My 1974 R90/6 never-ending project, with plenty of pics.

[James.A]

Nathan, I see another trip to your shop in the near future.

How about this,.... I bring my last spare starter and the matching flywheel and we install them and see what happens?

 

[crazydrummerdude]

That sounds like a good time, actually.

You know, it's a shame it's got to this point again. I was hoping I'd ride up to your place and pay you back for the parts/help.

I'm going to start counting teeth on my flywheel/starter, and report back.

Unfortunately today (yesterday), I got too carried away with my Model A to make much progress on the R90. I did give it the stink eye, though.

 

[James.A]

That sounds like a good time, actually.

You know, it's a shame it's got to this point again. I was hoping I'd ride up to your place and pay you back for the parts/help.

I'm going to start counting teeth on my flywheel/starter, and report back.

Unfortunately today (yesterday), I got too carried away with my Model A to make much progress on the R90. I did give it the stink eye, though.

Stink eye,...nyuk,...nyuk....nyuk....nyuk.

Let my know what you find,...heaven forbid that we should have to call in Randy Boris on this one.

 

[manicmechanic]

Which size hammer would you want me to bring?

 

[69zeff65]

Time well spent

The time you have spent is gone now, but you may want to consider taking the time to pull the transmission and give that flywheel a real good inspection. You may even find a loose chunk of the first starter floating around in there and that caused the second ker-chunk.

 

[James.A]

The time you have spent is gone now, but you may want to consider taking the time to pull the transmission and give that flywheel a real good inspection. You may even find a loose chunk of the first starter floating around in there and that caused the second ker-chunk.

I agree that the time has come for Nathan to pull the transmission and clutch to have a good look. The way that the flywheel fits up to the crank, it's not likely for the thing to exhibit a run-out concentricly. It is concievable that if some of the flywheel bolts are loose or sheared that the flywheel might flex or wobble, especially at the instant where the motor tries to fire. You might not be able to see that sort of thing when turning the motor over with the kicker.

The thing to remember here is that the whole problem surfaced out of the blue and blind-sided our young friend. There would have been no broken bits to interfere when the first starter broke.

 

[dennisdarrow]

Strange indeed...........Seems odd that the starter originally was dragging which should have nothing to do with breaking the nose........and then, now after dragging had stopped the nose starts breaking.....Neither problem should be related and if I remember correctly without rereading the nose broke BEFORE going in and working on the oil pump........Surely one would have eyeballed the flywheel before, during and after that job before buttoning it up...........

NOT to put work on you Nathan......BUT......if you pull the transmission, while it is pulled, put in a starter system, (take it over to a starter motor repair shop and get them to check it out and freshen that nose), pull the plugs, hook up a jumper battery, and run that puppy again and again..........Just thoughts and God bless Bud.......Dennis

 

[crazydrummerdude]

Which size hammer would you want me to bring?

if I remember correctly without rereading the nose broke BEFORE going in and working on the oil pump

Nope, after. The bike was my daily driver last fall.

I agree that the time has come for Nathan to pull the transmission and clutch to have a good look. The way that the flywheel fits up to the crank, it's not likely for the thing to exhibit a run-out concentricly. It is concievable that if some of the flywheel bolts are loose or sheared that the flywheel might flex or wobble, especially at the instant where the motor tries to fire. You might not be able to see that sort of thing when turning the motor over with the kicker.

The thing to remember here is that the whole problem surfaced out of the blue and blind-sided our young friend. There would have been no broken bits to interfere when the first starter broke.

The old familiar sight.

Turn your back to it for one second, and the Airhead Gnomes will take it apart on you!

The flywheel doesn't budge. Nothing's obviously wrong. There's either some Airhead Gnome Dust, or some of what used the be the starter sprinkled around. Not too much, and you can't really even feel it.

Almost all the teeth look like:

That is to say, presumably fine.

The only not-good part is:

..and to me, that doesn't look too terrible.

I was told to start counting teeth. There are 8 on the starter. I'd guess and say there's 95 on the flywheel. I didn't realize that while I was turning it to count them, I was wiping off all the marks I was making.



Still in the dark.

Oh yeah, I did install new choke cables, though. You gotta watch out for this little ball when you take it apart.

 

[mymindsok]

I'm gonna check my parts stash tomorrow night to see if I have a FW thats better than the one you have.

I don't like the looks of those teeth. Someone else might think that theyre perfectly ok but the last time I fracked a starter...

 

[crazydrummerdude]

I'll admit, the teeth look worse in the pictures than in person.

 

[lonerider]

common factor

Two starters almost identical breaks
First starter worked for years
Second starter failed upon installation
Common part: flywheel.
Find the problem. You can see the symptoms.
I once saw a blue shop towel try to pass between running gears.
It broke a case that was thicker than a starter nose housing.
An object could still be wedged between teeth on the flywheel.
If they was no object in the bottom of the bell housing, I would
scrape between the flywheel teeth with a small screwdriver or an awl.
Was the timing hole plug in place when the first starter failed?
Good Luck
The Lonerider

 

[crazydrummerdude]

Two starters almost identical breaks
First starter worked for years
Second starter failed upon installation
Common part: flywheel.
Find the problem. You can see the symptoms.
I once saw a blue shop towel try to pass between running gears.
It broke a case that was thicker than a starter nose housing.
An object could still be wedged between teeth on the flywheel.
If they was no object in the bottom of the bell housing, I would
scrape between the flywheel teeth with a small screwdriver or an awl.
Was the timing hole plug in place when the first starter failed?
Good Luck
The Lonerider

But, this flywheel worked for years, too. As it is, I introduced another common part; the solenoid. At catastrophic failure, woodnsteel's starter was equipped with my old solenoid.

Timing hole plug was in place. All the teeth appear to be free of FOD.

Could it be that:
my solenoid broke my starter,
woodnsteel's starter had a wonky solenoid,
my solenoid replaced the wonky one, and broke in turn broke his starter?

I'd love to be able to afford to throw money at the situation and try a brand new, super expensive (I mean, fancy) starter, but I really don't have faith that the problem lies within my solenoid, let alone any other single item (at this point).

 

[Bill Burke]

ok, something is clearly out of alignment. the break is consistant with excess pressure on the nose cone ( had this problem with early HUMVs in the army )for some reason, your starter is too close to the flywheel, so that when you activate the solinoid, it applies too much pressure to the nose cone, causing it to shear.is your flywheel off center/the wrong size/somehow abnormal?possible WECSOM ( Wiley Coyote School Of Mechanics ) solution, weld up nose cone, bore out mounting holes on starter to move it farther from the flywheel?random thoughts at 3:30 in the morning.

Roguetek may be on the right track. See discussion on "interference problem" (with fix pics) about halfway down in this Snowbum article:
http://bmwmotorcycletech.info/boschvaleostarter.htm

 

[James.A]

Roguetek may be on the right track. See discussion on "interference problem" (with fix pics) about halfway down in this Snowbum article:
http://bmwmotorcycletech.info/boschvaleostarter.htm

Bill, I gree with you and Rougetech that there is certainly an alignment problem here. The fact that It showed up after 3300 miles of no problems is, to me, the sticky detail. What makes a bike that has a few thousand miles of service, all of a sudden start breaking starters? Something HAS changed. The question is why?, or what?

 

[crazydrummerdude]

Bill, I gree with you and Rougetech that there is certainly an alignment problem here. The fact that It showed up after 3300 miles of no problems is, to me, the sticky detail. What makes a bike that has a few thousand miles of service, all of a sudden start breaking starters? Something HAS changed. The question is why?, or what?

Exactly. I mean, the flywheel feels secure. The starter was secure.

I can't wait to look back on this in a year and be like; oh, that was so simple.

 

[Bill Burke]

Nathan-
I haven't gone through all the posts on this great thread you've created, so I don't know if you've rebuilt the engine. The reason for my question is compression. Is it really high for some reason (starter can't overcome torque on compression stroke forcing starter backwards, breaking cone...).

 

[crazydrummerdude]

Of all the tools in my shop, I don't have a compression tester that will fit my motorcycles. So, it is unknown.

I presume the engine has decent compression, though; new rings/freshly honed.

 

[mikeb921]

But, this flywheel worked for years, too. As it is, I introduced another common part; the solenoid.

Could it be that:
my solenoid broke my starter,
woodnsteel's starter had a wonky solenoid,
my solenoid replaced the wonky one, and broke in turn broke his starter?

I think you may be on to something here. Since you've inspected the flywheel ring gear, the solenoid should be thoroughly checked out as well. The breaks in the 2 nose cones are so similar. Check the solenoid for a bent part that may allow it to slam the starter gear a little too far forward (or backwards in this case). Yes, I'm grasping at straws but I can only inspect it with "your" eyes.

Ride Safe
Mike

 

[James.A]

Nathan, I have pulled all my spare parts out of my back-shed. When do you want to have a "tech day"? I'm thinking that the next starter and flywheel I can supply is from a 1978, R80. I do have a 1976 Bosch starter but not the matching fly wheel. I also have a few examples of starter relays. The big question would be " what do we try first"?.

 

[crazydrummerdude]

Nathan, I have pulled all my spare parts out of my back-shed. When do you want to have a "tech day"?

Saturday?