Atlas Questions

Looking for a rear chain sprocket for my Laverda Atlas 530 x 26 teeth as the engine sprocket has been welded.the wheel sprocket is a 520 ?
 

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Bloody hell. What a mess. Why the fuck did they weld it all around? A little dab of weld would have stopped the sprocket coming off, and could have been ground off without ruining the entire output shaft.
 
Yep, seems the output shaft gets flogged out very easily on Atlas. Franky of The Atlas Forum made up a spreadsheet for available sprockets. Bless his golden heart. Hope this Computer thing works
file:///C:/Users/Vincent/Downloads/Laverda_Atlas_sprockets%20(4).pdf
 
I got a PM from an Atlas owner with similar clutch drag to mine, his has Corragated drum grooves and filing them smooth fixed his drag and inability to get neutral.If the plate tangs dont move smoothly and hang up that will do exactly what mine is doing as well. Great tip, seen that on high-mileage British bike.
 
Dellortoman said:
Bloody hell. What a mess. Why the fuck did they weld it all around? A little dab of weld would have stopped the sprocket coming off, and could have been ground off without ruining the entire output shaft.
Click to expand...
it's not a question of 'coming off' but 'spinning round'
the sprockets grind down the teeths of the Atlas shaft - until it's 'round' (you spin me right round like a sprocket baby)
seems to be a typical maladie of 80th trails, e.g. AT owners share the same fate.
My Atlas looked the same: after the shaft had been completely "drilled off" I put a 'final' new sprocket and the welder fixed it ;)
Anyway once the teeths are gone the shaft is kaputt - welding does not do more damage but gives you another batch of 20000 kms.
You might think of opening the engine to replace the shaft but you realise that there's no spare parts anymore and nobody in todays business is willing to 'repair' a worn shaft.
You end up by grinding off the welding, sticking a new sprocket and welding it again.
So it's not the dumbness of "people" but a design fault of 80th engineers.

good engineers (many teeths - less stress on a single one)
1747103993136.png

bad engineers (only 6 teeths and small shaft diametre, like Atlas):
1747104073713.png
 
frranky47 said:
it's not a question of 'coming off' but 'spinning round'
the sprockets grind down the teeths of the Atlas shaft - until it's 'round' (you spin me right round like a sprocket baby)
seems to be a typical maladie of 80th trails, e.g. AT owners share the same fate.
My Atlas looked the same: after the shaft had been completely "drilled off" I put a 'final' new sprocket and the welder fixed it ;)
Anyway once the teeths are gone the shaft is kaputt - welding does not do more damage but gives you another batch of 20000 kms.
You might think of opening the engine to replace the shaft but you realise that there's no spare parts anymore and nobody in todays business is willing to 'repair' a worn shaft.
You end up by grinding off the welding, sticking a new sprocket and welding it again.
So it's not the dumbness of "people" but a design fault of 80th engineers.

good engineers (many teeths - less stress on a single one)
View attachment 96458

bad engineers (only 6 teeths and small shaft diametre, like Atlas):
View attachment 96459
Click to expand...

Didn't Andy (the Kiwi one) recently (last year perhaps) have the drive sprocket shaft on his RGS re-splined and hardened in NZ?
 
Andy has an Atlas as well. Sorry, Franky missed that effect. I have no interest in major engine rebuilding anytime soon. Maybe hard shock loads on the engine, wheel stands best avoided. I dont have the wheel stand Jean anyway. I can pop over stuff, but those long balance point ones dont happen for me.
 
frranky47 said:
it's not a question of 'coming off' but 'spinning round'
the sprockets grind down the teeths of the Atlas shaft - until it's 'round' (you spin me right round like a sprocket baby)
seems to be a typical maladie of 80th trails, e.g. AT owners share the same fate.
My Atlas looked the same: after the shaft had been completely "drilled off" I put a 'final' new sprocket and the welder fixed it ;)
Anyway once the teeths are gone the shaft is kaputt - welding does not do more damage but gives you another batch of 20000 kms.
You might think of opening the engine to replace the shaft but you realise that there's no spare parts anymore and nobody in todays business is willing to 'repair' a worn shaft.
You end up by grinding off the welding, sticking a new sprocket and welding it again.
So it's not the dumbness of "people" but a design fault of 80th engineers.

good engineers (many teeths - less stress on a single one)
View attachment 96458

bad engineers (only 6 teeths and small shaft diametre, like Atlas):
View attachment 96459
Click to expand...
Hey Frranky I remember your name from the Atlas site. Do you know who ran the site or have access to the information on there? It would be great to get the information in the library on this site. Cheers AJ
 
Isn´t the Atlas engine basically the same as the road 500 and thus the Montjuic, which developed into the water-cooled Zane bikes? We hear about lots of problems from those engines but I cannot remember much talk about destroyed gearbox output shafts. What is the difference there?
 
Tippie said:
Isn´t the Atlas engine basically the same as the road 500 and thus the Montjuic, which developed into the water-cooled Zane bikes? We hear about lots of problems from those engines but I cannot remember much talk about destroyed gearbox output shafts. What is the difference there?
Click to expand...
right. Atlas has the 500 'shaft type' - the 500s probably suffer less from wear bc a) a little bit weaker engine b) street-driving style smoother than trail riding style (smoother)
In the Zanes Laverda switched to a 'multi-teeths' layout
f
 
AJ said:
Hey Frranky I remember your name from the Atlas site. Do you know who ran the site or have access to the information on there? It would be great to get the information in the library on this site. Cheers AJ
Click to expand...
indeed the sites needs a refresh, I'll do some straight talking to the owner ... ;)
 
chrisk said:
Didn't Andy (the Kiwi one) recently (last year perhaps) have the drive sprocket shaft on his RGS re-splined and hardened in NZ?
Click to expand...
Vince said:
Andy has an Atlas as well. Sorry, Franky missed that effect. I have no interest in major engine rebuilding anytime soon. Maybe hard shock loads on the engine, wheel stands best avoided. I dont have the wheel stand Jean anyway. I can pop over stuff, but those long balance point ones dont happen for me.
Click to expand...
some aspects:
- 'wheel stands' - for sure no factor :)
- trail riding = more constraint on the drive unit + using 'more torque' (low gears, low revs, engine bottom regime)
- once 'it starts' and the hardened surface is off, and there is some initial 'play', the sprocket starts working like a hammer
- 'modern' hardened sprockets (=> the shaft wears out, not the sprocket)
- repair: can be done - if one finds a company that is willing to repair a 'motorcycle shaft' (+ price-point)

there are hundrets of DIY repair 'proposals' in the communities:
- Loctite 660 - at least to slow down wear. It 'works' but you have to 're-glue' the sprocket every 1500 kms (street use). When riding offroad it's gone after a day
- the 'welding' method
- drilling off a 520 sprocket and welding the 'ring' onto the working sprocket to give it a larger base that uses the 'remaining intact milimeters' of the shaft teeths.
- constructions like this (Honda Transalp):

1747134539304.png
 
Franky from the Atlas Owners site sent me a PDF that listed a few bikes that ran the same sprockets as Atlas. I tried posting it a few pages back; its post 964 on this thread. Since I'm not so savvy in the mysteries of this stuff, it didn't appear. I will try pinging him to see if he still has it.
 
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As usual with Computer stuff and my limited brain I open the PDf above by clicking on it and see nothing, then I start clicking icons on the task bar and an almost invisable dark blue icon when clicked opens up the screen to Frankys data on sprokets. The fix as usual is radumly clicking everythink there including that very hard to see dark blue icon. RANT OVER.
BTW, thanks Franky for your work on this, I tried, but deciphering sprocket sizes and bolt patterns from various tiny pics online is very hard to do. Brilliant work, mate.
 
That countershart sproket mod with the sprag drive convertion, lockable cams is bloody cleaver as well. Now if only we could crack the cam chain issue mega ks could happen.
 
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