Chuck

Ok, lets get started on this problem. Austin was late this morning, so I borrowed the CNC for a few minutes to make a wire guide for the lathe. 2017-11-16_04-13-12 by Charles Stottlemyer, on Flickr This will get capped with a piece of 1/8" delrin and will fit in the lathe tool post. I'd previously made this tool that fits in the lathe chuck. The music wire and Scud's preselector magically appeared on my porch last night, too, so it's time to see what we can do. IMG_20171116_125939454 by Charles Stottlemyer, on Flickr Scud had already done a really nice job of cleaning up the preselector, and had installed a new spring. Before I took anything apart, I pulled on the pawl with a fish scale and got 2 1/2 lbs to pull it to the pin. Notice in the center of the picture how the hooked end rides on the shifter thingy. (technical term) It would probably be good to put a matching radius on that sharp corner the hook rides on. It's a little hard to see, but right in the center of the picture. IMG_20171116_132909160 by Charles Stottlemyer, on Flickr Tim had checked the total travel of the spring using (ahem) a plastic protractor, and got 38 degrees. Using my really expensive machinist's stuff, I measured 39. Nice work, Scud. Luigi apparently didn't look at his machinery handbook when he designed the spring. It has a safe travel of 30.48 degrees. (!) Previously in this thread, I had mentioned that the spring I took out of the Mighty Scura was bent 12 degrees from over travel. So. I installed the old spring, and it tests 2 lbs. on my fish scale. It's what I have.. Everyone "knows" that the spring works until it doesn't, so I'm going to experiment with a spring with 10 degrees more of an initial bend and see how it works. Time to make a proof of concept spring. IMG_20171116_160325599 by Charles Stottlemyer, on Flickr It's the one on the top. No attempt was made to make the legs the right length. I was just checking whether this tooling would work, and if the ID of the spring was correct. Right on the money. The Machinerys Handbook predicted the arbor diameter within .003". I love it when a plan comes together.. I still need to make a wire bending jig before I can make springs, so I'll have to wait until Austin is done with the mill. Probably early next week.

Yeah. You wouldn't think there would be this much oil in the breather system, but there is. When I arrived at the Wisconsin rally this summer, I saw my friend Chris from Texas with the tank off his Norge. Grabbed a beer (it *is* Wisconsin after all) and walked over to see if I could get in the way. He'd lost 2 quarts (!) and feared the worst. His breather hose was just loose on the air box.

Progress report. Today, while watching (ahem,supervising) the new pup Austin.. 2017-09-17_07-12-24 by Charles Stottlemyer, on FlickrI think he will be a keeper.. I made the first version of "spring winder tool 101 tooling." Still don't have any music wire.

Dorcia's in. Is Bev coming?

Excerpt from my journal.. I'll see if Dorcia wants to come. 5-1-14 Got suited up in my cold wx gear, rolled Rosie out, punched the start button, and nothing. (!) Took 4 or 5 punches before the starter turned. Got to Andy’s and asked if he had some contact cleaner. Pulled the start relay, sprayed it, put it back in and it didn’t miss the rest of the trip. Booger freezing cold. Many stops for Andy to warm up. He had on long johns, bibs, chaps and Carharts. (!) His trunk hinge broke in Mo. He was walking to a hardware store and dropped like a shot duck. I thought he’d had a stroke. He said his legs were so effing cold they quit working. Checked him for a concussion and stroke..seemed as ok as Andy gets. J Made Hermann, Mo, 425 miles today. They’d rolled up the streets, but we managed to find beer and food. 5-2-14 I woke up last night and decided if it was as cold as it was yesterday, I was turning around for home. Fortunately, it was tolerable and it looked like the sun would be out farther south. 19 was a pretty road south of Hermann. Fortunately, the Hub was booked up and we went to the Seville, a restored 1929 hotel. Gorgeous, and cheap. The staff was outstanding, too. $2.00 draft Mother’s little helper IPA.. J I’d take sweetie there in a heartbeat. Met Karen from Memphis who was here checking on her mother’s grave. Plays dobro in a bluegrass band, speech therapist. Bought us a round. Interesting conversation. 5-3-14 I led in the morning, and had a GREAT ride hooning around in the mountains, blowing by road blockers, etc. J It was the first time I’ve had Rosie where I could get rid of her chicken strips. 123 was a hoot. A memorable ride in perfect wx. Had late lunch at the Hub, sure glad we missed staying there. 5-4-14 Sent Karen on her way after (good) breakfast at the hotel. She said she’d be staying there every time she came back to visit her mother’s grave instead of the chain motels outside of town. I would, too. Took 62 across north Ar until we turned north and finally got on the slab. Hot hot ninetys (!) record heat, and here I was wearing my winter gear. Sweat some. J Stopped at Stan’s parent’s gravesite south of Effingham, and he put a rose on it. He said he was going to continue home, but Andy was flat too tired to go any farther. We ran up to Effingham and got a cheaper motel after Andy about had the big one when we inquired how much at a Holiday Inn express.. J Nice dinner at Fridays. Andy 010 by Charles Stottlemyer, on Flickr 021 by Charles Stottlemyer, on Flickr

I guess it *could* be uglier.. somehow.

You know Chuck what Footgoose discribes is not uncommon in many motorcycle transmissions and my view is its down to gearbox revolutions. In the scenario mentioned the box often isnt rotating at a speed high enough for proper reliable dog alignment and it gets balky and misses shifts. I can tip in a few bucks if necessary to help the cause. Ciao Sure, I've seen that on many transmissions where you are caught off guard in a higher gear and suddenly *need* to get down into first. Footgoose is an experienced rider, though.. and no doubt knows what is normal and what is not. At any rate, I have some .071 and .080" music wire ordered. It's cheap. With any luck at all, I'll have some test springs made this coming week.

He said..

Nice shoes..

You know.. I understand exactly what you are saying. After 50 some years in the trade, I have about every 'Merican drill, tap, reamer, etc. known to man. I think in 'Merican standards and convert it to that sissy metric stuff. Newton meters?? c'mon. Gimme Ft lbs and inch lbs. I still have very few metric tools. Just the same, I do metric on Guzzis just because..

Scud, I don't mean to sound like a know it all, but I think it's time for me to get more involved before we spend (cough cough) money. It's been uhh close to 50 years since I've made springs, and I *don't* have access to a spring winder, but can probably make some prototype springs on the lathe and test them to see whether we need to continue pursuing new torsion springs or continue developing the extension spring "kit." I need to spend some time in the shop breaking in a new pup on the cnc mill for the next 2 or 3 weeks, (yuck, work) so if you send me the preselector, I'll order some music wire and get right on it. (yay, play.)

FTFY

Scud.. if Footgoose thinks a 25% reduction in spring pressure is causing the quick shift issue we should hold up on making the new springs. We're over that..

The bend radius for music wire is 1 1/2 X the diameter. On the one I have, it is 1X diameter. That could be why they are breaking there.

Sounds like a plan. Don't forget the 1 1/2 dia bend radius on the short leg.

I want a spring that won't break, too. Let's go with the 895 degrees. I'll split the cost with you so if this is a bust we each only lose one fiddy. I think it's worth the gamble. Oh.. I don't suppose they'd make a couple so we could test to destruction before the order? If we *knew* they would work, we could order more than 25.

You would look good on it, Scud..

Ok using 1.52 active coils, the rate is only lowered fractionally @33.22 N-mm/degree Safe travel is 30.89 degrees. I'll be back with what smaller wire could do. Edit: Ok, I'm back. Using .071" wire with 2 1/2 active coils, which gives (in my opinion) enough clearance to not bind.. and is readily available. Rate is 20.68 N-mm/degree Safe travel 49.51 degrees. That sucker wouldn't break.. if it is strong enough to do the job. That would be 1.8 inch lbs per degree compared to 2.9 with the 2mm spring. What do you think?

Here's the spring I preemptively replaced at about 16000 miles. As you can see, it is already at 12 degrees deformation from over travel. It would have broken sooner or later. Probably sooner. I would say that even at 15 degrees, we would be operating at the limits of the spring. If we are going to go to all this trouble (fun, actually) we should come up with something that won't break in normal service. I'd like to see a good safety margin. How about stacking some feeler gauges in there to see the biggest diameter wire we can use? Then we can plug 2 1/2 coils in the calculator and see how much torque it would have with the smaller diameter wire. 2017-11-09_10-39-44 by Charles Stottlemyer, on Flickr My gut feeling is if we can't get another turn, we should at least explore the extension spring.. even though it would involve considerably more development to come up with something the home mechanic could do.

Well, now at least we know why they are breaking at both places. Normally Guzzi engineering is good (except for 4V valve trains) Maybe the same guy designed this spring, too? I take it there is no room to wind another coil on it?

Scud was right, it has 1 1/2 active coils. My bad.. That changes the Guzzi spring to a safe travel of 30.48 degrees. This is using the ASTM A228 piano wire.

Piano or music wire definitely has standards. All I've been saying is detailed in my ancient (naturally) copy of the mechanic's bible. The composition of the alloy, and how it is manufactured. There is a whole chapter on making springs. This stuff isn't rocket science. It's been known before the turn of the last century. 2017-11-08_12-50-01 by Charles Stottlemyer, on Flickr

Ah, one other thing. I was thinking that if we solved the breaking at the coil by whatever method.. why is it breaking at the bend on the short end? I wonder what minimum bend radius on music wire should be.. so looked it up. 1 1/2 stock thickness. The one I have is .078" as nearly as I can measure, so is well *under* the minimum bend radius of 3 mm. (.118") That could explain it.

^^^^^Where did you come up with that? Uhhh, there are standards for piano wire that have to be met. For instance for 304 stainless wire.. If there were no standards, making a spring would be a crap shoot.

Just for giggles, I ran the numbers with 2 active coils instead of 1 and got 48 degrees safe rotation. Don't know if there is room for that or not.