The autopsy has been performed and the results are in. The starter gear seized up due to material from the starter clutch shim plate embedding itself into the gear shaft.

Here is how I found out:
I decided to drill out the screw from the rotor side. The case hardend screws are M8 x 1.25 and drilled out easy. I drilled completely through the entire length and out the socket head.


I made a jig that suported the assembly on sleeves that passed through the starter gear holes. The idea is to drive the gear off the clutch by striking a drift inserted through the holes drilled in the screws.


Another shot of the jig from the top side showing the drift. It is in the upper right corner near the wrench.


Free at last!! The hammering wasn't too gross but I did have to rotate around to progressively push the gear off.


What happened? Here's a closeup of the starter gear. Look around the outside edges of the central portion.


If the previous wasn't clear, I have marked the area of interest with two red circles. Look between them.


OK. If the previous two are worthless to you, here's an obvious one. The pieces missing from this are stuck in the starter gear. This is the shim plate between the rotor and the clutch. The starter gear was rubbing on the shim plate and grabbed it taking pieces with it. Notice also the "Y" shapes worn where the clutch dogs move.


Here's the business side of the clutch. The Haynes manual shows this from the other side but here you can see the mechanisms clearly. This works fine.


Here's the backside of the rotor plate. As of 12/09 @ 10:15, I am still picking drilled out threads from the rotor. Such is life for an anal, frustrated machininst wanna-be.


So that's it. Now we all know why the poor starter motor was killed. I guess that Starwalt's Disease needs more detailed definition. If your starter gear seizes on the rotor/starter clutch assembly due to starter gear shim plate interaction, you have Starwalt's Disease.

Thank you for your attention! Refreshments are being served in the lobby!

hm.  What made the two contact each other in the first place, I wonder..

Wowee .... good job ... starter gear getting eaten and making the starter clutch not dis engage and taking the starter for a 1,000,000 rpm ride ... = Startwalts disease... whooo hooo... I had forgotten that the bolts come through to the rotor side with their tail end ... but good you drilled there ...
I will now take mine apart when the damn place will stop raining ... and look for it ... I had a new everything ... especially a totally new starter clutch and near new engaging gear but it still clunked last week... WTF ... I cleaned everything to the point my wife wanted me to sleep with it ...  :x
Cool.
Srinath.

Quote from: seshadri_srinathWowee .... good job ... starter gear getting eaten and making the starter clutch not dis engage and taking the starter for a 1,000,000 rpm ride ... = Startwalts disease... whooo hooo... I had forgotten that the bolts come through to the rotor side with their tail end ... but good you drilled there ...
I will now take mine apart when the damn place will stop raining ... and look for it ... I had a new everything ... especially a totally new starter clutch and near new engaging gear but it still clunked last week... WTF ... I cleaned everything to the point my wife wanted me to sleep with it ...  :x
Cool.
Srinath.

maybe you have goats again... I'm still stuck on my bent case cover theory.

I will look carefully this time at the case cover ... Starter clutch is my guess though ... case cover will make a noise at all rpm all the time ... this sounded exactly like the sledge hammer from the inside I was used to hearing when my starter clutch was bad.
Cool.
Srinath.

In retrospect I should have used a bit just larger than the drift diameter. That way the screws would have been intact, the drift would still get to the starter gear, and I would not STILL be working on getting the freakin drilled out screws from the rotor!  :x

Past experience had the screw material falling out of the drilled out fastener but not this time.  :guns:

Oh well.

Quote from: se7enty7hm.  What made the two contact each other in the first place, I wonder..

My question exactly. I see nothing in the parts listings to show they do or do not. If they do, one would think there would be a roller bearing to keep the affect I found from happening. I suspect they should not.

After I get the rotor and starter gear cleaned up, I plan to see how much they play together. There was some junk inside the crankshaft after I pulled the retention bolt out. I suspected it was old loctite or somesuch thing.

In my starter clutch ... there were distinct teeth type marks on the engagement part of that starter gear ... somehow the starter clutch seems to make small bite marks as it engages.
Cool.
Srinath.

Quote from: seshadri_srinathIn my starter clutch ... there were distinct teeth type marks on the engagement part of that starter gear ... somehow the starter clutch seems to make small bite marks as it engages.
Cool.
Srinath.

hmm..


my bike didn't make any noise.. it made a 'clunking' noise the first time I started it.. then never again..

Yea sometimes it will clunk a bit on startup, and then never, but a bent case might make it scrape more than just 1 time, now mine when it was dead .... made serious scraping noises most of the time at low speed...
BTW the noise is loud and the vibes through the bike and bad that instant.
Cool.
Srinath.

The rotor is now clean!  

I went by my machine tool place and told him my problem. The 6.8 mm drill bit I bought did the trick. I had not used a large enough bit to removed enough material for the tap to bite.

I drilled out the remnants of the old screws. The 8mm tap did the rest.

Now to clean up the starter gear and try to analyze why it decided to chew on the shim. The shim must be replaced but the starter gear may be OK.

Wowee man ... you just blew my mind ... I swapped out rotor, gear, clutch and everyhitng but never checked if the engagements were right ... now I better open it and check, and where is the specs written up ... manual??? clymers haynes
I better get on the horn and kick the dude that's got my manual for the last 6 months ...
Cool.
Srinath.

Quote from: seshadri_srinathWowee man ... you just blew my mind ... I swapped out rotor, gear, clutch and everyhitng but never checked if the engagements were right ... now I better open it and check, and where is the specs written up ... manual??? clymers haynes
I better get on the horn and kick the dude that's got my manual for the last 6 months ...
Cool.
Srinath.

engagements were right for what? between what gears?

The starter clutch engaging and dis engaging is what I was referring to not drive gears ... Now the shim os on the back of the magnet and they want the clutch to grip the gear at the right place ... to faar off the end and it might 1/2 bite and wear, too far in and OK no idea ... but hit the vertical face of the gear maybe... so ... the shim was the right thickness to let that happen ... I didn't check mine ... worth trying since my problem seems to have shown up again.
Cool.
Srinath.

Quote from: seshadri_srinathThe starter clutch engaging and dis engaging is what I was referring to not drive gears ... Now the shim os on the back of the magnet and they want the clutch to grip the gear at the right place ... to faar off the end and it might 1/2 bite and wear, too far in and OK no idea ... but hit the vertical face of the gear maybe... so ... the shim was the right thickness to let that happen ... I didn't check mine ... worth trying since my problem seems to have shown up again.
Cool.
Srinath.

I didn't notice or check mine.. hmm

Yea I know neither did I ...
Cool.
Srinath.

Srinath is talking about the clutch rollers, "dogs" by my name, and the small indentations they leave on the starter gear shaft. Each time you start the motor and they engage, they leave 3 rectangular depressions across the face of the starter gear shaft. This is just a fact of engagement and material strength. These depressions are in line with the crankshaft. The crankshaft leads me to my next paragraph.

The starter gear has a brass liner with a hole and machined channels for the distribution of oil that is sourced from the hole in the crankshaft. If insufficient oil exits the crankshaft hole, insufficient oil gets into the channels. Not enough oil in the channels, not enough oil to prevent the starter gear from getting cozy with the shim or the opposite side of the starter gear and the crankshaft. IF a suffciently small particle escapes into this oil delivery system and gets between the starter gear and the shim...munch, chew, chomp.

As the crankshaft turns, and assuming oil pressure is correct, a spurt of oil will be delivered into the channels when the two holes line up. Remember that the starter gear should be at a near standstill after the motor is running. The crankshaft is turning inside the brass liner after ignition. The slight mechanical resistance of the starter motor is all that keeps the starter gear from freewheeling with the crankshaft due to fluid resistance (think torque convertor).

With my starter gear on the crankshaft, I have a little "play" between the crankshaft and the brass liner of the starter gear. How much is too much? Clymer does not say.

I think my failure was due to insufficient oil delivery to the outside of the starter gear and the shim. The oil pump and pressure is way first on my list of things to check after I get this part of the engine assembled.

Just picked up an issue of a Brit Cycle magazine - Classic & Motorcycle Mechanics. They are rebuilding a GS750 engine. I missed issue 202 August and don't know the whole story. These guys are welding broken fins back and really pulling out the stops. Issue 204 October shows that at one time Suzuki used roller bearings under the starter gear. It also mentions a bronze thrust washer for crankshaft-wise movement reduction.

From 204:
"The generator rotor fits on a taper on the crank end and is usually bullet-proof - some bikes do suffer from the rotor coming loose on the taper end and, if there's any sign of problems here, I'd lap the tapers in with a little grinding paste before assembling."

Some form of thrust washer wouldn't be a bad thing if I knew that oil could get between the clutch shim, the washer, and the starter gear.

Issue 203 has a couple of good shots of the starter gear and clutch.

The mag is a little expensive and I can only find it at Books-A-Million. Of course it does have to come a long way to my shelf.

I've got photos of the starter gear operation over in the FAQ section now. Whoooeeee! If my mom understood me, she would be impressed. Come to think of it, my kids don't understand me either. Oh well.

Quote from: starwaltSrinath is talking about the clutch rollers, "dogs" by my name, and the small indentations they leave on the starter gear shaft. Each time you start the motor and they engage, they leave 3 rectangular depressions across the face of the starter gear shaft. This is just a fact of engagement and material strength. These depressions are in line with the crankshaft. The crankshaft leads me to my next paragraph.

The starter gear has a brass liner with a hole and machined channels for the distribution of oil that is sourced from the hole in the crankshaft. If insufficient oil exits the crankshaft hole, insufficient oil gets into the channels. Not enough oil in the channels, not enough oil to prevent the starter gear from getting cozy with the shim or the opposite side of the starter gear and the crankshaft. IF a suffciently small particle escapes into this oil delivery system and gets between the starter gear and the shim...munch, chew, chomp.

As the crankshaft turns, and assuming oil pressure is correct, a spurt of oil will be delivered into the channels when the two holes line up. Remember that the starter gear should be at a near standstill after the motor is running. The crankshaft is turning inside the brass liner after ignition. The slight mechanical resistance of the starter motor is all that keeps the starter gear from freewheeling with the crankshaft due to fluid resistance (think torque convertor).

With my starter gear on the crankshaft, I have a little "play" between the crankshaft and the brass liner of the starter gear. How much is too much? Clymer does not say.

I think my failure was due to insufficient oil delivery to the outside of the starter gear and the shim. The oil pump and pressure is way first on my list of things to check after I get this part of the engine assembled.

OK I should check for oil pressure as well ... BTW You know how to make a oil pressure guage ...
There is a chrome plated bolt on the right bottom of bike that is a direct block off on the oil galley ... take it off and drill and tap it to take a banjo bolt, then banjo bolt and run a #3 line to the oil pressure guage ... which is a standard auto parts item, buy good quality ... like a auto meter ... my cheap ass guage blew and sprayed my right side and a goodly portion of I-5 south of sacramento with 20W50 (Between elk grove and the next exit for those that know ... on a fateful day back in 1998 triggering a series of events that resulted in my wife rolling the truck 3 hours later, 2 weeks before we were to set off for Canada with all our lifes possessions in tow) ... but I digress ...
Cool.
Srinath.

Let's leave the engine for a little while and look at another area of the bike. I noticed the handle bars were bent and removed them. I will deal with the handle bars on a later post.

After I got the bars off, I noticed something about the fork tubes as they come up the top piece. See if you notice too.



What's up with that? Impact damage?
If it is not obvious to you, notice the tube on the right (left fork tube) pokes up about an 1/8" farther than the tube on the left (right fork tube).

New sub-topic. Go!