Lighter chain and sprockets for 750 SF ?

TeddyG

TeddyG

Hero member
Location
Portland Oregon
My existing chain is @ 3/4” wide and sprockets are @1/4” wide, so I’m assuming it’s 630 (only Regina is stamped on the plates.) So what chain will fit 520 or 530, and what other brands of sprockets will fit?
I can order the chain locally.
Thanks
 
Standard fitment for the 750s are 530. If your counter shaft sprocket has 19 teeth it's a 530.
only the 1200s came fitted with a 630. Not sure if all 1200s used 630 but the TS was.
If you want to go with a 520 you'll need to source sprockets. Not sure who supplies 520 sprockets.
My Motodd runs 520. I use an alloy rear sprocket that I turned down in a lathe and the counter shaft sprocket I ground down using a lathe and angle grinder set up on the tool post. You can anneal the front sprocket, turn it down then re harden it but I prefer grinding them.
 
Rob already asnwered your question ... I'll post anyway - had already typed it out!

Can't tell from your figures what you've got, Ted. I'm assuming you have a 530 (5/8x3/8). I've never seen a 630 on a twin. Even owners of later triples that had 630 chains have dumped them - total overkill in this day and age of high quality lightweight chains.

I'm running a 520 DID VX3 on my twin (which has a whole lot more power and torque than a stock twin). You can buy gearbox sprockets in 520 ready to fit (not sure who the suppliers are). I had a 530 in my parts bin and I sliced a sliver off it to get a 520 width using an angle grinder and cutoff wheel mounted in the cross slide of my lathe. Rear sprockets should also be available in 520. If you couldn't be bothered with sourcing 520, just fit a decent 530. I bought a blank in alu and drilled and machined it to fit my non-std (Triumph Legend 900) hub, but I'm sure you can source 520s and 530s to fit straight onto a stock hub.
 
I also fitted a DID 520 VX3. Good chain. It's done 12 track days, roughly 1600 km flat out and only had to adjust it a couple of times.
If still running a Regina chain more than likely it's original if 15000miles is correct.
What are you measuring Teddy?
Sprocket should be 3/8" and rivet to rivet should be 5/8" for a 530
 
Stocked up on 530 sprockets for my SF2 before they get thin on the ground.
The number of bikes being ridden and parts worn out doesn't warrant anybody making parts.
Paul
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motoddrob said:
530 sprockets available from all the usual lav part suppliers. Rears can be brought in blanks but the front is Laverda specific.
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If you want a lighter chain, why not just go straight to a 520? I'm sure I've seen 19T gearbox sprockets in 520 available from somewhere, maybe Redax? Redax can probably supply rears as well. If we ever run out of suitable sprockets you can 'cut-and-shut' a new outer onto a used inner - I did it when I ran a 3mm offset for tyre clearance, but have since found other solutions (to avoid unnecessary stress on the 5th gear output shaft).

Any it's not difficult to grind 530s down to 520 anyway.

530-520x19T machining.JPG530-520x19 done.JPG
 
It is far easier to just stick with buy and fit stuff if it is readily available, unless you are going for a major weight saving program or enjoy doing more work. Each of the engineering shops who trimmed down front sprockets for me said it was a prick of a job as the sprocket was ridiculously hard, in contrast to what Q says.
 
A while back, I was looking at an Afam rear sprocket for my Atlas; as usual, they have never heard of a Laverda Atlas. The Oz distributor has pics of hundreds of rear sprockets for all different makes and models of bikes with multiple numbers of mounting holes, so I asked if I could visit with an old sprocket and look for one that fits. They said no, being a Warehouse with all the sprockets sealed in boxes, it was not possible to ferret about. Nothing is ever easy. BTW, I want a steel rear Afam model 530 that has self-cleaning grooves to shed mud and grit. So down the line I will be seaching there hundeds of diagrams looking for the correct one again. Nothing is ever easy.
 
Tippie said:
Each of the engineering shops who trimmed down front sprockets for me said it was a prick of a job as the sprocket was ridiculously hard, in contrast to what Q says.
Click to expand...
I tried machining the 530 with a carbide bit but it was indeed 'a prick of a job'. The angle grinder routine in the pic was not difficult. But probably not something an engineering shop would do! I'm happy to waste 45 minutes so i can fit a 520 that will last 30,000km.
 
Vince said:
A while back, I was looking at an Afam rear sprocket for my Atlas; as usual, they have never heard of a Laverda Atlas. The Oz distributor has pics of hundreds of rear sprockets for all different makes and models of bikes with multiple numbers of mounting holes, so I asked if I could visit with an old sprocket and look for one that fits. They said no, being a Warehouse with all the sprockets sealed in boxes, it was not possible to ferret about. Nothing is ever easy. BTW, I want a steel rear Afam model 530 that has self-cleaning grooves to shed mud and grit. So down the line I will be seaching there hundeds of diagrams looking for the correct one again. Nothing is ever easy.
Click to expand...
Vince,

The Atlas uses generic Grimeca hubs, you need to search more common models using similar hubs (Gilera, Aprilia, Ducati?). Most italian marques bought-in their hubs. To my knowledge, Grimeca used the same bolt pattern for their sprockets for decades, chances are the sprocket from an early GT or S with Grimeca wheels will fit the bolt pattern... the cush drive rubber is the same.

The front twin/triple sprocket can easily be softened, machined and re-hardened. Makes the slimming down process a walk in the park.

piet
 
Tippie said:
It is far easier to just stick with buy and fit stuff if it is readily available, unless you are going for a major weight saving program or enjoy doing more work. Each of the engineering shops who trimmed down front sprockets for me said it was a prick of a job as the sprocket was ridiculously hard, in contrast to what Q says.
Click to expand...
OCT had 525 sprockets in stock for some time. I have a 520 even on my 1000 SFC if I remember right. The weight difference to the 630 is MASSIVE (1,2 kilos roughly).

With that, the load to the bearings are a point to consider, too. Gain is less between 530 and 525, but 530 to 520 is already giving the bearings some less stress with weight savings of roughly 500g.

Then change the rear chainwheel against an alloy one and you safe another kilo...
 
Received my second sprocket so I now have two complete sets.
Since I change sprockets every two chains, three for the present one, and that I change chains every 20 000 on my SF2, I have time before worrying about where the next set will come from.
It comes from AFAM. They're just up the road. I used to go there and just walk in when the company was young. Obviously, that's over. The price of success.

Incidentally, that sprocket weighs 371 g. In the real world, the motorcyclist who is weight conscious should simply be careful with what he eats and drinks.

Paul
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