old Jap bikes - or old ANY bikes, need the wiring replaced.

Make improvements as you go to work around the factory garbage.

Like the old 6 volt VW Beagle that needed a relay to keep the starter working, right. That make sense. 

 

 But this stabilizer is somehow a relay and it stays connected to the TCI to ensure 12 volts (+). 

 

The problem on these bikes is that the CDI doesn't produce a spark when the voltage drops below 10 volts while cranking.

 

And V 2 engines can use a hell lot of juice when starting it with a cold engine.