Countershaft sprocket cover variations

78jotadave

78jotadave

Hero member
Location
Palm Desert, California. (near Palm Springs)
I have been trying to assist a new Laverda owner with setting up and adjusting the gear selector mechanism up-down movement on the spindle inside the outer cover, with little to no success, and yes, the marks are lined up.
The bike does shift easily and smoothly up and down when using a tool to turn the selector drum shaft. I have performed this adjustment numerous times over the years on different bikes I have owned, but this SF 750 has me stumped. I have found multiple threads on this forum related to the selector adjustment tips and recommendations, but to no avail. So I was wondering, do all the SF 750s use the same countershaft cover/shifter mechanism? I'm grasping here.
There is a lot of movement both up and down of the adjusting lever (the one that is affected by the concentric) that I cannot reduce. Could the concentric be the source? Does anyone have a photo of it they can share? My frustration has me grasping for answers, a different cover maybe, it does have the SF 'open'selector lever.

Thanks for any input, Dave.
 
Dave rearsets or std lever. Q posted a week back an interesting mod I intend to do to reduce up and down excessive freeplay. Any gap where direct movement isn't happening could be taken out by reducing the diameter of the eccentric, allowing metal-on-metal contact and no gap. My 3c would need maybe a 1 or 2mm reduction, which now expands to a good 5mm plus of gear lever tip movement before it selects a gear. The other benefit produces shoulders on the eccentric that will stop the spring from moving and blocking an easy change.
 
Qs info is here, Dave, I don't think there are any differences in covers?
V

Post in thread '1972 SF750 stiff shifting cure'

This has frustrated me a lot over the years. A good while back, probably 25 years ago, I lost 5th for months after replacing the front sprocket and delving into this. It's surprising how it reduces cruising speed ability. Anyway, this forum has, every now and then, given me tips to sort this and other Laverda-specific oddities. One odd one was early on when up changing, I would feel the lever get blocked and staying in gear, reducing foot pressure slightly and going again would get a good change. Someone once said early bikes have corser less teeth in their dogs, apparently fixed on RGS...
 
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No real differences at all, across the entire 750 range. SFCs eventually got reinforced shifter pawl shafts, lightened primary shifter drums (the one running in the sprocket cover), chopped sprocket covers and the outer cover with integrated filler neck. Dimensionally, nothing changed throughout production.

The shifter return spring is very often fitted incorrectly with the "legs" crossing each other at an extreme angle, they should be more-or-less parallel. A washer must be placed on the shifter shaft over the spring, reducing its working space to prevent it tilting in use and blocking shaft movement. Spring "slop" to the excentric adjuster can be reduced by judicious bending of the legs or reducing the width of the seperator on the shifter pawl shaft. Removing a whisker from the ends of the pawl hooks can also cure the "doesn't-want-to-grab" syndrome once an otherwise clean run through the gears is achieved. The positioning of the sprocket cover relative to the engine case is also vital, sometimes the tolerances between the two are quite tight and can make shifting action quite stiff. On rare occasions I have found broken/distorted inner shifter drums along with worn selector forks, these are un-curable from the outside and usually block the entire shifter mechanism at some point

I have never had to resort to drastic mods to get these boxes to shift smoothly (well, as far as one could call it "smooth"), just subtle fettling of the stock parts. I do suspect similar went on along the engine assembly line in Breganze.

piet

DSCN5696.JPG
 
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What exactly are the symptoms Dave? Does it shift fine in one direction and not the other? Is it not coming out of a gear? Does it need the lever lifted a bit before it can change up again? Lots of possibles that can have different causes?
 
In my case, 3c, looking at the about picture, the thin square bit to the left of the eccentric has space off the spring. More space than I like, allowing free movement up and down. There is a considerable difference between that to what the triple is, but the principles are the same.
 
Vince,

The only difference to the triples is the drum rotation, the pawl engages on the opposite side of the drum on the triples. Spring, eccentric etc are all identical, as is the general set up between the two.

The difference in rotation goes back to footrest positioning and gear lever length. To keep movement of the shorter triple lever in an acceptable range while retaining shift effort, the internal lever ratios needed to be altered, leading to the opposing positioning of the shifter components. This means that while outwardly identical, some twin and triple parts are actually mirrored to cater for the opposite rotation. Mixing these can cause serious frustration... :ROFLMAO:

piet
 
Never had an issue with mine or anyone else's until I built the SFQ - I used parts from various sources and - I believe - the shift drum plate (inside the cases with the selector slots) came from an SF3, with an improved indent setup, as seen on later triples (pointed out to me by Piet), designed to give smoother shifting.

I could have the gearbox shifting perfectly on the centrestand but on the road it would still be in 2nd when I've clicked the lever for 3rd; a second stab and it will have gone into 3rd. I assumed it needed to be adjusted on the 'logical;' direction, but when this made it worse, I ended up adjusting it in the OPPOSITE direction from what commonsense would have deemed necessary and bingo! It worked perfectly. Stayed like that for 18 months until I removed the selector cover to seal and oil leak - refitted the cover, exact same process to eliminate slop and prevent binding, no other adjustments and ... bungo!! Problem has returned. Have tried a couple of times to get it back to 'perfect' but to no avail. It's been done again last week and is sitting there waiting for a test ride - with all my fingers and toes crossed. It's not an issue that makes the bike unrideable, but it's fukken annoying. Especially frustrating as i had managed to get it right.

So I feel your frustration Dave. But if it has shifted normally during its life, it should be possible to get it working properly with general setup and adjustment.

As mentioned on here perviously I have seen bikes lose shifting when the heavy spring fouls between the eccentric and the plate. It's why i doubled my insurance and went with not only a shim that totally eliminates the poss of the spring fouling but also grinding that shallow dip into the eccentric that both guarantees that the spring remains where it should but also eliminates the slop Vince mentions.

The mech requires two things to happen in sync: A. sufficient travel of the hooks and pins to execute a full engagement of a gear and B. the hooks and pins aligning in such a way that an up or down movement will positively engage said hooks on said pins.

If I can't get mine perfect again, I'm considering engine out and lower case off, remove selector plate and fit my old SF1 plate. Obviously not an attractive proposition c/w simple adjustment. If I could rig up an internal camera I'd LOVE to know what's going on inside when I snick from 2nd to 3rd but it is still in 2nd!
 
For the last few months, since I replaced a broken spring, my 3c has required a slight lift up before going down for 1st. When I replaced the whole inner case cover, the previous crash damage, I got Red to send me another C hook, and that's improved the change a lot. I guess 35 years does produce some wear and tear. It's least now I can do this stuff blindfolded; it used to scare me a lot before all the tips I have got here over the years. The biggest help was hearing about case cover friction and binding. Just that alone removes heaps of issues.
 
Vince said:
For the last few months, since I replaced a broken spring, my 3c has required a slight lift up before going down for 1st. When I replaced the whole inner case cover, the previous crash damage, I got Red to send me another C hook, and that's improved the change a lot. I guess 35 years does produce some wear and tear. It's least now I can do this stuff blindfolded; it used to scare me a lot before all the tips I have got here over the years. The biggest help was hearing about case cover friction and binding. Just that alone removes heaps of issues.
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It's rarely wear and tear that causes problems here, worn bits are exactly that, nicely worn in. Hardly anything can wear out here. Granted, springs and pawls can break, but wear out, not really. New bits can throw a previously perfect set up out the window and down the hill, see Quentins' woes. It's those tiny tolerances that require attention to detail that make the difference. Once working smoothly, it'll be quite OK for decades if it isn't disturbed. Ain't rocket surgery either... ;)

piet
 
Yours sounded weird, Vince. A slight upshift indicates that the hook is resting on the pin rather than 'cuddling it'. I woulda thought a miniscule adjustment in the right direction would sort that. But, hey, strange things happen in there behind them there covers!
 
Indeed, Piet. I should have just transferred my entire setup from the SF1 to the SFQ ... but then I'm introducing stuff from one set of cases to another, and to another set of gear - so potentially the same issue. Then when I go to put the original bike on the road I have to find a selector mech for it

For decades I never had to touch my selector mechanism ... didn't matter how many times it had been in various states of disassembly the motor or selector setup had been in, it never required adjustment; put it back in, check the cover for binding, reduce backlash and away I'd go.
 
Thanks to all for your replies. Over the decades, I have always achieved a nice, smooth, easy shifting on both my triples. 3 years ago, I bought a 1200 from a Forum member. It shifted quite nicely, but not as positively as my Jota. But I was able to very simply adjust the mechanism to work nicely, then a fine-tuning tap of the inner cover with a mallet, and it is perfect.
The SF750 I am trying to help a new owner with ...well, I think the spring is hanging up once the cover is replaced, some spacer or shimming could be the ticket. Qs modification could be the permanent answer to this common issue.
The bike in question is 140km away from me, so it's not like I can just drop in and fettle with it. If there are a couple of things I possess, it is patience and persistence; it will pay off, eventually. To be very fair, the owner of the bike is a very capable, competent motorcycle mechanic experiencing the idiosyncrasies of Laverda ownership. Total immersion, he bought an SF along with a Triple. Jeff, the new owner, spoke with Wolfgang, who offered him a loan of an outer cover that has a cutaway that allows viewing of the adjuster mechanism. Yeah, that's the ticket.
Updates pending
 
It's interesting that this causes problems for some and not others. I've had the selector cover off my Jota several times over the years. I just chuck it back together without any fuss and it always works. The bike has always shifted gear pretty smoothly and with minimal lever travel, despite having the left side gearshift pedal and crossover linkage.
 
Dellortoman said:
that the SFQ decided to test my reserves ofIt's interesting that this causes problems for some and not others. I've had the selector cover off my Jota several times over the years. I just chuck it back together without any fuss and it always works. The bike has always shifted gear pretty smoothly and with minimal lever travel, despite having the left side gearshift pedal and crossover linkage.
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Me too, Cam. Just that the SFQ with its 'parts bin' build decided to test my reserves!
 
My guess is Monday or Friday bikes, or it's built after a long lunch. It's the same story with heavy clutches; people say not an issue, but mine was doing me long-term physical injury. My bike had lived a hard life before I bought it. It had a racing history, nuts drilled for lockwire, Altinator cover with the bottom edge ground off and welded, etc. All the issues were fixable, or at least mine were. I also liked the challenge of setting it up to be as good as I thought it could be.
 
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