750 clutch sprocket weight reduction

I think the plastic sprockets were always made from nylon, a very different material to HDPE.
There are many different types of nylon (polyamide) available and it can be reinforced with fillers.
I heard good and bad stories way back about durability of nylon sprockets.
I guess they would give the chain an easier time than a steel or aluminium alloy sprocket and also absorb some more of the shock loadings.
 
Plastic sprockets are available just google platic sprockets.

In UK most are small ie 1/2" and less.

If you want them ask for 10B-1 in UK or asa50 in USA.

Andy
 
Hi Andy - under normal running circumstances - i would agree with you - but the chain only spins when starter button is pressed - it works fine - the lube will eventually free it up a bit - but, as new ones are a really loose fit as well - my one may actually be more efficient. I'm sure I'll get another 40 years out of it :D :D - Regards - Phil
 
Funny you should say that  - I;ve had several customers who have seen how slack the chain is - - then found a new oneis just the same. If I need one - I cut up part of a triple cam chainRegards - Phil
 
Plastic housing and Gears with Belt Drives and Main Chains - What's Next - Ceramic Pistons & Carbon Fiber Rods :o

Not for me I like my Kitchen Table Top Mill and it gets me to where I'm going.
 
Just found a shot of lightened chainwheel - it's a triple - but 750 is no different - Regards - Phil
 

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Oh no, now you've got me worried Phil.

I see you've lost the teeth of the centre. I'm going to go duplex, but have already started turning off the teeth from the inside row. I lost sleep over this, cause I figure that will add more stress to the end of the crank and clutch. Or, am I being silly. It was the same way that I'd seen some other pics ............................... don't tell me I have done the wrong thing?
 
G'day CK

I'd have thought it better to run the duplex chain on the inner two rows and discard the outside row of teeth. Having the primary drive closer to the engine/gearbox reduces load on those pissy little outrigger needle rollers in the primary case. You can still perforate the clutch drum to your heart's content.

The clutch sprocket is reversible, so it doesn't matter which side you machine off it. If you decide you want to run the inner two rows, just flip it over. Crank sprocket isn't reversible though. If you've taken a row of teeth off that one then you're committed to whatever chain alignment is remaining.

Cheers,
Cam
 
Well, I'm reasonably (say 95%) sure that the internal web, with the holes where the cush drive rubbers go, is on the central plane of the sprocket. So it's axially symmetrical and looks the same from either side. In theory, you should be able to take it off, flip it over so the inner row of teeth becomes the outer row, and the triplex chain will still line up with the crank sprocket.

As for the 5% uncertainty. I have spare primary drive assembly in the shed. I'll check it when I get home tonight.

Cam
 
Chris if you were running a single chain your fears would be right.

The Merc duplex is such a solid bit of kit it should be OK. Yes it will add a little more load
but I would have thought not enough to cause damage.

Andy

PS I have been slated before for saying this but as race engines are pulled down
regularly I would be running a big pin single with loads of weight saving. But there
again I dont race a Laverda :D :D :D :D :D :D
 
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