Extra neutrals between 4th and 5th when downshifting

jko_78

jko_78

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Location
The ever windy Northwest of Europe
Great, more newbie questions from that guy.... :D Yes, I have used the search function but my specific issue is either well hidden or my search fu is off a bit...

On my recent trip I noticed for the first time when you downshift from 5 to 4 and 4 to 3 you get an extra neutral. It seems to go past your intented gear, as in, when you're in 5, shift down to 4, you get a neutral, then shift up to get to 4 which seems odd. Same from 4 to 3. Whether it's always been like that or not I don't know.
Upshifts are positive in all gears, neutral and 1/2/3 also good and positive when downshifting at any revv. Warm or cold engine does not really seem to make a difference.

On some experimenting I noticed this does not happen when you downshift at higher revvs (~3000-4000) but when you let it roll with throttle closed and then shift down at low revs (<2000) e.g. when a distant traffic light is red, this happens almost all the time. I've always ridden it in the former way, so whether it's truly a new phenomenon or something that's been so for ages but never triggered I don't know.

It's a very high milage bike (~180.000km) and when you get used to it it doesn't really bother me when riding, but I do wonder if this is something to worry about. Having read the horrors of gear select adjustment & having no experience with that I'd rather not fiddle with something without knowing what it could be & if it's worrying or not.
Edit: for what it's worth, oil is ~1000km old, Motul 20W50 mineral.
 
Firstly, check that the gear lever snaps back to its original position when pushed down with your finger, as you flick your finger off the lever.
The hairpin spring, when tired, causes poor selection problems, prior to fracturing.
Always worth carrying a spare.

Gear lever return spring.jpg

Although this is from the Triple Handbook, it's the same procedure for the SF750. Check this first.
Laverda gearchange 0013.jpgLaverda gearchange 004.jpg

Then this, best done with fourth gear already selected.
Laverda gearchange 0012.jpgLaverda gearchange 002.jpg
 
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Sounds like something fixed easily with adjustment. If you aren't confident in undertaking this, maybe someone who lives nearby could help out. It bamboozles a lot of peopler but it is actually very simple.
 
In my experience, any misadjustment causes loss of either 1st or 5th gear. There are 2 springs that I am familiar with, the big spring that controls the up and down motion, that's the one I have broken and replaced 2 or 3 times and the small thin spring that controls the lateral movement of the C thing. Having that stick would be more likely to produce false neutrals between gears. And there is another spring deep in the case that requires the case to be split to replace it if it breaks. Better hope it's not that one.
 
First likely culprit would be that spring as Hamish mentions. If it weakens, gear shifting can become imprecise.
Check everything. A previously well working selection can dysfonction because of wear over time, so check the eccentric, but start with a fresh spring.
Paul
 
Although your description seems to suggest that it changes down further than intended so then an upward movement is needed to get the one gear down, when you have the bike on its center stand and can move the lever up and down while rocking the back wheel as you change gears, make sure you're getting full downwards travel of the lever. If all is well then the amount of movement upwards from the central rest point should be the same as the downward range.
I had a similar symptom where I could upshift consistently but downshifts were a problem when the return spring end was getting trapped between the moving frame and the eccentric post of the internal mechanism so that it would not permit full downwards movement of the lever.
If that's happening, then replacement of the spring ensuring it's not flipped back to front and perhaps some thin shim washers to prevent it getting misaligned and catching in the jaw should fix it.
Note that The Sock's picture above is of the triple mechanism, the twin's is similar in function and adjustment but looks quite different inside with the longer hook mechanism reaching to the far side of the pin ratchet drum. After many years and kilometers the hooks on the ratchet mechanism do wear. If you're inside the shift mechanism case, look carefully at the pins and hooks and consider replacement.
I seem to recall there was discussion here (perhaps piranha-bro2?) of making a groove in the eccentric post to keep the spring aligned to avoid this entrapment?
I find that a slower and deliberate movement of the lever is more effective than a sharp jab, fewer missed shifts.
 
arancia said:
I seem to recall there was discussion here (perhaps piranha-bro2?) of making a groove in the eccentric post to keep the spring aligned to avoid this entrapment?
Click to expand...
Correct, Arancia. i had already made a rectangular 'shim' to stop the spring fouling the moving bracket but added the groove later - it's a better shape for the job than a simple round one. I could effectively remove the shim as the groove works a treat. It also eliminates the small amount of slop that some setups exhibit. I'v e seen several selector issues that were simply the spring fouling the moving bracket - definitely a design flaw.

My selector adjustment has been very odd - it would find every gear without problem but 2nd to 3rd would not work and I'd find it was still in 2nd. and require a second shift. In the end I adjusted the opposite way you'd expect and it cured it - I don't know how but it seems to have been 'overshifting' and the hook and pin for selecting 3rd wasn't engaging.

The SFQ is a bit of a mix of selector parts, so that might explain the anomaly, because I;ve never experienced an issue like it in all the Laverdas I've worked on. And to make things even odder and odder, after replacing the perfectly adjusted setup after a selector cover R&R it has started doing it again, but only very occasionally. Not annoying enough to warrant more fiddling.

I'll post pics again, including my idea for a tool to record how far you are adjusting and in which direction. The angle alu is used in place of a screwdriver and you can mark the gasket surface of the selctor case before making an adjustment.

Selector spring retainer.jpgSelector eccentric customise.jpgSelector adjustiong tools.jpg
 
I like that cranked spanner. I am mid oil change, so again it's selector adjustment time. My 3c needs 2 goes to get into 1st, stopping at traffic lights. It needs a slight up move and then down with my foot. So slightly up with the econsentic is needed, but I suspect I don't have any adjustment left. It's such a pleasure when it's easy to get all 5 gears.
 
Wow, thanks for all the replies! I'll start with the easiest checks first -what puzzles me logically is that if it is a spring issue, why does it work at higher revvs & is the issue only with 4/5 and downshifting? Do the higher rotation speeds (I assume) make the gears mesh easier as compared to nearly idling & downshifting then?
At least it seems solvable, or at least diagnosable. It's not that it's a huge issue for me, but it would be a shame if something large, complex, or expensive (or all three!) would break. I feel I can still ride it now (provided that spring doesn't break) as compared to stop immediately before it explodes. ;)
Using the angled alu piece is clever! Makes it easier to mark the original setting so you can go back to that.

Don't have my green book at hand, but am I correct in assuming that I'll either need to lean over the bike on it's opposite side, or drain the oil as that will come out when the cover is removed?
 
It becomes a big issue if you charge into a 35kph bend while braking and downshift into a false neutral. That's why very early on I converted my 1975 3c from left shift, with in my case, sloppy pivots and links, to a way less complicated right side shift. That reduced a lot of my issues, till I broke my first spring and after fitting the new one, that caused more issues. The best bit of advice I got here is that it's very easy to cause pressure on outer gear shafts with misalignment when nipping the case up. So it's best to slowly tighten the case cover while hand rotating the rear wheel and selecting gears up and down, count them as you go and if it starts to bind up, bump the case cover till it releases.
 
jko_78 said:
Wow, thanks for all the replies! I'll start with the easiest checks first -what puzzles me logically is that if it is a spring issue, why does it work at higher revvs & is the issue only with 4/5 and downshifting? Do the higher rotation speeds (I assume) make the gears mesh easier as compared to nearly idling & downshifting then?
At least it seems solvable, or at least diagnosable. It's not that it's a huge issue for me, but it would be a shame if something large, complex, or expensive (or all three!) would break. I feel I can still ride it now (provided that spring doesn't break) as compared to stop immediately before it explodes. ;)
Using the angled alu piece is clever! Makes it easier to mark the original setting so you can go back to that.

Don't have my green book at hand, but am I correct in assuming that I'll either need to lean over the bike on it's opposite side, or drain the oil as that will come out when the cover is removed?
Click to expand...
Laverda selection is often dubious at low revs.
You need to drain the oil or lean the bike to access the selector mechanism.
Paul
 
The Sock said:
Firstly, check that the gear lever snaps back to its original position when pushed down with your finger, as you flick your finger off the lever.
Click to expand...
Figured I'd check the easiest thing first -it mostly clearly springs back, both up and down, but very occasionally (1 in 15 I'd estimate) it will go back but not as "springy", as if it moves with less spring (or more friction) occasionally.
 
I put a 20mm rimber packer under the right side leg of the centrestand, with a safety rope tied off on something solid in case you bump the bike. You might lose 100ml of oil, so try to catch it. That also gets the rear wheel off the ground so you can spin it when checking for gears. Watch where all the washers on the shafts are. And read Mr Socks' manual thread, there is a notch on a shaft that must be horizontal when the bike is in neutral, so the gearing is timed correctly. Expect to do this more than once. It can be tricky.
 
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