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Matt P's Flywheel Issue

Question for any geometry wizards: If the pattern is flipped over, how many degrees would the timing mark move?
Just as a WAG, let's "assume" it would move by 144 degrees, two bolt holes' worth.

I think it would depend on which axis you flipped it and where the timing mark was relative to that axis.
 
I want to clarify

I want to make it clear, I have nothing against Matt, nor his troubleshooting.

He is one of the best in the business.

I made my comments based on the conversations in this forum regarding flywheel alignment.

Could BMW made the flywheel differently with a key or pin? Yes, they could have but they did not. Could repair manuals/instructions be better, Yes, they can. I have seen You tube videos of repairs that were outstanding. At the same time, I have seen some that were useless. Same with printed manuals.

I stand by my comments regarding some people's actions when making repairs or doing maintenance. Some people should NOT be working on engines.

I have seen new guys make mistakes out of ignorance, I have also seen guys with years of experience make mistakes out of ignorance or carelessness.

Taking an engine on an Airhead apart to change a main seal is not all that difficult, if a person follows the correct methods of doing the job.

If someone cannot take the time to put the flywheel back in the proper position it was in when it came off, I most certainly do not want that person working on my bikes. Same goes for blocking the crankshaft so it does not shift and loose the shim.

I am looking forward to Matt's article explaining what in fact the problem turned out to be. St.
 
By "flipped over", I'm referring ONLY to the front and rear faces. THAT is the overall question.
 
But it seems to me that the fact that the bike was running up in the mountains, was dropped, and then ridden back from the mountains before quitting near Matt's house should suggest that nothing mechanical about the flywheel is wrong...at least the way I read it. That ride back from the mountains had to be a good 15-20 iles. Matt's in Colorado Springs and while the mountains are visible, the roads too and from have to cover some distance.

I think one can put the flywheel back on in any orientation as long as the timing marks are adjusted accordingly. The flywheel is just a mass as well as something that carries the teeth for the starter to mate with. It doesn't really have anything to do with when the spark fires.
 
By "flipped over", I'm referring ONLY to the front and rear faces. THAT is the overall question.

I probably am not seeing this visually right. So you're looking at the rear facing part of the flywheel, hand hands holding it at 3 and 9 o'clock. Flip it around the vertical axis so that the 3 o'clock position becomes the 9 o'clock position. You're now looking at the formerly forward facing part of the flywheel. But what if you flipped so that 12 o'clock went to 6 o'clock. Wouldn't that be different? Especially if the timing mark was initially at say the 3 o'clock position, or the 4:30 position, or... Obviously, the 5 bolts have something to say about where it can be flipped to.
 
Makes me wonder what (else) was happening when the Enduralast ignition was installed, how was the timing set?
And you take us right back to the original question... and IF it can be flipped over, that gives you ten possibilities instead of five.
 
I don't have a clear picture of the flywheel of my '89 R100GS. But I think this picture shows that the front and back sides are different and you cannot mount it with the wrong side facing you.

DSC02255sm.JPG

/Guenther
 
I don't have a clear picture of the flywheel of my '89 R100GS. But I think this picture shows that the front and back sides are different and you cannot mount it with the wrong side facing you.

View attachment 76265

/Guenther

Yes. The clutch carrier (flywheel) is dished and only one face can be mated to the end of the crank. Matt’s article indicated that he verified that OT on the flywheel was in the window with pistons at TDC. He also verified that neither the crank sprocket nor the cam sprocket had sheared their woodruff and spun on their respective shafts, and after reassembling the engine set valve clearances which would again be done using the OT marking on the flywheel. So I think it’s safe to assume the crank, cam, and valve train are in their correct relationships.

It seems the problem as it presents now is one of ignition timing, not valve/piston/flywheel relationships so I’d tend to agree with the opinion expressed by 20774 that it’s an electrical/ignition issue. Bean cans were swapped, to no avail, and the bean can only fits one way due to the offset on it’s engagement tab. And the corresponding slot it engages could only be off if the crank and cam sprockets were not properly aligned on assembly—and Matt verified those marks. That leaves coil and ICU as the next items in the chain, and while we are used to seeing these items fail suddenly, usually after a period of presenting intermittent issues, certainly other failure modes could be possible.

Definitely a good puzzle and one I trust Matt will successfully solve. Can’t wait to hear the final diagnosis and solution.

Best,
DeVern
 
93 is too new for me to have had the parts in my hands - my newest is 1980 R65 with bean can points

Everyone commenting here seems to be focused on the rear end of the engine

I ask this as food for thought for those who have actually had the pieces in hand:

How does the front end of the camshaft drive the bean can?

Is there any way for whatever fittings are affixed to the front of the camshaft to be loose or have slipped
relative to the actual position of the cam lobes?

Is the camshaft one piece of machined metal or is the front narrow part made separately and heat fitted
into the larger rear part with the lobes?
 
I just happen to have a new camshaft on hand, just waiting for time to get at that particular project. I can verify that yes, the cam is a billet piece and not built up. Also noted the slight offset of the slot that drives the bean can; that offset pretty much guarantees the bean can cannot be installed 180 degrees out of phase with the camshaft.

Best,
DeVern
 
THANK YOU GUENTHER!!! :thumb (And yes I've verified that the 87 to 90 R100 uses the same part as the 91 to 95.)

I was going to ask if the factory machined both sides equally (which would facilitate a flip-over), but that's answered now too.

Thanks again!

Now to wait until Matt gets back from Europe...
 
I've been flowing this with interest as I have a airhead.
I hope this is not something as simple as it just ran out of gas..
 
Received the April issue yesterday (and enjoyed the multiple sniglets in Bill's page), and it seems that Matt hasn't found the real gremlin yet...

So here's another proposition: We know that a few bikes had their flywheels installed incorrectly, being rotated by one or two bolt holes (@ 72 deg each) ... Is it possible that this particular wheel was manufactured incorrectly, in that it got flipped over to "wrong side up" when the timing mark(s) was (were) applied? This would give the effect as noted in my initial post. Or maybe it was right side up and the person or machine that made the mark(s) just goofed.

The only way to check this would be to compare it side-by-side with a "known good" flywheel (don't mix 'em up!). Certainly the likelihood is "quite low", but just maybe...?
 
The funny/strange thing is the bike was running down the road when it shut off.
Flywheel whacked out or not, the thing was running.
This is odd Matt Parkhouse can't figure it out.
If you got gas and compression you need spark, looks like a electrical problem from my easy chair, way up in the cheap seats.
 
Nick, you're absolutely right.

:banghead :banghead :banghead :banghead :banghead

Beat me repeatedly with a heavy pointed stick, call me Pinata.
I went back and saw on page 32 that after he re-mounted the flywheel, it started right up; then in the December issue on page 36, it was running until shortly after the owner dumped it.

So yeah, it looks like an ignition issue.

Guess I owe everybody a beer.
 
He has figured it out

In the latest MOA "Keep Em Flying" Matt discloses what the problem was with his GS fly wheel, timing mark problem was. You gotta read it. After all that diagnosing and tear down it turns out it was the Starter that caused the problem and messed with his diagnosis procedures. It just goes to show that even one of the best and most meticulous in the business runs into a head scratcher with a simple but almost impossible to believe resolution. Who would have thought!
 
When Matt wrote that it was the starter I thought, "how, what, why". When I read further exactly what it was about the starter I just shook my head in amazement. I would not have guessed that in this lifetime or the next. Some things are just too weird not to be true.
 
Just now picked up the magazine out of the mailbox - WOW... That's a new one on me too. :bow
Glad he not only got it sorted out, but that the information was shared with the rest of us! :thumb
Way to go, Matt! Good on ya!
Paul S
 
Backward starters

Not bike related but I know of someone who damaged a boat engine because they installed the port starter onto a starboard engine. Cranking the starter ran the engine backwards, it sucked water into the exhaust an hydro locked it. On this boat, one engine turned clockwise, the other counterclockwise.

Strange things happen all the time. Matt, got bit by the one in a lifetime problem. Glad to know he found the problem and could fix it. St.
 
For those who didn't see the article, the starter was spinning the engine the wrong direction....
 
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