Chuck

That's the long and short of it.

True.. but apparently *some* springs don't break. This is probably one of them. I've also tested many variations with my gram scale in the neutral position. *Nothing* is as powerful as the Guzzi spring, but I doubt this much torsion is necessary. After all, the spring only has to hold the pawl against the pin at the start of the upshift. The eccentric will take it from there. I should take that back. The .071 spring with 25 degrees preload is about the same.. 1600 grams. Comma But 25+39 degrees is getting back to the "beyond safe travel" of that spring. Make sense? Even the weakest .071 spring still has positive pressure on the up shift, compared to a stock spring that is sacked. My gut feeling is that the .071 spring with 10 degrees preload is the one we want. It's what I'd put in my bike at this point. Third from the top in this picture. 2017-11-25_05-45-36 by Charles Stottlemyer, on Flickr Testing will continue, just the same. I'm afraid of the .080 spring stock with another active coil. Theoretically, it should be the best, but with tolerance stack up, it *might* not fit all bikes. .080" X3 equals .240". Scud's shifter gizmo measures .240". It works, somehow. If someone else's measures .230" it probably wouldn't. Do I see any eyes glazing over yet? Sorry. I've dealt with manufacturing tolerances all my life, and I'm ruling out the .080 wire with extra coil.

Gave up this afternoon at 289386. It wasn't going to break. 2017-11-27_03-50-39 by Charles Stottlemyer, on Flickr Cleaning things up reveals the reason. 2017-11-27_05-06-32 by Charles Stottlemyer, on Flickr The cam had eaten it's way into the lever. That combined with the spring doing the same thing, it's not been twisted the entire 39 degrees. More like 34. The best laid plans and all that. I need to insert some 4130 into the lever, and try again. This spring is still in great shape, though.

I noticed in some of the shadows there was a girl following you closely. How'd she like the Duck?

Uh oh. Be careful, it's a slippery slope. I started cheating on a silver Ducati with a grey Centauro, and haven't had a duck since.

207360 and counting at 6 o'clock this morning. Still showing no obvious sign of fatigue. (!) We need an energizer bunny emoticon. In related news, after filling the little gearbox with rear drive lube, it's quieter and the motor and box are running much cooler. (Guzzi content.)

Honestly, Docc.. I don't know. *Assuming* it's still going tomorrow morning, it'll have more than 200, 000. I didn't expect it to last his long.

No. (!!) Believe me, I'm surprised. I toyed with putting it in the preselector and testing how much spring pressure it had, but decided to wait until tomorrow morning if it hasn't broken. Honestly, I would never have believed it would go this long. It's eating up my steel lever, and just keeps on clacking..

Scud.. if you had installed the spring you sent me, you wouldn't have broken it. It now has over 100000 shifts, and seems to be indestructible. I'll let it go all night and see what happens.

No, it is almost completely relaxed on the upshift.

Stop the presses. I went out to check on it before going to bed, and had a squeak from the gearbox. Maybe (hopefully) just low on oil, and not a gearbox rebuild. At any rate, shut it off and will look at it today. At that point, the Guzzi spring still looked good, surprisingly enough to me. 5 hours so far.

Yes, they do. Generally, it's for the better, though. In aluminum. Not so much for spring steel. Stress relieving temp is about 350-400 F. I seriously doubt that the spring in a transmission gets that hot, though. That reminds me, It's been a little over 17000 shifts, now.. maybe I better go out an take a look.

We had company this weekend, but got out there and hit it this afternoon. Found some bearing bronze bushings, I'd already made one for the lever pivot, forgot to take a picture. Made the cam. 2017-11-25_04-52-34 by Charles Stottlemyer, on Flickr 2017-11-25_04-52-52 by Charles Stottlemyer, on Flickr Trial fit up and everything works. Even a blind hog finds an acorn now and then. 2017-11-25_04-52-09 by Charles Stottlemyer, on Flickr Made a coupler out of some ever present Delrin.. no picture again.. and hooked it up. Here are the springs to test. The Guzzi spring is in the center, .080" springs at the bottom, .071 springs at the top. Various amounts of preload. 2017-11-25_05-45-36 by Charles Stottlemyer, on Flickr Merrily clacking away, shifting 8600 times per hour. 2017-11-25_04-51-30 by Charles Stottlemyer, on Flickr Liberally squirted a mix of STP and 15-15 syn on moving stuff. I hope this isn't just a test of my low speed motor or gearbox. It was getting pretty warm after a half hour, so put a box fan on high pointed at the whole works, and now just have to be patient. Any takers on how long the Guzzi spring will go?

I get it. I'm not interested in a one day "National" in a bar in a big city.

What else needs to be said? Works for me, too. b

I doubt it will need stress relief. Most springs aren't. We'll find out after a few 10s of thousands shifts., *assuming* the gearbox of my little low speed motor holds up.

Austin is finishing up his little production job, so I'll have access to the mill over the holidays. I did learn a little more this morning. A lot of spring pressure is not a good thing. It tends to over shift, and neutral is hard to find. Too little spring pressure is not a good thing, either. It makes shifting up a function of the adjustment of the eccentric. The sacked spring I took out of the Mighty Scura has *no* pressure at the end of the up shift. Just for grins, I made an .080" spring with 2 1/2 active coils. I didn't think it would work, but it at least fits *this* particular shifter gizmo (technical term) and shifts beautifully, too. Should have plenty of travel, but I haven't run that through the spring calculator yet. I'll be back. Edit: Oh, yeah. Maximum safe travel is 56 degrees. (!) I'll look into it a little farther. 2017-11-22_11-33-07 by Charles Stottlemyer, on Flickr

It's not complicated to my eyes, and we need to test several spring versions.

I'm planning on using the bending fixture with a 15mm post and the cam driven by my low speed motor somehow. "Some sort of lever" also TBD in the picture of the cad drawing will pivot on the pin. The drawing shows the spring relaxed and at 39 degrees torsion. No Guzzi parts (except the spring) will be harmed in this exercise..

Same as one weekend in the Santa Monica Mountains, right? Seriously, that's a whole lot of shifting. Hopefully the rest of the pre-selector is up for the abuse - but I don't mind if you kill it. I'll just have a spare tranny with a dead pre-selector. All in the name of science. Oh, don't worry. I'll just be simulating what the preselector does. About the only wear yours is getting is taking it apart, trying a different spring, etc. I'm getting really good at that.

I've really not been slackin on this job.. busy. Experimented with a different way of holding the wire. Used the other end of the bending tool lever. Made several springs using this guide in the tool post. It's faster, but maybe not as repeatable. 2017-11-21_06-24-16 by Charles Stottlemyer, on Flickr Supervised Austin making steel mill oiler nozzles.. 2017-11-21_06-24-35 by Charles Stottlemyer, on Flickr I think he's a keeper, btw.. Rewired the motor.. I'ma believer in using what you brung.. I'll be able to use it as a hanger door thingy after this project. 2017-11-21_06-27-20 by Charles Stottlemyer, on Flickr Did *some* testing on various springs with my new scientific fish scale.. 2017-11-21_06-37-03 by Charles Stottlemyer, on Flickr Started on the design for the cam on the spring abuser ™. 2017-11-21_06-28-33 by Charles Stottlemyer, on Flickr Let's see now, 46 rpm X 3 = 138 X 60=8280 shifts per hour. That's 198720 shifts per 24 hours. I'll also make a couple of .080 springs with 2 1/2 active coils. My guess is they'll bind up, though. Still have to make all this stuff and get it working reliably, of course.. but i think we're on the right track. Shouldn't be much longer.

Yeah, the Grease O is basically a modernized Centauro IHMO.

Yeah. Give me a machine that is alive. I actually have to *know* how to make it work. It seems to appreciate it, and I have fun doing it. What's not to like about that? The Kid's very early 1100 Spot is very much that way. Of course, he gets it. His shiny modern Grease O sits.

Nope.

Thanks for that!