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Matt P's Flywheel Issue

I'm not sure

I am not sure because as I have said, I am too lazy to go back in the issues of the magazine to Matt's original articles mentioning this problem but I think the stater on the bike broke when the owner tried to start it after it hydolocked or broke down.

Matt replaced the stater with one he had on hand unknowing it was a Frankenstarter, part airhead part oil head. The biker only cranked backwards after Matt had done extensive repairs on it due to the original problem. The bike would not start would crank, would not align timing marks after the work done, leaving Matt very perplexed.

This month's issue has in it how he found the problem, what the problem was and an run down as to why thing went the way they did.

This thread like all threads has been a hoot to read, and covered a lot of things pertaining to Matt's problems as well as other things. Only in the MOA forum could this happen we go from a missing timing mark, to backwards flywheels to sinking boats. A very diverse crowd of members we are indeed.

Cheery bye, St.
 
Paul -

Have you timed or checked engine timing that way? By cranking the starter?? This is the first time I've heard of that...never would have crossed my mind. As we know there are ways to check for static timing. Normally one would just then hit the starter button and then fine tune the timing with engine running. Clearly the engine never started that way. But still, Matt would have confirmed the basics that the ignition is properly timed...too bad, it appears, that the use of the starter might have taken him down a rabbit hole. Just bump start it and go from there. :scratch
 
perhaps Alice

Kurt, the rabbit hole is it seems when static timing was done, everything looked good. From Matt's point and knowledge of the work he did then redid to confirm his work and make sure he didn't miss anything, the bike was excellent. It would be, I bet he was turning the engine by hand doing static timing and I bet he was turning it in the correct direction. So, the timing would work spot on perfect because the engine and ignition system was happy it was going in the right direction. Along comes Mr, Frankenstarter, who spins things the wrong way and suddenly the ignition won't fire, the bike won't run, the timing marks won't line up.

Now I have seen an airhead engine run many times with the front engine cover off but I never could determine just by looking at it what direction it is turning in. I am sure a method can be found to show when the starter is cranking over the engine just which way it is turning, but that was not the case here. Matt knows the direction the engine should turn, once it greats cranking by the starter motor unless the aforementioned steps are taken to determine proper direction, I thinks most people would assume it was cranking in the proper direction.

Man oh man, Matt is not me!! About the second or third time I tried to get the bike running, it would have melted in my anger and wrath. The sky would have been blue with my use of the vernacular. LOL,

Some mathematician should figure out the odds of this happening to Matt. Like I said, bad it happened to him but since he beat the odds and found/solved the problem, he should have bought a lottery ticket. He can then travel to Mexico and Europe, wherever in first class.

Cheers, St.
 
Mystery solved for me

Re-reading Matt's recent article, he said he installed "another" starter after he received the bike. This was the type for an oilhead.

This was the missing link. The previous owner never used that starter.

/Guenther
 
missing link

Matt had purchased this starter unbeknownst to him it was a frankenmotor. Hence he says he will check more carefully in the future.

The missing link is why in the world would someone piece the stater together with the wrong parts and sell it as a good proper unit? If it is the Valeo factory, shame on them. If it is someone on the internet selling on Ebay or other sources, shame on them.

Matt is twice blessed in he didn't damage the engine cranking it backwards, and he was able to solve the problem without ending up in the nut hatch. St.
 
Question for Paul G - Paul, I'm having trouble understanding your second statement in Post #59, that the timing light would indicate when the points were closing instead of opening. Certainly the "change of light" would appear to happen at the wrong time, but the lights - whether static or dynamic - are designed to show when the spark happens, which is when the points open, and the instrument doesn't care about direction of rotation. Indicating the "closing" would seem to be reverse logic applied to the light. Could you please clarify this?
Thanks!
PaulS
 
Question for Paul G - Paul, I'm having trouble understanding your second statement in Post #59, that the timing light would indicate when the points were closing instead of opening. Certainly the "change of light" would appear to happen at the wrong time, but the lights - whether static or dynamic - are designed to show when the spark happens, which is when the points open, and the instrument doesn't care about direction of rotation. Indicating the "closing" would seem to be reverse logic applied to the light. Could you please clarify this?
Thanks!
PaulS

I may well have mis-stated what I was trying to say. So I will try to clarify.

I will make up some numbers here, but imagine the profile of a cam lobe rotating clockwise. Somewhere, say 30 degrees to the right (clockwise) from the center of the cam lobe the points will start to open. The ignition will fire. They will stay open as the cam rotates past the center of the nose and then will close let's say 30 degrees after the point rubbing block is at the center of the cam nose.

When rotating in this normal fashion the crankshaft will be the specified advance before TDC when the points open and the ignition coils fire. The piston will be somewhere well past TDC when the points finally close.

If you rotate the engine backwards the crankshaft and piston will be in the position where the points normally close when they open. Indeed the ignition fires when the points open but the crankshaft and piston are in a position that will not allow the engine to run. Which is, I think a good thing.

I don't have enough data to even try to figure out the positions of the intake and exhaust valves but would suspect that since this is at a point in the power stroke shortly after ignition that both valves are probably closed.
 
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For completeness' sake, the R100GS has the HES ignition, not points, but it behaves pretty much the same.

The Oilhead and Airhead motors turn the same say, but the starters are mounted facing different directions (therefore have to turn different ways) and they have unique nose cones. I have a box of dead starters and starter parts, and if I wanted to I could easily mismatch a starter when making one from parts. The magnet housing defines the direction of rotation. "Fixing" a starter by using a magnet housing from the wrong starter would do what Matt experienced. It's not such an issue in real life as the magnet housings are the parts that typically go bad first, but clearly it can happen. I probably have a starter or two that have bad solenoids and would have good magnet housings that could be donated to revive another. But I don't fix them anyway; I buy new Valeos from EME. If anyone is passing through Charlottesville and wants a crate of good and bad Valeo and Bosch starter parts, let me know.

I have no idea at what point I would have figured it out myself! Looking forward to reading that article.
 
I have no idea at what point I would have figured it out myself! Looking forward to reading that article.

Probably a lot sooner than I would have. I already confessed I would not have guessed this during this lifetime or my next. :)

However, next time I hear a tale of really weird ignition timing I might remember to ask if the engine is turning backwards.
 
All of us

Yes, all of us here in my neck of the woods have filed this one away. I printed the article out for The Beemer Barn's files. Seriously, what are the odds it could happen and what are the odds it could happen again.

Matt should have bought a lotto ticket the day he figured it out. If he has another one show up, He should definitely buy a ticket. LOL. St.
 
I went back and relooked at the beginning of this issue for Matt. As we have read, a GS rider dropped the bike and it was on its side for 5-10 minutes which let some oil into the combustion chamber. When the rider tried to start the bike, he experienced hyrdo-lock and the bike wouldn't start. A friend realized what was going on and got the oil drained and then bump started the bike. Bike ran OK, but from what Matt wrote, the bike didn't quite make it back to Matt' place but a block away.

Matt began to trouble shoot things. Figuring that the starter needed overhaul, he found the original Valeo starter with a damaged Bendix mechanism. He had an R1150R Valeo starter so he wrote he transferred the "motor part" from the Oilhead starter to the damaged Valeo. He then used the starter to spin the engine with spark plugs grounded and saw good sparks. At that point, the bike wouldn't start. Not having a running engine, it appears that he used the starter to check the dynamic timing but as we now know, the timing was "off". Lots of other things ensued to find the problem, plus he asked other folks including Tom Cutter for ideas to look into.

He also said that he checked compression with the faulty starter and the numbers looked good. I'd have to think about it but is compression still built up when spinning the engine backwards? :dunno

Since reasoning and his efforts to that point said that everything was OK, it must be the starter. He purchased a new starter from EME and the bike started right off! That led him to do some bench tests on the original starter (with the replaced motor part) and a Bosch starter he had. That's when he saw that the "repaired" Valeo spun the opposite direction.

EME told him that indeed the motor part of the starter was identical but spun opposite directions. We know this has to be since the starters are oriented differently in Airheads and Oilheads but the engine rotation is the same way...thus the need for different spins on the starter.

So, I'm left questioning what the "motor part" of a starter is. I've never been that up and close to a starter out of a bike, so I don't really now the details. My simple ideas were that the windings of the rotor would spin the armature and that the Bendix moved the rotating armature (with splines) out to engage the flywheel teeth. Seems to me that the windings of the starter motor would cause the armature to turn one way or the other...not the Bendix. Again, I don't have a good concept of exactly what is going on.

Also, I guess Matt learned as the rest of us that this "motor part" did different things. He said he had an Oilhead starter and used the "motor part" from it assuming it did the same thing as they all do, and that it was compatible with all starters. I wonder what told him that this spare Valeo starter he had was specifically an Oilhead starter.
 
...why in the world would someone piece the stater together with the wrong parts and sell it as a good proper unit? ....


My 93 R100GS/PD came with the Valeo starter. Some years back the bike failed to start. I was able to bump start the bike and get home. I subsequently found that the Valeo starter failed due to the glued-in magnets coming loose. This was a common problem with airheads using these starters. One solution was to visit a local auto breaker (junkyard) and obtain a Saturn (car) "short" starter. This was a Valeo starter, but it was necessary to remove the car's starter "nose" or front end and swap it for the airhead starter front end.

I was still concerned about the potential for glued-in magnets failing so I obtained an old Bosch starter and used that for a while. Eventually I went with a Nippon Denso starter sold by Rick at Motorrad Elektrik. Both the ND and Valeo starter use planetary gears to allow the starter to spin with less battery strain. The Bosch starter had to work hard to start a cold bike.

If I had obtained an oilhead Valeo starter from a breaker I'd likely have made a similar error.
 
Kurt, go back to page 36 of the September issue - the "motor part" is the larger black cylinder on the assembled airhead starter (the smaller cylinder being the solenoid), and also the separated cylinder of the disassembled oilhead starter (with the silver sticker showing).

I don't know if the gears inside the nose assembly are manufactured with different angles to achieve the different direction of rotation (and I doubt that the tooth count and pitch is the same, since they have to mate to different bikes' flywheels), but it would be easy for the motor's manufacturer to interchange the connections to the motor's windings to have it spin "the other way". (I only have one spare old oilhead starter in the garage right now, so I can't directly compare them.) In Matt P's talk with Matt Normann, he does say that the part that interfaces with the flywheel is very different.

As long as there is a period of engine rotation when both valves are closed, yes there is compression. I don't know if it would be the same as normal, since the cam timing has changed.
 
Kurt, go back to page 36 of the September issue - the "motor part" is the larger black cylinder on the assembled airhead starter (the smaller cylinder being the solenoid), and also the separated cylinder of the disassembled oilhead starter (with the silver sticker showing).

I don't know if the gears inside the nose assembly are manufactured with different angles to achieve the different direction of rotation (and I doubt that the tooth count and pitch is the same, since they have to mate to different bikes' flywheels), but it would be easy for the motor's manufacturer to interchange the connections to the motor's windings to have it spin "the other way". (I only have one spare old oilhead starter in the garage right now, so I can't directly compare them.) In Matt P's talk with Matt Normann, he does say that the part that interfaces with the flywheel is very different.

As long as there is a period of engine rotation when both valves are closed, yes there is compression. I don't know if it would be the same as normal, since the cam timing has changed.

It is not in the nose gearing. It is in the motor windings and connections which dictate which way it spins. Related, but an aside, when I am attempting to rejuvenate a stuck fuel pump I do so by repeatedly reversing the polarity of the fuel pump connections.
 
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